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title: "History of synthetic-aperture radar"
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source: "https://en.wikipedia.org/wiki/History_of_synthetic-aperture_radar"
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The history of synthetic-aperture radar begins in 1951, with the invention of the technology by mathematician Carl A. Wiley, and its development in the following decade. Initially developed for military use, the technology has since been applied in the field of planetary science.
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== Invention ==
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Carl A. Wiley, a mathematician at Goodyear Aircraft Company in Litchfield Park, Arizona, invented synthetic-aperture radar in June 1951 while working on a correlation guidance system for the Atlas ICBM program. In early 1952, Wiley, together with Fred Heisley and Bill Welty, constructed a concept validation system known as DOUSER ("Doppler Unbeamed Search Radar"). During the 1950s and 1960s, Goodyear Aircraft (later Goodyear Aerospace) introduced numerous advancements in SAR technology, many with help from Don Beckerleg.
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Independently of Wiley's work, experimental trials in early 1952 by Sherwin and others at the University of Illinois' Control Systems Laboratory showed results that they pointed out "could provide the basis for radar systems with greatly improved angular resolution" and might even lead to systems capable of focusing at all ranges simultaneously.
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In both of those programs, processing of the radar returns was done by electrical-circuit filtering methods. In essence, signal strength in isolated discrete bands of Doppler frequency defined image intensities that were displayed at matching angular positions within proper range locations. When only the central (zero-Doppler band) portion of the return signals was used, the effect was as if only that central part of the beam existed. That led to the term Doppler Beam Sharpening. Displaying returns from several adjacent non-zero Doppler frequency bands accomplished further "beam-subdividing" (sometimes called "unfocused radar", though it could have been considered "semi-focused"). Wiley's patent, applied for in 1954, still proposed similar processing. The bulkiness of the circuitry then available limited the extent to which those schemes might further improve resolution.
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The principle was included in a memorandum authored by Walter Hausz of General Electric that was part of the then-secret report of a 1952 Dept. of Defense summer study conference called TEOTA ("The Eyes of the Army"), which sought to identify new techniques useful for military reconnaissance and technical gathering of intelligence. A follow-on summer program in 1953 at the University of Michigan, called Project Wolverine, identified several of the TEOTA subjects, including Doppler-assisted sub-beamwidth resolution, as research efforts to be sponsored by the Department of Defense (DoD) at various academic and industrial research laboratories. In that same year, the Illinois group produced a "strip-map" image exhibiting a considerable amount of sub-beamwidth resolution.
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== Project Michigan ==
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=== Objectives ===
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A more advanced focused-radar project was among several remote sensing schemes assigned in 1953 to Project Michigan, a tri-service-sponsored (Army, Navy, Air Force) program at the University of Michigan's Willow Run Research Center (WRRC), that program being administered by the Army Signal Corps. Initially called the side-looking radar project, it was carried out by a group first known as the Radar Laboratory and later as the Radar and Optics Laboratory. It proposed to take into account, not just the short-term existence of several particular Doppler shifts, but the entire history of the steadily varying shifts from each target as the latter crossed the beam. An early analysis by Dr. Louis J. Cutrona, Weston E. Vivian, and Emmett N. Leith of that group showed that such a fully focused system should yield, at all ranges, a resolution equal to the width (or, by some criteria, the half-width) of the real antenna carried on the radar aircraft and continually pointed broadside to the aircraft's path.
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source: "https://en.wikipedia.org/wiki/History_of_synthetic-aperture_radar"
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=== Technical and scientific basis ===
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The required data processing amounted to calculating cross-correlations of the received signals with samples of the forms of signals to be expected from unit-amplitude sources at the various ranges. At that time, even large digital computers had capabilities somewhat near the levels of today's four-function handheld calculators, hence were nowhere near able to do such a huge amount of computation. Instead, the device for doing the correlation computations was to be an optical correlator.
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It was proposed that signals received by the traveling antenna and coherently detected be displayed as a single range-trace line across the diameter of the face of a cathode-ray tube, the line's successive forms being recorded as images projected onto a film traveling perpendicular to the length of that line. The information on the developed film was to be subsequently processed in the laboratory on equipment still to be devised as a principal task of the project. In the initial processor proposal, an arrangement of lenses was expected to multiply the recorded signals point-by-point with the known signal forms by passing light successively through both the signal film and another film containing the known signal pattern. The subsequent summation, or integration, step of the correlation was to be done by converging appropriate sets of multiplication products by the focusing action of one or more spherical and cylindrical lenses. The processor was to be, in effect, an optical analog computer performing large-scale scalar arithmetic calculations in many channels (with many light "rays") at once. Ultimately, two such devices would be needed, their outputs to be combined as quadrature components of the complete solution.
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A desire to keep the equipment small had led to recording the reference pattern on 35 mm film. Trials promptly showed that the patterns on the film were so fine as to show pronounced diffraction effects that prevented sharp final focusing.
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That led Leith, a physicist who was devising the correlator, to recognize that those effects in themselves could, by natural processes, perform a significant part of the needed processing, since along-track strips of the recording operated like diametrical slices of a series of circular optical zone plates. Any such plate performs somewhat like a lens, each plate having a specific focal length for any given wavelength. The recording that had been considered as scalar became recognized as pairs of opposite-sign vector ones of many spatial frequencies plus a zero-frequency "bias" quantity. The needed correlation summation changed from a pair of scalar ones to a single vector one.
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Each zone plate strip has two equal but oppositely signed focal lengths, one real, where a beam through it converges to a focus, and one virtual, where another beam appears to have diverged from, beyond the other face of the zone plate. The zero-frequency (DC bias) component has no focal point, but overlays both the converging and diverging beams. The key to obtaining, from the converging wave component, focused images that are not overlaid with unwanted haze from the other two is to block the latter, allowing only the wanted beam to pass through a properly positioned frequency-band selecting aperture.
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Each radar range yields a zone plate strip with a focal length proportional to that range. This fact became a principal complication in the design of optical processors. Consequently, technical journals of the time contain a large volume of material devoted to ways for coping with the variation of focus with range.
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For that major change in approach, the light used had to be both monochromatic and coherent, properties that were already a requirement on the radar radiation. Lasers also then being in the future, the best then-available approximation to a coherent light source was the output of a mercury vapor lamp, passed through a color filter that was matched to the lamp spectrum's green band, and then concentrated as well as possible onto a very small beam-limiting aperture. While the resulting amount of light was so weak that very long exposure times had to be used, a workable optical correlator was assembled in time to be used when appropriate data became available.
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Although creating that radar was a more straightforward task based on already-known techniques, that work did demand the achievement of signal linearity and frequency stability that were at the extreme state of the art. An adequate instrument was designed and built by the Radar Laboratory and was installed in a C-46 (Curtiss Commando) aircraft. Because the aircraft was bailed to WRRC by the U. S. Army and was flown and maintained by WRRC's own pilots and ground personnel, it was available for many flights at times matching the Radar Laboratory's needs, a feature important for allowing frequent re-testing and "debugging" of the continually developing complex equipment. By contrast, the Illinois group had used a C-46 belonging to the Air Force and flown by AF pilots only by pre-arrangement, resulting, in the eyes of those researchers, in limitation to a less-than-desirable frequency of flight tests of their equipment, hence a low bandwidth of feedback from tests. (Later work with newer Convair aircraft continued the Michigan group's local control of flight schedules.)
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source: "https://en.wikipedia.org/wiki/History_of_synthetic-aperture_radar"
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=== Results ===
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Michigan's chosen 5-foot (1.5 m)-wide World War II-surplus antenna was theoretically capable of 5-foot (1.5 m) resolution, but data from only 10% of the beamwidth was used at first, the goal at that time being to demonstrate 50-foot (15 m) resolution. It was understood that finer resolution would require the added development of means for sensing departures of the aircraft from an ideal heading and flight path, and for using that information for making needed corrections to the antenna pointing and to the received signals before processing. After numerous trials in which even small atmospheric turbulence kept the aircraft from flying straight and level enough for good 50-foot (15 m) data, one pre-dawn flight in August 1957 yielded a map-like image of the Willow Run Airport area which did demonstrate 50-foot (15 m) resolution in some parts of the image, whereas the illuminated beam width there was 900 feet (270 m). Although the program had been considered for termination by DoD due to what had seemed to be a lack of results, that first success ensured further funding to continue development leading to solutions to those recognized needs.
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== Public acknowledgement ==
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The SAR principle was first acknowledged publicly via an April 1960 press release about the U. S. Army experimental AN/UPD-1 system, which consisted of an airborne element made by Texas Instruments and installed in a Beech L-23D aircraft and a mobile ground data-processing station made by WRRC and installed in a military van. At the time, the nature of the data processor was not revealed. A technical article in the journal of the IRE (Institute of Radio Engineers) Professional Group on Military Electronics in February 1961 described the SAR principle and both the C-46 and AN/UPD-1 versions, but did not tell how the data were processed, nor that the UPD-1's maximum resolution capability was about 50 feet (15 m). However, the June 1960 issue of the IRE Professional Group on Information Theory had contained a long article on "Optical Data Processing and Filtering Systems" by members of the Michigan group. Although it did not refer to the use of those techniques for radar, readers of both journals could quite easily understand the existence of a connection between articles sharing some authors.
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== Vietnam ==
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An operational system to be carried in a reconnaissance version of the F-4 "Phantom" aircraft was quickly devised and was used briefly in Vietnam, where it failed to favorably impress its users, due to the combination of its low resolution (similar to the UPD-1's), the speckly nature of its coherent-wave images (similar to the speckliness of laser images), and the poorly understood dissimilarity of its range/cross-range images from the angle/angle optical ones familiar to military photo interpreters. The lessons it provided were well learned by subsequent researchers, operational system designers, image-interpreter trainers, and the DoD sponsors of further development and acquisition.
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== Subsequent improvement ==
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In subsequent work the technique's latent capability was eventually achieved. That work, depending on advanced radar circuit designs and precision sensing of departures from ideal straight flight, along with more sophisticated optical processors using laser light sources and specially designed very large lenses made from remarkably clear glass, allowed the Michigan group to advance system resolution, at about 5-year intervals, first to 15 feet (4.6 m), then 5 feet (1.5 m), and, by the mid-1970s, to 1 foot (the latter only over very short range intervals while processing was still being done optically). The latter levels and the associated very wide dynamic range proved suitable for identifying many objects of military concern as well as soil, water, vegetation, and ice features being studied by a variety of environmental researchers having security clearances allowing them access to what was then classified imagery. Similarly improved operational systems soon followed each of those finer-resolution steps.
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Even the 5-foot (1.5 m) resolution stage had over-taxed the ability of cathode-ray tubes (limited to about 2000 distinguishable items across the screen diameter) to deliver fine enough details to signal films while still covering wide range swaths, and taxed the optical processing systems in similar ways. However, at about the same time, digital computers finally became capable of doing the processing without similar limitation, and the consequent presentation of the images on cathode ray tube monitors instead of film allowed for better control over tonal reproduction and for more convenient image mensuration.
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Achievement of the finest resolutions at long ranges was aided by adding the capability to swing a larger airborne antenna so as to more strongly illuminate a limited target area continually while collecting data over several degrees of aspect, removing the previous limitation of resolution to the antenna width. This was referred to as the spotlight mode, which no longer produced continuous-swath images but, instead, images of isolated patches of terrain.
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== Out-of-the-atmosphere platform ==
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It was understood very early in SAR development that the extremely smooth orbital path of an out-of-the-atmosphere platform made it ideally suited to SAR operation. Early experience with artificial earth satellites had also demonstrated that the Doppler frequency shifts of signals traveling through the ionosphere and atmosphere were stable enough to permit very fine resolution to be achievable even at ranges of hundreds of kilometers. The first spaceborne SAR images of Earth were demonstrated by a project now referred to as Quill (declassified in 2012).
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== Digitisation ==
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After the initial work began, several of the capabilities for creating useful classified systems did not exist for another two decades.
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That seemingly slow rate of advances was often paced by the progress of other inventions, such as the laser, the digital computer, circuit miniaturization, and compact data storage. Once the laser appeared, optical data processing became a fast process because it provided many parallel analog channels, but devising optical chains suited to matching signal focal lengths to ranges proceeded by many stages and turned out to call for some novel optical components. Since the process depended on diffraction of light waves, it required anti-vibration mountings, clean rooms, and highly trained operators. Even at its best, its use of CRTs and film for data storage placed limits on the range depth of images.
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At several stages, attaining the frequently over-optimistic expectations for digital computation equipment proved to take far longer than anticipated. For example, the SEASAT system was ready to orbit before its digital processor became available, so a quickly assembled optical recording and processing scheme had to be used to obtain timely confirmation of system operation. In 1978, the first digital SAR processor was developed by the Canadian aerospace company MacDonald Dettwiler (MDA). When its digital processor was finally completed and used, the digital equipment of that time took many hours to create one swath of image from each run of a few seconds of data. Still, while that was a step down in speed, it was a step up in image quality. Modern methods now provide both high speed and high quality.
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== Data collection ==
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Highly accurate data can be collected by aircraft overflying the terrain in question. In the 1980s, as a prototype for instruments to be flown on the NASA Space Shuttles, NASA operated a synthetic aperture radar on a NASA Convair 990. In 1986, this plane caught fire on takeoff. In 1988, NASA rebuilt a C, L, and P-band SAR to fly on the NASA DC-8 aircraft. Called AIRSAR, it flew missions at sites around the world until 2004. Another such aircraft, the Convair 580, was flown by the Canada Center for Remote Sensing until about 1996 when it was handed over to Environment Canada due to budgetary reasons. Most land-surveying applications are now carried out by satellite observation. Satellites such as ERS-1/2, JERS-1, Envisat ASAR, and RADARSAT-1 were launched explicitly to carry out this sort of observation. Their capabilities differ, particularly in their support for interferometry, but all have collected tremendous amounts of valuable data. The Space Shuttle also carried synthetic aperture radar equipment during the SIR-A and SIR-B missions during the 1980s, the Shuttle Radar Laboratory (SRL) missions in 1994 and the Shuttle Radar Topography Mission in 2000.
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The Venera 15 and Venera 16 followed later by the Magellan space probe mapped the surface of Venus over several years using synthetic aperture radar.
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Synthetic aperture radar was first used by NASA on JPL's Seasat oceanographic satellite in 1978 (this mission also carried an altimeter and a scatterometer); it was later developed more extensively on the Spaceborne Imaging Radar (SIR) missions on the space shuttle in 1981, 1984 and 1994. The Cassini mission to Saturn used SAR to map the surface of the planet's major moon Titan, whose surface is partly hidden from direct optical inspection by atmospheric haze. The SHARAD sounding radar on the Mars Reconnaissance Orbiter and MARSIS instrument on Mars Express have observed bedrock beneath the surface of the Mars polar ice and also indicated the likelihood of substantial water ice in the Martian middle latitudes. The Lunar Reconnaissance Orbiter, launched in 2009, carries a SAR instrument called Mini-RF, which was designed largely to look for water ice deposits on the poles of the Moon.
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The Mineseeker Project is designing a system for determining whether regions contain landmines based on a blimp carrying ultra-wideband synthetic aperture radar. Initial trials show promise; the radar is able to detect even buried plastic mines.
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The National Reconnaissance Office maintains a fleet of (now declassified) synthetic aperture radar satellites commonly designated as Lacrosse or Onyx.
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In February 2009, the Sentinel R1 surveillance aircraft entered service in the RAF, equipped with the SAR-based Airborne Stand-Off Radar (ASTOR) system.
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The German Armed Forces' (Bundeswehr) military SAR-Lupe reconnaissance satellite system has been fully operational since 22 July 2008.
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As of January 2021, multiple commercial companies have started launching constellations of satellites for collecting SAR imagery of Earth.
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NASA-ISRO Synthetic Aperture Radar (NISAR) is a joint Indo-US radar project carrying an L band and an S band radar. It is the world's first radar imaging satellite to use dual frequencies.
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== Data distribution ==
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The Alaska Satellite Facility provides production, archiving and distribution to the scientific community of SAR data products and tools from active and past missions, including the June 2013 release of newly processed, 35-year-old Seasat SAR imagery.
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The Center for Southeastern Tropical Advanced Remote Sensing (CSTARS) downlinks and processes SAR data (as well as other data) from a variety of satellites and supports the University of Miami's Rosenstiel School of Marine, Atmospheric, and Earth Science. CSTARS also supports disaster relief operations, oceanographic and meteorological research, and port and maritime security research projects.
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== See also ==
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Aperture synthesis § History
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History of radar
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== References ==
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title: "Second International Congress of the History of Science"
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source: "https://en.wikipedia.org/wiki/Second_International_Congress_of_the_History_of_Science"
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The Second International Congress of the History of Science was held in London from June 29 to July 4, 1931. The Congress was organised by the International Committee of History of Science, in conjunction with the Comité International des Sciences Historiques. The History of Science Society and the Newcomen Society also supported the event. Charles Singer presided over the congress. Although organised by the International Committee of History of Science, it was during this congress that this organisation was transformed into an individual membership organisation called the International Academy of the History of Science.
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The inaugural session was held in the Great Hall of the Royal Geographical Society. This was opened by Hastings Lees-Smith, President of the Board of Education. The rest of the congress was conducted in four sessions held in the lecture hall of the Science Museum.
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== Sessions ==
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=== The Sciences as an integral Part of General Historical Study ===
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This session was chaired by Gino Loria (University of Genoa). George Clark (University of Oxford) initiated the session pleading that science has a truer sense of history than any other sphere of human activity. William Cecil Dampier then presented a hierarchical approach to the history of science. which he said should proceed from primitive emotions through law, economics, to science. This was followed by Thomas Greenwood (London University) who stressed the importance of understanding the history of mathematics in order to better grasp the history of philosophy. Archibald Hill (London University) then argued for more attention to the history of science in children's books.
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This led to a response from the Soviet delegation: Boris Zavadovsky argued that the history of science should be conceived as the history of the process of development of mankind, showing the laws to which this history conformed, as a social whole particularly in relationship to class structure. Ernst Kolman discussed a letter which Charles Darwin sent to Karl Marx which touched on the former's avoidance of the topic of religion. Modest Rubinstein added that science had progressed through economic and social of which the "great men" were merely the expression.
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=== The Teaching of the History of Science ===
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=== Historical and Contemporary Inter-relationship of the Physical and Biological Sciences ===
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=== The Interdependence of Pure and AppliedScience ===
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=== Special Session: Science at the Crossroads ===
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On the first day it was announced that there would be a "Special Session" to be held on the morning of 4 July at which the Soviet delegates would have the opportunity to present their papers. For the next five days the Soviet Embassy hosted a team of delegates, translators and proofreaders who produced the papers as separate documents by the morning of the Special Section. They were published as Science at the Crossroads 10 days later, with numerous typographical errors providing testimony to the rushed nature of their production process.
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"Theory and Practice From The Standpoint of Dialectical Materialism" by Nikolai Bukharin, Member of the Academy of Sciences, Director of the Industrial Research Department of the Supreme Economic Council, President of the Commission of the Academy of Sciences for the History of Knowledge.
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"Physics and Technology", Abram Ioffe, Member of the Academy of Sciences, Director of the Physico-Technical Institute, Leningrad.
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"Relations of Science, Technology, and Economics Under Capitalism, and in the Soviet Union" by Modest Rubinstein, Professor at the Institute of Economics, Moscow; Member of the Presidium of the Communist Academy, Moscow; Member of the Presidium of the State Planning Commission (Gosplan).
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The "Physical" and "Biological" in the Process of Organic Evolution" by Boris Zavadovsky, Director of the Institute of Neuro-Humoral Physiology, K. A. Timiriaseff, Director of the Biological Museum.
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"Dynamic and Statistical Regularity in Physics and Biology" by Ernst Kolman, President of the Association of the Scientific Institute of Natural Science, Professor of the Institute of Mathematics and Mechanics, Moscow; Member of the Presidium of the State Scientific Council.
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"The Problem of the Origin of the World's Agriculture in the Light of the Latest Investigations" by Nikolai Vavilov, Member of the Academy of Sciences, President of the Lenin Agricultural Academy.
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"The Work of Faraday and Modern Developments in the Application of Electrical Energy" by Vladimir Mitkevich, Member of the Academy of Sciences.
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"Electrification as the basis of the Technological Reconstruction in the Soviet Union" by Modest Rubinstein.
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"The Social and Economic Roots of Newton’s Principia" by Boris Hessen, Director of the Moscow Institute of Physics, Member of the Presidium of the State Scientific Council. This highly influential work became foundational in the history of science and led to modern studies of Scientific Revolutions and sociology of science.
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"The Present Crisis in the Mathematical Sciences and General Outlines for Their Reconstruction" by Ernst Kolman.
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"Short Communication on the Unpublished Writings of Karl Marx Dealing With Mathematics, The Natural Sciences and Technology and the History of these Subjects" by Ernst Kolman.
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== References ==
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== External links ==
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En español: Pablo Huerga Melcón "El Congreso de Londres de 1931"
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[Kupriyanov, V.A. (2023). The Second Congress on the History of Science and Technology in London, 1931, in the history of science of the first half of the 20th century. Part I. The origin of the idea of international congresses on the history of science. The Digital Scholar: Philosopher's Lab, 6 (4): 127–144. DOI: 10.32326/2618-9267-2023-6-4-127-144]
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[Kupriyanov, V.A. (2023). The Second Congress on the History of Science and Technology in London, 1931 in the history of science of the first half of the XXth century. Part II. The holding of the congress and its significance for historiography.The Digital Scholar: Philosopher's Lab, 6 (4): 145–167. DOI: 10.32326/2618-9267-2023-6-4-145-167]
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title: "Small science"
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source: "https://en.wikipedia.org/wiki/Small_science"
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category: "reference"
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tags: "science, encyclopedia"
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date_saved: "2026-05-05T03:12:53.295198+00:00"
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---
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Small science (in contrast to big science) is science performed in a smaller scale, such as by individuals, small teams or within community projects.
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Bodies which fund research, such as the National Science Foundation, DARPA, and the EU with its Framework programs, have a tendency to fund larger-scale research projects. Reasons include the idea that ambitious research needs significant resources devoted for its execution and the reduction of administrative and overhead costs on the funding body side. However, small science which has data that is often local and is not easily shared is funded in many areas such as chemistry and biology by these funding bodies.
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== Importance ==
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Small Science helps define the goals and directions of large scale scientific projects. In turn, results of large scale projects are often best synthesized and interpreted by the long-term efforts of the Small Science community. In addition, because Small Science is typically done at universities, it provides students and young researchers with an integral involvement in defining and solving scientific problems. Hence, small science can be seen as an important factor for bringing together science and society.
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According to the Chronicle for Higher Education, James M. Caruthers, a professor of chemical engineering at Purdue University, data from Big Science is highly organized on the front end where researchers define it before it even starts rolling off the machines, making it easier to handle, understand, and archive. Small Science is "horribly heterogeneous," and far more vast. In time, Small Science will generate two to three times more data than Big Science.
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The American Geophysical Union stresses the importance of small science in a position statement.
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== Examples of results with high impact ==
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Many historical examples show that results of Small Science can have enormous impacts:
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Galois theory, one of the foundational theories of abstract algebra was developed by Évariste Galois within just weeks.
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Albert Einstein developed his theory of special relativity as a hobby while working full-time in a patent office.
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Robert Goddard invented the liquid propelled and multi stage rockets largely on his own. These breakthroughs lead to the German V2 and the Apollo Saturn V rockets.
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== See also ==
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Citizen science
|
||||
Independent scientist
|
||||
|
||||
|
||||
== References ==
|
||||
32
data/en.wikipedia.org/wiki/Stalin_and_the_Scientists-0.md
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|
||||
---
|
||||
title: "Stalin and the Scientists"
|
||||
chunk: 1/1
|
||||
source: "https://en.wikipedia.org/wiki/Stalin_and_the_Scientists"
|
||||
category: "reference"
|
||||
tags: "science, encyclopedia"
|
||||
date_saved: "2026-05-05T03:12:54.446250+00:00"
|
||||
instance: "kb-cron"
|
||||
---
|
||||
|
||||
Stalin and the Scientists: A History of Triumph and Tragedy 1905–1953 is a 2016 popular science non-fiction book on the history of science in the Soviet Union under Joseph Stalin by English novelist and science writer, Simon Ings. It is Ings' second non-fiction book, the first being The Eye: A Natural History (2007). He had previously published eight novels.
|
||||
Stalin and the Scientists was longlisted for the 2016 Baillie Gifford Prize for Non-Fiction.
|
||||
|
||||
|
||||
== Background ==
|
||||
Ings' inspiration for Stalin and the Scientists came from Soviet psychologist, Alexander Luria's book Mind of a Mnemonist, about the life of Russian journalist and mnemonist, Solomon Shereshevsky. Ings said in 2016 interviews that Luria is often referred to as the founder of modern neuroanatomy and "the godfather of the literary genre we call popular science". "Luria's account more or less set the template for modern popular science and ... pretty much set me on the path I'm on now." Ings had considered writing a biography about Luria, but felt that while Luria's achievements were "extraordinary", considering the climate of political repression he worked in, Ings was concerned that Western readers would consider his career too ordinary, and would miss the context in which it unfolded. Ings' passion for popular science and the need to explain the context within which Luria and other Soviet scientists worked, changed what would have been a one-year "modest biography" into a "five-year behemoth" that "burned through three editors" and, Ings added, "nearly killed me".
|
||||
Ings said, as a novelist, he was "absurdly under-qualified" to tackle a book like Stalin and the Scientists, but added that only a novelist could be so "ridiculously ambitious" and "naive enough to stick his or her neck out so far". Ings felt that given the kind of science prevalent in Russia at the time, perhaps this "really has to be the job of a novelist rather than a historian". Responding to statements that this is "the first history" of Soviet science, Ings said, "Certainly no-one's been foolish enough to attempt to tell the whole story of science under Stalin in a single volume, but be assured I didn't dig this entire thing single-handed from virgin ground."
|
||||
|
||||
|
||||
== Reception ==
|
||||
In a review in The Guardian, David Holloway described Stalin and the Scientists as a "fascinating story" that reveals "the tragedy and the triumph" of Soviet science. He called it a "lively book" and complimented Ings on his "clear and simple" scientific explanations, and the way he highlighted the personalities of those involved: the "brilliant scientists", the "charlatans", the "visionaries" and the "careerists". A reviewer of the book in Publishers Weekly complimented Ings on the sensitive way in which he exposed the lives of the scientists and their experiences, and how he "ably documents the challenges, failures, and achievements of Soviet science". The reviewer commented that while Ings "can be long-winded", he "engagingly fuses history, science, and storytelling".
|
||||
British historian and author Simon Sebag Montefiore wrote in The New York Times that Ings "skillfully" portrays the lives of the scientists of this period. He called Ings "an entertaining storyteller who often captures the essence of things", and described the book as "lively and interesting" and full of "priceless nuggets and a cast of frauds, crackpots and tyrants". Montefiore added, however, that while Ings highlights the failures of Soviet science, he omits its successes, for example the Tupolev and MiG airplanes, and the T-34 tank. Montefiore was also critical of errors in the book, for example Stalin's birthday and Felix Dzerzhinsky's tenure as head of Cheka, the Soviet secret police.
|
||||
Writing in Socialist Review, John Parrington was also critical of flaws and omissions. While he described the book as "ambitious in scope", and called it "fascinating" and "important", Parrington said it is not without "elementary errors", like Ings' statement that "the Bolsheviks ... and the Mensheviks ... missed the 1905 revolution". Parrington also complained that Ings does not explain what it was that "destroyed the hopes and dreams" of Russian scientists in the 1920s when Stalin came to power.
|
||||
American science historian Loren Graham also criticised errors and omissions in the book. In a review in The Wall Street Journal, he said Ings is "a gifted writer", and called Stalin and the Scientists "a good single source" for readers new to Soviet science. But Graham felt that one of the book's shortcomings was that Ings only focuses on topics that interest him, like biology, physiology and psychology, while giving little attention to mathematics and theoretical physics. Graham also noted several "incorrect or exaggerated" statements in the book, for example: Alexei Gastev was a "leading architect of Russia's industrialisation programme"; Nikolai Bernstein "invented cybernetics"; and Stalin was "the last in a long line of European philosopher kings". Graham concluded that the book is the result of "an impressive amount of study" and "deserves attention", but "a very critical form of attention".
|
||||
|
||||
|
||||
== References ==
|
||||
|
||||
|
||||
== Cited works ==
|
||||
|
||||
Ings, Simon (2016). Stalin and the Scientists (e-book ed.). London: Faber and Faber. ISBN 978-0-571-29009-3.
|
||||
31
data/en.wikipedia.org/wiki/Supersymmetry-0.md
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|
||||
---
|
||||
title: "Supersymmetry"
|
||||
chunk: 1/6
|
||||
source: "https://en.wikipedia.org/wiki/Supersymmetry"
|
||||
category: "reference"
|
||||
tags: "science, encyclopedia"
|
||||
date_saved: "2026-05-05T03:12:55.598580+00:00"
|
||||
instance: "kb-cron"
|
||||
---
|
||||
|
||||
Supersymmetry is a theoretical framework in physics that suggests the existence of a symmetry between particles with integer spin (bosons) and particles with half-integer spin (fermions). It proposes that for every known particle, there exists a partner particle with different spin properties. There have been multiple experiments on supersymmetry that have failed to provide evidence that it exists in nature. If evidence is found, supersymmetry could help explain certain phenomena, such as the nature of dark matter and the hierarchy problem in particle physics.
|
||||
A supersymmetric theory is a theory in which the equations for force and the equations for matter are identical. In theoretical and mathematical physics, any theory with this property has the principle of supersymmetry (SUSY). Dozens of supersymmetric theories exist. In theory, supersymmetry is a type of spacetime symmetry between two basic classes of particles: bosons, which have an integer-valued spin and follow Bose–Einstein statistics, and fermions, which have a half-integer-valued spin and follow Fermi–Dirac statistics. The names of bosonic partners of fermions are prefixed with s-, because they are scalar particles. For example, if the electron existed in a supersymmetric theory, then there would be a particle called a selectron (superpartner electron), a bosonic partner of the electron.
|
||||
In supersymmetry, each particle from the class of fermions would have an associated particle in the class of bosons, and vice versa, known as a superpartner. The spin of a particle's superpartner is different by a half-integer. In the simplest supersymmetry theories, with perfectly "unbroken" supersymmetry, each pair of superpartners would share the same mass and internal quantum numbers besides spin. More complex supersymmetry theories have a spontaneously broken symmetry, allowing superpartners to differ in mass.
|
||||
Supersymmetry has various applications to different areas of physics, such as quantum mechanics, statistical mechanics, quantum field theory, condensed matter physics, nuclear physics, optics, stochastic dynamics, astrophysics, quantum gravity, and cosmology. Supersymmetry has also been applied to high-energy physics, where a supersymmetric extension of the Standard Model is a possible candidate for physics beyond the Standard Model. However, no supersymmetric extensions of the Standard Model have been experimentally verified, and some physicists are saying the theory is dead.
|
||||
|
||||
== History ==
|
||||
A supersymmetry relating mesons and baryons was first proposed, in the context of hadronic physics, by Hironari Miyazawa in 1966. This supersymmetry did not involve spacetime, that is, it concerned internal symmetry, and was broken badly. Miyazawa's work was largely ignored at the time.
|
||||
J. L. Gervais and B. Sakita (in 1971), Yu. A. Golfand and E. P. Likhtman (also in 1971), and D. V. Volkov and V. P. Akulov (1972), independently rediscovered supersymmetry in the context of quantum field theory, a radically new type of symmetry of spacetime and fundamental fields, which establishes a relationship between elementary particles of different quantum nature, bosons and fermions, and unifies spacetime and internal symmetries of microscopic phenomena. Supersymmetry with a consistent Lie-algebraic graded structure on which the Gervais−Sakita rediscovery was based directly first arose in 1971 in the context of an early version of string theory by Pierre Ramond, John H. Schwarz and André Neveu.
|
||||
In 1974, Julius Wess and Bruno Zumino identified the characteristic renormalization features of four-dimensional supersymmetric field theories, which identified them as remarkable QFTs, and they and Abdus Salam and their fellow researchers introduced early particle physics applications. The mathematical structure of supersymmetry (graded Lie superalgebras) has subsequently been applied successfully to other topics of physics, ranging from nuclear physics, critical phenomena, quantum mechanics to statistical physics, and supersymmetry remains a vital part of many proposed theories in many branches of physics.
|
||||
In particle physics, the first realistic supersymmetric version of the Standard Model was proposed in 1977 by Pierre Fayet and is known as the Minimal Supersymmetric Standard Model or MSSM for short. It was proposed to solve, amongst other things, the hierarchy problem.
|
||||
Supersymmetry was coined by Abdus Salam and John Strathdee in 1974 as a simplification of the term super-gauge symmetry used by Wess and Zumino, although Zumino also used the same term at around the same time. The term supergauge was in turn coined by Neveu and Schwarz in 1971 when they devised supersymmetry in the context of string theory.
|
||||
|
||||
== Applications ==
|
||||
|
||||
=== Extension of possible symmetry groups ===
|
||||
One reason that physicists explored supersymmetry is because it offers an extension to the more familiar symmetries of quantum field theory. These symmetries are grouped into the Poincaré group and internal symmetries and the Coleman–Mandula theorem showed that under certain assumptions, the symmetries of the S-matrix must be a direct product of the Poincaré group with a compact internal symmetry group or if there is not any mass gap, the conformal group with a compact internal symmetry group. In 1971 Golfand and Likhtman were the first to show that the Poincaré algebra can be extended through introduction of four anticommuting spinor generators (in four dimensions), which later became known as supercharges. In 1975, the Haag–Łopuszański–Sohnius theorem analyzed all possible superalgebras in the general form, including those with an extended number of the supergenerators and central charges. This extended super-Poincaré algebra paved the way for obtaining a very large and important class of supersymmetric field theories.
|
||||
|
||||
==== Supersymmetry algebra ====
|
||||
|
||||
Traditional symmetries of physics are generated by objects that transform by the tensor representations of the Poincaré group and internal symmetries. Supersymmetries, however, are generated by objects that transform by the spin representations. According to the spin-statistics theorem, bosonic fields commute while fermionic fields anticommute. Combining the two kinds of fields into a single algebra requires the introduction of a Z2-grading under which the bosons are the even elements and the fermions are the odd elements. Such an algebra is called a Lie superalgebra.
|
||||
The simplest supersymmetric extension of the Poincaré algebra is the Super-Poincaré algebra. Expressed in terms of two Weyl spinors, has the following anti-commutation relation:
|
||||
173
data/en.wikipedia.org/wiki/Supersymmetry-1.md
Normal file
173
data/en.wikipedia.org/wiki/Supersymmetry-1.md
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@ -0,0 +1,173 @@
|
||||
---
|
||||
title: "Supersymmetry"
|
||||
chunk: 2/6
|
||||
source: "https://en.wikipedia.org/wiki/Supersymmetry"
|
||||
category: "reference"
|
||||
tags: "science, encyclopedia"
|
||||
date_saved: "2026-05-05T03:12:55.598580+00:00"
|
||||
instance: "kb-cron"
|
||||
---
|
||||
|
||||
|
||||
|
||||
|
||||
{
|
||||
|
||||
Q
|
||||
|
||||
α
|
||||
|
||||
|
||||
,
|
||||
|
||||
|
||||
|
||||
|
||||
Q
|
||||
¯
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
β
|
||||
˙
|
||||
|
||||
|
||||
|
||||
|
||||
}
|
||||
=
|
||||
2
|
||||
(
|
||||
|
||||
σ
|
||||
|
||||
μ
|
||||
|
||||
|
||||
|
||||
)
|
||||
|
||||
α
|
||||
|
||||
|
||||
|
||||
β
|
||||
˙
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
P
|
||||
|
||||
μ
|
||||
|
||||
|
||||
|
||||
|
||||
{\displaystyle \{Q_{\alpha },{\bar {Q}}_{\dot {\beta }}\}=2(\sigma ^{\mu })_{\alpha {\dot {\beta }}}P_{\mu }}
|
||||
|
||||
|
||||
and all other anti-commutation relations between the
|
||||
|
||||
|
||||
|
||||
Q
|
||||
|
||||
|
||||
{\displaystyle Q}
|
||||
|
||||
s and commutation relations between the
|
||||
|
||||
|
||||
|
||||
Q
|
||||
|
||||
|
||||
{\displaystyle Q}
|
||||
|
||||
s and
|
||||
|
||||
|
||||
|
||||
P
|
||||
|
||||
|
||||
{\displaystyle P}
|
||||
|
||||
s vanish. In the above expression
|
||||
|
||||
|
||||
|
||||
|
||||
P
|
||||
|
||||
μ
|
||||
|
||||
|
||||
=
|
||||
−
|
||||
i
|
||||
|
||||
∂
|
||||
|
||||
μ
|
||||
|
||||
|
||||
|
||||
|
||||
{\displaystyle P_{\mu }=-i\partial _{\mu }}
|
||||
|
||||
are the generators of translation and
|
||||
|
||||
|
||||
|
||||
|
||||
σ
|
||||
|
||||
μ
|
||||
|
||||
|
||||
|
||||
|
||||
{\displaystyle \sigma ^{\mu }}
|
||||
|
||||
are the Pauli matrices.
|
||||
There are representations of a Lie superalgebra that are analogous to representations of a Lie algebra. Each Lie algebra has an associated Lie group and a Lie superalgebra can sometimes be extended into representations of a Lie supergroup.
|
||||
|
||||
=== Supersymmetric quantum mechanics ===
|
||||
|
||||
Supersymmetric quantum mechanics adds the SUSY superalgebra to quantum mechanics as opposed to quantum field theory. Supersymmetric quantum mechanics often becomes relevant when studying the dynamics of supersymmetric solitons, and due to the simplified nature of having fields which are only functions of time (rather than space-time), a great deal of progress has been made in this subject and it is now studied in its own right.
|
||||
SUSY quantum mechanics involves pairs of Hamiltonians which share a particular mathematical relationship, which are called partner Hamiltonians. (The potential energy terms which occur in the Hamiltonians are then known as partner potentials.) An introductory theorem shows that for every eigenstate of one Hamiltonian, its partner Hamiltonian has a corresponding eigenstate with the same energy. This fact can be exploited to deduce many properties of the eigenstate spectrum. It is analogous to the original description of SUSY, which referred to bosons and fermions. We can imagine a "bosonic Hamiltonian", whose eigenstates are the various bosons of our theory. The SUSY partner of this Hamiltonian would be "fermionic", and its eigenstates would be the theory's fermions. Each boson would have a fermionic partner of equal energy.
|
||||
|
||||
=== Supersymmetry in quantum field theory ===
|
||||
In quantum field theory, supersymmetry is motivated by solutions to several theoretical problems, for generally providing many desirable mathematical properties, and for ensuring sensible behavior at high energies. Supersymmetric quantum field theory is often much easier to analyze, as many more problems become mathematically tractable. When supersymmetry is imposed as a local symmetry, Einstein's theory of general relativity is included automatically, and the result is said to be a theory of supergravity. Another theoretically appealing property of supersymmetry is that it offers the only "loophole" to the Coleman–Mandula theorem, which prohibits spacetime and internal symmetries from being combined in any nontrivial way, for quantum field theories with very general assumptions. The Haag–Łopuszański–Sohnius theorem demonstrates that supersymmetry is the only way spacetime and internal symmetries can be combined consistently.
|
||||
While supersymmetry has not been discovered at high energy, see Section Supersymmetry in particle physics, supersymmetry was found to be effectively realized at the intermediate energy of hadronic physics where baryons and mesons are superpartners. An exception is the pion that appears as a zero mode in the mass spectrum and thus protected by the supersymmetry: It has no baryonic partner. The realization of this effective supersymmetry is readily explained in quark–diquark models: Because two different color charges close together (e.g., blue and red) appear under coarse resolution as the corresponding anti-color (e.g. anti-green), a diquark cluster viewed with coarse resolution (i.e., at the energy-momentum scale used to study hadron structure) effectively appears as an antiquark. Therefore, a baryon containing 3 valence quarks, of which two tend to cluster together as a diquark, behaves like a meson.
|
||||
|
||||
=== Supersymmetry in condensed matter physics ===
|
||||
SUSY concepts have provided useful extensions to the WKB approximation. Additionally, SUSY has been applied to disorder averaged systems both quantum and non-quantum (through statistical mechanics), the Fokker–Planck equation being an example of a non-quantum theory. The 'supersymmetry' in all these systems arises from the fact that one is modelling one particle and as such the 'statistics' do not matter. The use of the supersymmetry method provides a mathematical rigorous alternative to the replica trick, but only in non-interacting systems, which attempts to address the so-called 'problem of the denominator' under disorder averaging. For more on the applications of supersymmetry in condensed matter physics see Efetov (1997).
|
||||
In 2021, a group of researchers showed that, in theory,
|
||||
|
||||
|
||||
|
||||
N
|
||||
=
|
||||
(
|
||||
0
|
||||
,
|
||||
1
|
||||
)
|
||||
|
||||
|
||||
{\displaystyle N=(0,1)}
|
||||
|
||||
SUSY could be realised at the edge of a Moore–Read quantum Hall state. However, to date, no experiments have been done yet to realise it at an edge of a Moore–Read state. In 2022, a different group of researchers created a computer simulation of atoms in 1 dimensions that had supersymmetric topological quasiparticles.
|
||||
|
||||
=== Supersymmetry in optics ===
|
||||
In 2013, integrated optics was found to provide a fertile ground on which certain ramifications of SUSY can be explored in readily-accessible laboratory settings. Making use of the analogous mathematical structure of the quantum-mechanical Schrödinger equation and the wave equation governing the evolution of light in one-dimensional settings, one may interpret the refractive index distribution of a structure as a potential landscape in which optical wave packets propagate. In this manner, a new class of functional optical structures with possible applications in phase matching, mode conversion and space-division multiplexing becomes possible. SUSY transformations have been also proposed as a way to address inverse scattering problems in optics and as a one-dimensional transformation optics.
|
||||
|
||||
=== Supersymmetry in dynamical systems ===
|
||||
79
data/en.wikipedia.org/wiki/Supersymmetry-2.md
Normal file
79
data/en.wikipedia.org/wiki/Supersymmetry-2.md
Normal file
@ -0,0 +1,79 @@
|
||||
---
|
||||
title: "Supersymmetry"
|
||||
chunk: 3/6
|
||||
source: "https://en.wikipedia.org/wiki/Supersymmetry"
|
||||
category: "reference"
|
||||
tags: "science, encyclopedia"
|
||||
date_saved: "2026-05-05T03:12:55.598580+00:00"
|
||||
instance: "kb-cron"
|
||||
---
|
||||
|
||||
All stochastic (partial) differential equations, the models for all types of continuous time dynamical systems, possess topological supersymmetry. In the operator representation of stochastic evolution, the topological supersymmetry is the exterior derivative which is commutative with the stochastic evolution operator defined as the stochastically averaged pullback induced on differential forms by SDE-defined diffeomorphisms of the phase space. The topological sector of the so-emerging supersymmetric theory of stochastic dynamics can be recognized as the Witten-type topological field theory.
|
||||
The meaning of the topological supersymmetry in dynamical systems is the preservation of the phase space continuity—infinitely close points will remain close during continuous time evolution even in the presence of noise. When the topological supersymmetry is broken spontaneously, this property is violated in the limit of the infinitely long temporal evolution and the model can be said to exhibit (the stochastic generalization of) the butterfly effect. From a more general perspective, spontaneous breakdown of the topological supersymmetry is the theoretical essence of the ubiquitous dynamical phenomenon variously known as chaos, turbulence, self-organized criticality etc. The Goldstone theorem explains the associated emergence of the long-range dynamical behavior that manifests itself as 1/f noise, butterfly effect, and the scale-free statistics of sudden (instantonic) processes, such as earthquakes, neuroavalanches, and solar flares, known as the Zipf's law and the Richter scale.
|
||||
|
||||
==== In finance ====
|
||||
In 2021, supersymmetric quantum mechanics was applied to option pricing and the analysis of markets in finance, and to financial networks.
|
||||
|
||||
=== Supersymmetry in mathematics ===
|
||||
SUSY is also sometimes studied mathematically for its intrinsic properties. This is because it describes complex fields satisfying a property known as holomorphy, which allows holomorphic quantities to be exactly computed. This makes supersymmetric models useful "toy models" of more realistic theories. A prime example of this has been the demonstration of S-duality in four-dimensional gauge theories that interchanges particles and monopoles.
|
||||
The proof of the Atiyah–Singer index theorem is much simplified by the use of supersymmetric quantum mechanics.
|
||||
|
||||
=== Supersymmetry in string theory ===
|
||||
|
||||
Supersymmetry is an integral part of string theory, a possible theory of everything. There are two types of string theory, supersymmetric string theory or superstring theory, and non-supersymmetric string theory. By definition of superstring theory, supersymmetry is required in superstring theory at some level. However, even in non-supersymmetric string theory, a type of supersymmetry called misaligned supersymmetry is still required in the theory in order to ensure no physical tachyons appear. Any string theories without some kind of supersymmetry, such as bosonic string theory and the
|
||||
|
||||
|
||||
|
||||
|
||||
E
|
||||
|
||||
7
|
||||
|
||||
|
||||
×
|
||||
|
||||
E
|
||||
|
||||
7
|
||||
|
||||
|
||||
|
||||
|
||||
{\displaystyle E_{7}\times E_{7}}
|
||||
|
||||
,
|
||||
|
||||
|
||||
|
||||
S
|
||||
U
|
||||
(
|
||||
16
|
||||
)
|
||||
|
||||
|
||||
{\displaystyle SU(16)}
|
||||
|
||||
, and
|
||||
|
||||
|
||||
|
||||
|
||||
E
|
||||
|
||||
8
|
||||
|
||||
|
||||
|
||||
|
||||
{\displaystyle E_{8}}
|
||||
|
||||
heterotic string theories, will have a tachyon and therefore the spacetime vacuum itself would be unstable and would decay into some tachyon-free string theory usually in a lower spacetime dimension. There is no experimental evidence that either supersymmetry or misaligned supersymmetry holds in our universe, and many physicists have moved on from supersymmetry and string theory entirely due to the non-detection of supersymmetry at the LHC.
|
||||
Despite the null results for supersymmetry at the LHC so far, some particle physicists have nevertheless moved to string theory in order to resolve the naturalness crisis for certain supersymmetric extensions of the Standard Model. According to the particle physicists, there exists a concept of "stringy naturalness" in string theory, where the string theory landscape could have a power law statistical pull on soft SUSY breaking terms to large values (depending on the number of hidden sector SUSY breaking fields contributing to the soft terms). If this is coupled with an anthropic requirement that contributions to the weak scale not exceed a factor between 2 and 5 from its measured value (as argued by Agrawal et al.), then the Higgs mass is pulled up to the vicinity of 125 GeV while most sparticles are pulled to values beyond the current reach of LHC. (The Higgs was determined to have a mass of 125 GeV ±0.15 GeV in 2022.) An exception occurs for higgsinos which gain mass not from SUSY breaking but rather from whatever mechanism solves the SUSY mu problem. Light higgsino pair production in association with hard initial state jet radiation leads to a soft opposite-sign dilepton plus jet plus missing transverse energy signal.
|
||||
|
||||
== Supersymmetry in particle physics ==
|
||||
|
||||
In particle physics, a supersymmetric extension of the Standard Model is a possible candidate for undiscovered particle physics, and seen by some physicists as an elegant solution to many current problems in particle physics if confirmed correct, which could resolve various areas where current theories are believed to be incomplete and where limitations of current theories are well established. In particular, one supersymmetric extension of the Standard Model, the Minimal Supersymmetric Standard Model (MSSM), became popular in theoretical particle physics, as the Minimal Supersymmetric Standard Model is the simplest supersymmetric extension of the Standard Model that could resolve major hierarchy problems within the Standard Model, by guaranteeing that quadratic divergences of all orders will cancel out in perturbation theory. If a supersymmetric extension of the Standard Model is correct, superpartners of the existing elementary particles would be new and undiscovered particles and supersymmetry is expected to be spontaneously broken.
|
||||
There is no experimental evidence that a supersymmetric extension to the Standard Model is correct, or whether or not other extensions to current models might be more accurate. It is only since around 2010 that particle accelerators specifically designed to study physics beyond the Standard Model have become operational (i.e. the Large Hadron Collider (LHC)), and it is not known where exactly to look, nor the energies required for a successful search. However, the negative results from the LHC since 2010 have already ruled out some supersymmetric extensions to the Standard Model, and many physicists believe that the Minimal Supersymmetric Standard Model, while not ruled out, is no longer able to fully resolve the hierarchy problem.
|
||||
|
||||
=== Supersymmetric extensions of the Standard Model ===
|
||||
19
data/en.wikipedia.org/wiki/Supersymmetry-3.md
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19
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|
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||||
Incorporating supersymmetry into the Standard Model requires doubling the number of particles since there is no way that any of the particles in the Standard Model can be superpartners of each other. With the addition of new particles, there are many possible new interactions. The simplest possible supersymmetric model consistent with the Standard Model is the Minimal Supersymmetric Standard Model (MSSM) which can include the necessary additional new particles that are able to be superpartners of those in the Standard Model.
|
||||
|
||||
One of the original motivations for the Minimal Supersymmetric Standard Model came from the hierarchy problem. Due to the quadratically divergent contributions to the Higgs mass squared in the Standard Model, the quantum mechanical interactions of the Higgs boson causes a large renormalization of the Higgs mass and unless there is an accidental cancellation, the natural size of the Higgs mass is the greatest scale possible. Furthermore, the electroweak scale receives enormous Planck-scale quantum corrections. The observed hierarchy between the electroweak scale and the Planck scale must be achieved with extraordinary fine tuning. This problem is known as the hierarchy problem.
|
||||
Supersymmetry close to the electroweak scale, such as in the Minimal Supersymmetric Standard Model, would solve the hierarchy problem that afflicts the Standard Model. It would reduce the size of the quantum corrections by having automatic cancellations between fermionic and bosonic Higgs interactions, and Planck-scale quantum corrections cancel between partners and superpartners (owing to a minus sign associated with fermionic loops). The hierarchy between the electroweak scale and the Planck scale would be achieved in a natural manner, without extraordinary fine-tuning. If supersymmetry were restored at the weak scale, then the Higgs mass would be related to supersymmetry breaking which can be induced from small non-perturbative effects explaining the vastly different scales in the weak interactions and gravitational interactions.
|
||||
Another motivation for the Minimal Supersymmetric Standard Model comes from grand unification, the idea that the gauge symmetry groups should unify at high-energy. In the Standard Model, however, the weak, strong and electromagnetic gauge couplings fail to unify at high energy. In particular, the renormalization group evolution of the three gauge coupling constants of the Standard Model is somewhat sensitive to the present particle content of the theory. These coupling constants do not quite meet together at a common energy scale if we run the renormalization group using the Standard Model. After incorporating minimal SUSY at the electroweak scale, the running of the gauge couplings are modified, and joint convergence of the gauge coupling constants is projected to occur at approximately 1016 GeV. The modified running also provides a natural mechanism for radiative electroweak symmetry breaking.
|
||||
In many supersymmetric extensions of the Standard Model, such as the Minimal Supersymmetric Standard Model, there is a heavy stable particle (such as the neutralino) which could serve as a weakly interacting massive particle (WIMP) dark matter candidate. The existence of a supersymmetric dark matter candidate is related closely to R-parity. Supersymmetry at the electroweak scale (augmented with a discrete symmetry) typically provides a candidate dark matter particle at a mass scale consistent with thermal relic abundance calculations.
|
||||
The standard paradigm for incorporating supersymmetry into a realistic theory is to have the underlying dynamics of the theory be supersymmetric, but the ground state of the theory does not respect the symmetry and supersymmetry is broken spontaneously. The supersymmetry break can not be done permanently by the particles of the MSSM as they currently appear. This means that there is a new sector of the theory that is responsible for the breaking. The only constraint on this new sector is that it must break supersymmetry permanently and must give superparticles TeV scale masses. There are many models that can do this and most of their details do not matter. In order to parameterize the relevant features of supersymmetry breaking, arbitrary soft SUSY breaking terms are added to the theory which temporarily break SUSY explicitly but could never arise from a complete theory of supersymmetry breaking.
|
||||
|
||||
All of these supersymmetric partners (sparticles) are hypothetical and have not been observed experimentally. They are predicted by various supersymmetric extensions of the Standard Model.
|
||||
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||||
=== Searches and constraints for supersymmetry ===
|
||||
SUSY extensions of the Standard Model are constrained by a variety of experiments, including measurements of low-energy observables – for example, the anomalous magnetic moment of the muon at Fermilab; the WMAP dark matter density measurement and direct detection experiments – for example, XENON-100 and LUX; and by particle collider experiments, including B-physics, Higgs phenomenology and direct searches for superpartners (sparticles), at the Large Electron–Positron Collider, Tevatron and the LHC. In fact, CERN publicly states that if a supersymmetric model of the Standard Model "is correct, supersymmetric particles should appear in collisions at the LHC".
|
||||
Historically, the tightest limits were from direct production at colliders. The first mass limits for squarks and gluinos were made at CERN by the UA1 experiment and the UA2 experiment at the Super Proton Synchrotron. LEP later set very strong limits, which in 2006 were extended by the D0 experiment at the Tevatron. From 2003 to 2015, WMAP's and Planck's dark matter density measurements have strongly constrained supersymmetric extensions of the Standard Model, which, if they explain dark matter, have to be tuned to invoke a particular mechanism to sufficiently reduce the neutralino density.
|
||||
Prior to the beginning of the LHC, in 2009, fits of available data to CMSSM and NUHM1 indicated that squarks and gluinos were most likely to have masses in the 500 to 800 GeV range, though values as high as 2.5 TeV were allowed with low probabilities. Neutralinos and sleptons were expected to be quite light, with the lightest neutralino and the lightest stau most likely to be found between 100 and 150 GeV.
|
||||
The first runs of the LHC surpassed existing experimental limits from the Large Electron–Positron Collider and Tevatron and partially excluded the aforementioned expected ranges. In 2011–12, the LHC discovered a Higgs boson with a mass of about 125 GeV, and with couplings to fermions and bosons which are consistent with the Standard Model. The MSSM predicts that the mass of the lightest Higgs boson should not be much higher than the mass of the Z boson, and, in the absence of fine tuning (with the supersymmetry breaking scale on the order of 1 TeV), should not exceed 135 GeV. The LHC found no previously unknown particles other than the Higgs boson which was already suspected to exist as part of the Standard Model, and therefore no evidence for any supersymmetric extension of the Standard Model.
|
||||
Indirect methods include the search for a permanent electric dipole moment (EDM) in the known Standard Model particles, which can arise when the Standard Model particle interacts with the supersymmetric particles. The current best constraint on the electron electric dipole moment put it to be smaller than 10−28 e·cm, equivalent to a sensitivity to new physics at the TeV scale and matching that of the current best particle colliders. A permanent EDM in any fundamental particle points towards time-reversal violating physics, and therefore also CP-symmetry violation via the CPT theorem. Such EDM experiments are also much more scalable than conventional particle accelerators and offer a practical alternative to detecting physics beyond the Standard Model as accelerator experiments become increasingly costly and complicated to maintain. The current best limit for the electron's EDM has already reached a sensitivity to rule out so called 'naive' versions of supersymmetric extensions of the Standard Model.
|
||||
Research in the late 2010s and early 2020s from experimental data on the cosmological constant, LIGO noise, and pulsar timing, suggests it's very unlikely that there are any new particles with masses much higher than those which can be found in the Standard Model or the LHC. However, this research has also indicated that quantum gravity or perturbative quantum field theory will become strongly coupled before 1 PeV, leading to other new physics in the TeVs.
|
||||
|
||||
=== Current status ===
|
||||
The negative findings in the experiments disappointed many physicists, who believed that supersymmetric extensions of the Standard Model (and other theories relying upon it) were by far the most promising theories for "new" physics beyond the Standard Model, and had hoped for signs of unexpected results from the experiments. In particular, the LHC result seems problematic for the Minimal Supersymmetric Standard Model, as the value of 125 GeV is relatively large for the model and can only be achieved with large radiative loop corrections from top squarks, which many theorists consider to be "unnatural" (see naturalness and fine tuning).
|
||||
In response to the so-called "naturalness crisis" in the Minimal Supersymmetric Standard Model, some researchers have abandoned naturalness and the original motivation to solve the hierarchy problem naturally with supersymmetry, while other researchers have moved on to other supersymmetric models such as split supersymmetry. Still others have moved to string theory as a result of the naturalness crisis. Former enthusiastic supporter Mikhail Shifman went as far as urging the theoretical community to search for new ideas and accept that supersymmetry was a failed theory in particle physics. However, some researchers suggested that this "naturalness" crisis was premature because various calculations were too optimistic about the limits of masses which would allow a supersymmetric extension of the Standard Model as a solution.
|
||||
|
||||
== General supersymmetry ==
|
||||
Supersymmetry appears in many related contexts of theoretical physics. It is possible to have multiple supersymmetries and also have supersymmetric extra dimensions.
|
||||
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||||
=== Extended supersymmetry ===
|
||||
It is possible to have more than one kind of supersymmetry transformation. Theories with more than one supersymmetry transformation are known as extended supersymmetric theories. The more supersymmetry a theory has, the more constrained are the field content and interactions. Typically the number of copies of a supersymmetry is a power of 2 (1, 2, 4, 8...). In four dimensions, a spinor has four degrees of freedom and thus the minimal number of supersymmetry generators is four in four dimensions and having eight copies of supersymmetry means that there are 32 supersymmetry generators.
|
||||
The maximal number of supersymmetry generators possible is 32. Theories with more than 32 supersymmetry generators automatically have massless fields with spin greater than 2. It is not known how to make massless fields with spin greater than two interact, so the maximal number of supersymmetry generators considered is 32. This is due to the Weinberg–Witten theorem. This corresponds to an N = 8 supersymmetry theory. Theories with 32 supersymmetries automatically have a graviton.
|
||||
For four dimensions there are the following theories, with the corresponding multiplets (CPT adds a copy, whenever they are not invariant under such symmetry):
|
||||
|
||||
=== Supersymmetry in alternate numbers of dimensions ===
|
||||
It is possible to have supersymmetry in dimensions other than four. Because the properties of spinors change drastically between different dimensions, each dimension has its characteristic. In d dimensions, the size of spinors is approximately 2d/2 or 2(d−1)/2. Since the maximum number of supersymmetries is 32, the greatest number of dimensions in which a supersymmetric theory can exist is eleven.
|
||||
|
||||
=== Fractional supersymmetry ===
|
||||
Fractional supersymmetry is a generalization of the notion of supersymmetry in which the minimal positive amount of spin does not have to be 1/2 but can be an arbitrary 1/N for integer value of N. Such a generalization is possible in two or fewer spacetime dimensions.
|
||||
|
||||
== See also ==
|
||||
|
||||
== References ==
|
||||
|
||||
== Further reading ==
|
||||
|
||||
=== Theoretical introductions, free and online ===
|
||||
|
||||
=== Monographs ===
|
||||
|
||||
=== On experiments ===
|
||||
|
||||
== External links ==
|
||||
|
||||
Supersymmetry – European Organization for Nuclear Research (CERN)
|
||||
The status of supersymmetry – Symmetry Magazine (Fermilab/SLAC), January 12, 2021
|
||||
As Supersymmetry Fails Tests, Physicists Seek New Ideas – Quanta Magazine, November 20, 2012
|
||||
What is Supersymmetry? – Fermilab, May 21, 2013
|
||||
Why Supersymmetry? – Fermilab, May 31, 2013
|
||||
The Standard Model and Supersymmetry – World Science Festival, March 4, 2015
|
||||
SUSY running out of hiding places – BBC, December 11, 2012
|
||||
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|
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||||
Table-turning (also known as table-tapping, table-tipping or table-tilting) is a type of séance in which participants sit around a table, place their hands on it, and wait for rotations. The table was purportedly made to serve as a means of communicating with the spirits; the alphabet would be slowly spoken aloud and the table would tilt at the appropriate letter, thus spelling out words and sentences. The process is similar to that of a Ouija board. Scientists and skeptics consider table-turning to be the result of the ideomotor effect, or of conscious trickery.
|
||||
|
||||
|
||||
== History ==
|
||||
When the movement of spiritualism first reached Europe from America in the winter of 1852–1853, the most popular method of consulting the spirits was for several persons to sit round a table, with their hands resting on it, and wait for the table to move. If the experiment was successful, the table would rotate with considerable rapidity and would occasionally rise in the air, or perform other movements.
|
||||
Whilst most spiritualists ascribed the table movements to the agency of spirits, two investigators, count de Gasparin and professor Thury (father of René Thury) of Geneva, conducted a careful series of experiments. They claimed to have demonstrated that the movements of the table were due to a physical force emanating from the bodies of the sitters, for which they proposed the name ectenic force. Their conclusion rested on the supposed elimination of all known physical causes for the movements; but it is doubtful from the description of the experiments whether the precautions taken were sufficient to exclude unconscious muscular action (the ideomotor effect) or even deliberate fraud.
|
||||
In England, table-turning became a fashionable diversion and was practised all over the country in the year 1853. John Elliotson and his followers attributed the phenomena to mesmerism. The general public were content to find the explanation of the movements in spirits, animal magnetism, Odic force, galvanism, electricity, or even the rotation of the earth. Some Evangelical clergymen alleged that the spirits who caused the movements were of a diabolic nature. In France, Allan Kardec studied the phenomenon and concluded in The Book on Mediums that some communications were caused by an outside intelligence, as the message contained information that was not known to the group.
|
||||
|
||||
|
||||
== Scientific reception ==
|
||||
|
||||
The Scottish surgeon James Braid, the English physiologist W. B. Carpenter and others pointed out that the phenomena could depend upon the expectation of the sitters, and could be stopped altogether by appropriate suggestion.
|
||||
Michel Eugène Chevreul explained that the purported magical movement was due to involuntary and unconscious muscular reactions.
|
||||
Michael Faraday devised a simple apparatus which conclusively demonstrated that the movements he investigated were due to unconscious muscular action. The apparatus consisted of two small boards, with glass rollers between them, the whole fastened together by india-rubber bands in such a manner that the upper board could slide under lateral pressure to a limited extent over the lower one. The occurrence of such lateral movement was at once indicated by means of an upright haystalk fastened to the apparatus. When by this means it was made clear to the experimenters that it was the fingers which moved the table, the phenomena generally ceased. After this experimental approach, Faraday criticized the believers of table-turning.
|
||||
Faraday's work was followed up a century later by clinical psychologist Kenneth Batcheldor who pioneered the use of infrared video recording to observe experimental subjects in complete darkness.
|
||||
|
||||
|
||||
=== Trickery ===
|
||||
|
||||
Apart from the ideomotor effect, conscious fraudulent table tipping has also been uncovered. Professional magicians and skeptics have exposed many of the methods utilized by mediums to tip tables. The magician Chung Ling Soo described a method that involved a pin driven into the table and the use of a ring with a slot on the medium's finger. Once the pin entered the slot, the table could be lifted. Another example comes from Eusapia Palladino, who used custom-made boots with soles that extended beyond the boots' edges in order to lift tables.
|
||||
According to John Mulholland:
|
||||
|
||||
The multiplicity of methods used to tip and raise tables in a séance is almost as great as the number of mediums performing the feat. One of the simplest was to slide the hands back until one or both of the medium's thumbs could catch hold of the table top. Another way was to exert no pressure on the table at all, and in the event that the sitter opposite the medium did press on the table, to permit the table to tip far enough away from him so that he could get the toe of one foot under the table leg. He would then immediately put pressure on his side, and, holding the table between his hands and his toe, move it about at will. By this method a small table can be made to float two feet off the floor... Another method was to catch the under side of the table top with the knee; and still another was merely to kick the table into the air.
|
||||
|
||||
|
||||
== References ==
|
||||
|
||||
|
||||
== Further reading ==
|
||||
John Henry Anderson. (1855). The Fashionable Science of Parlour Magic. London. pp. 85–87
|
||||
Willis Dutcher. (1922). On the Other Side of the Footlights: An Expose of Routines, Apparatus and Deceptions Resorted to by Mediums, Clairvoyants, Fortune Tellers and Crystal Gazers in Deluding the Public. Berlin, WI: Heaney Magic. pp. 80–81
|
||||
F. Attfield Fawkes. (1920). Spiritualism Exposed. J. W. Arrowsmith Ltd. pp. 27–29
|
||||
|
||||
|
||||
== External links ==
|
||||
|
||||
"Table-turning". Psi Encyclopedia. Society for Psychical Research.
|
||||
"Modern practical guide to table tilting". ASSAP. Archived from the original on 2011-07-25. Retrieved 2006-07-19. based on the work of Kenneth Batcheldor.
|
||||
Museum of Talking Boards (official website)
|
||||
42
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||||
date_saved: "2026-05-05T03:12:59.237630+00:00"
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||||
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|
||||
---
|
||||
|
||||
A thought experiment is an imaginary scenario that is meant to elucidate or test an argument or theory. It is often an experiment that would be hard, impossible, or unethical to actually perform. It can also be an abstract hypothetical that is meant to test our intuitions about morality or other fundamental philosophical questions.
|
||||
|
||||
== History ==
|
||||
The ancient Greek δείκνυμι, deiknymi, 'thought experiment', "was the most ancient pattern of mathematical proof", and existed before Euclidean mathematics, where the emphasis was on the conceptual, rather than on the experimental part of a thought experiment.
|
||||
Johann Witt-Hansen established that Hans Christian Ørsted was the first to use the equivalent German term Gedankenexperiment c. 1812. Ørsted was also the first to use the equivalent term Gedankenversuch in 1820.
|
||||
By 1883, Ernst Mach used Gedankenexperiment in a different sense, to denote exclusively the imaginary conduct of a real experiment that would be subsequently performed as a real physical experiment by his students. Physical and mental experimentation could then be contrasted: Mach asked his students to provide him with explanations whenever the results from their subsequent, real, physical experiment differed from those of their prior, imaginary experiment.
|
||||
The English term thought experiment was coined as a calque of Gedankenexperiment, and it first appeared in the 1897 English translation of one of Mach's papers. Prior to its emergence, the activity of posing hypothetical questions that employed subjunctive reasoning had existed for a very long time for both scientists and philosophers. The irrealis moods are ways to categorize it or to speak about it. This helps explain the extremely wide and diverse range of the application of the term thought experiment once it had been introduced into English.
|
||||
|
||||
Galileo's demonstration that falling objects must fall at the same rate regardless of their masses was a significant step forward in the history of modern science. This is widely thought to have been a straightforward physical demonstration, involving climbing up the Leaning Tower of Pisa and dropping two heavy weights off it, whereas in fact, it was a logical demonstration, using the thought experiment technique. The experiment is described by Galileo in his 1638 work Two New Sciences thus:
|
||||
|
||||
Salviati: If then we take two bodies whose natural speeds are different, it is clear that on uniting the two, the more rapid one will be partly retarded by the slower, and the slower will be somewhat hastened by the swifter. Do you not agree with me in this opinion?Simplicio: You are unquestionably right.Salviati: But if this is true, and if a large stone moves with a speed of, say, eight while a smaller moves with a speed of four, then when they are united, the system will move with a speed less than eight; but the two stones when tied together make a stone larger than that which before moved with a speed of eight. Hence the heavier body moves with less speed than the lighter; an effect which is contrary to your supposition. Thus you see how, from your assumption that the heavier body moves more rapidly than the lighter one, I infer that the heavier body moves more slowly.
|
||||
|
||||
== Uses ==
|
||||
Thought experiments may be used to explore a hypothesis and the implementation of theories around it. They are also used in education, or for personal entertainment.
|
||||
Examples of thought experiments include Schrödinger's cat, that was meant to attack the Copenhagen Interpretation of quantum mechanics by showing that its assumptions could lead to the seemingly absurd condition of a cat being simultaneously alive and dead, and Maxwell's demon, which attempts to demonstrate the ability of a hypothetical finite being to violate the 2nd law of thermodynamics.
|
||||
It is a common element of science-fiction stories.
|
||||
Thought experiments, which are well-structured, well-defined hypothetical questions that employ subjunctive reasoning (irrealis moods) – "What might happen (or, what might have happened) if . . . " – have been used to pose questions in philosophy at least since Greek antiquity, some pre-dating Socrates. In physics and other sciences many thought experiments date from the 19th and especially the 20th Century, but examples can be found at least as early as Galileo.
|
||||
In thought experiments, we gain new information by rearranging or reorganizing empirical data in a new way and drawing new inferences from them, or by looking at these data from a different and unusual perspective. In Galileo's thought experiment, for example, the rearrangement of empirical experience consists of the original idea of combining bodies of different weights.
|
||||
Thought experiments have been used in philosophy (especially ethics), physics, and other fields (such as cognitive psychology, history, political science, economics, social psychology, law, organizational studies, marketing, and epidemiology). In law, the synonym "hypothetical" is frequently used for such experiments.
|
||||
Regardless of their intended goal, all thought experiments display a patterned way of thinking that is designed to allow us to explain, predict, and control events in a better and more productive way.
|
||||
|
||||
=== Theoretical consequences ===
|
||||
In terms of their theoretical consequences, thought experiments generally:
|
||||
|
||||
challenge (or even refute) a prevailing theory, often involving the device known as reductio ad absurdum, (as in Galileo's original argument, a proof by contradiction),
|
||||
confirm a prevailing theory,
|
||||
establish a new theory, or
|
||||
simultaneously refute a prevailing theory and establish a new theory through a process of mutual exclusion
|
||||
|
||||
=== Practical applications ===
|
||||
Thought experiments can produce some very important and different outlooks on previously unknown or unaccepted theories. However, they may make those theories themselves irrelevant, and could possibly create new problems that are just as difficult, or possibly more difficult to resolve.
|
||||
In terms of their practical application, thought experiments are generally created to:
|
||||
41
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||||
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|
||||
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||||
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||||
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|
||||
date_saved: "2026-05-05T03:12:59.237630+00:00"
|
||||
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|
||||
---
|
||||
|
||||
challenge the prevailing status quo (which includes activities such as correcting misinformation (or misapprehension), identify flaws in the argument(s) presented, to preserve (for the long-term) objectively established fact, and to refute specific assertions that some particular thing is permissible, forbidden, known, believed, possible, or necessary)
|
||||
extrapolate beyond (or interpolate within) the boundaries of already established fact
|
||||
predict and forecast the (otherwise) indefinite and unknowable future
|
||||
explain the past
|
||||
facilitate the retrodiction, postdiction and hindcasting of the otherwise indefinite and unknowable past
|
||||
facilitate decision making, choice, and strategy selection
|
||||
solve problems, and generate ideas;
|
||||
move current unsolved problems into another more productive problem space (e.g. functional fixedness)
|
||||
attribute causation, preventability, blame, and responsibility for specific outcomes
|
||||
assess culpability and compensatory damages in social and legal contexts
|
||||
ensure the repeat of past success
|
||||
examine the extent to which past events might have occurred differently
|
||||
ensure the future avoidance of past failures
|
||||
|
||||
== Fields ==
|
||||
Thought experiments have been used in a variety of fields, including philosophy, law, physics, and mathematics. In philosophy they have been used at least since classical antiquity, some pre-dating Socrates. In law, they were well known to Roman lawyers quoted in the Digest. In physics and other sciences, notable thought experiments date from the 19th and, especially, the 20th century; but examples can be found at least as early as Galileo.
|
||||
|
||||
=== Philosophy ===
|
||||
In philosophy, a thought experiment typically presents an imagined scenario with the intention of eliciting an intuitive or reasoned response about the way things are in the thought experiment. (Philosophers might also supplement their thought experiments with theoretical reasoning designed to support the desired intuitive response.) The scenario will typically be designed to target a particular philosophical notion, such as morality, or the nature of the mind or linguistic reference. The response to the imagined scenario is supposed to tell us about the nature of that notion in any scenario, real or imagined.
|
||||
For example, a thought experiment might present a situation in which an agent intentionally kills an innocent for the benefit of others. Here, the relevant question is not whether the action is moral or not, but more broadly whether a moral theory is correct that says morality is determined solely by an action's consequences (See Consequentialism). John Searle imagines a man in a locked room who receives written sentences in Chinese, and returns written sentences in Chinese, according to a sophisticated instruction manual. Here, the relevant question is not whether or not the man understands Chinese, but more broadly, whether a functionalist theory of mind is correct.
|
||||
It is generally hoped that there is universal agreement about the intuitions that a thought experiment elicits. (Hence, in assessing their own thought experiments, philosophers may appeal to "what we should say," or some such locution.) A successful thought experiment will be one in which intuitions about it are widely shared. But often, philosophers differ in their intuitions about the scenario.
|
||||
Other philosophical uses of imagined scenarios arguably are thought experiments also. In one use of scenarios, philosophers might imagine persons in a particular situation (maybe ourselves), and ask what they would do.
|
||||
For example, in the veil of ignorance, John Rawls asks us to imagine a group of persons in a situation where they know nothing about themselves, and are charged with devising a social or political organization. The use of the state of nature to imagine the origins of government, as by Thomas Hobbes and John Locke, may also be considered a thought experiment. Søren Kierkegaard explored the possible ethical and religious implications of Abraham's binding of Isaac in Fear and Trembling. Similarly, Friedrich Nietzsche, in On the Genealogy of Morals, speculated about the historical development of Judeo-Christian morality, with the intent of questioning its legitimacy.
|
||||
An early written thought experiment was Plato's allegory of the cave. Another historic thought experiment was Avicenna's "floating man" thought experiment in the 11th century. He asked his readers to imagine themselves suspended in the air isolated from all sensations in order to demonstrate human self-awareness and self-consciousness, and the substantiality of the soul.
|
||||
|
||||
=== Science ===
|
||||
Scientists tend to use thought experiments as imaginary, "proxy" experiments prior to a real, "physical" experiment (Ernst Mach always argued that these gedankenexperiments were "a necessary precondition for physical experiment"). In these cases, the result of the "proxy" experiment will often be so clear that there will be no need to conduct a physical experiment at all.
|
||||
Scientists also use thought experiments when particular physical experiments are impossible to conduct (Carl Gustav Hempel labeled these sorts of experiment "theoretical experiments-in-imagination"), such as Einstein's thought experiment of chasing a light beam, leading to special relativity. This is a unique use of a scientific thought experiment, in that it was never carried out, but led to a successful theory, proven by other empirical means.
|
||||
|
||||
== Properties ==
|
||||
Further categorization of thought experiments can be attributed to specific properties.
|
||||
74
data/en.wikipedia.org/wiki/Thought_experiment-2.md
Normal file
74
data/en.wikipedia.org/wiki/Thought_experiment-2.md
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@ -0,0 +1,74 @@
|
||||
---
|
||||
title: "Thought experiment"
|
||||
chunk: 3/3
|
||||
source: "https://en.wikipedia.org/wiki/Thought_experiment"
|
||||
category: "reference"
|
||||
tags: "science, encyclopedia"
|
||||
date_saved: "2026-05-05T03:12:59.237630+00:00"
|
||||
instance: "kb-cron"
|
||||
---
|
||||
|
||||
=== Possibility ===
|
||||
In many thought experiments, the scenario would be nomologically possible, or possible according to the laws of nature. John Searle's Chinese room is nomologically possible.
|
||||
Some thought experiments present scenarios that are not nomologically possible. In his Twin Earth thought experiment, Hilary Putnam asks us to imagine a scenario in which there is a substance with all of the observable properties of water (e.g., taste, color, boiling point), but is chemically different from water. It has been argued that this thought experiment is not nomologically possible, although it may be possible in some other sense, such as metaphysical possibility. It is debatable whether the nomological impossibility of a thought experiment renders intuitions about it moot.
|
||||
In some cases, the hypothetical scenario might be considered metaphysically impossible, or impossible in any sense at all. David Chalmers says that we can imagine that there are zombies, or persons who are physically identical to us in every way but who lack consciousness. This is supposed to show that physicalism is false. However, some argue that zombies are inconceivable: we can no more imagine a zombie than we can imagine that 1+1=3. Others have claimed that the conceivability of a scenario may not entail its possibility.
|
||||
|
||||
=== Causal reasoning ===
|
||||
The first characteristic pattern that thought experiments display is their orientation
|
||||
in time. They are either:
|
||||
|
||||
Antefactual speculations: experiments that speculate about what might have happened prior to a specific, designated event, or
|
||||
Postfactual speculations: experiments that speculate about what may happen subsequent to (or consequent upon) a specific, designated event.
|
||||
The second characteristic pattern is their movement in time in relation to "the present
|
||||
moment standpoint" of the individual performing the experiment; namely, in terms of:
|
||||
|
||||
Their temporal direction: are they past-oriented or future-oriented?
|
||||
Their temporal sense:
|
||||
(a) in the case of past-oriented thought experiments, are they examining the consequences of temporal "movement" from the present to the past, or from the past to the present? or,
|
||||
(b) in the case of future-oriented thought experiments, are they examining the consequences of temporal "movement" from the present to the future, or from the future to the present?
|
||||
|
||||
=== Relation to real experiments ===
|
||||
The relation to real experiments can be quite complex, as can be seen again from an example going back to Albert Einstein. In 1935, with two coworkers, he published a paper on a newly created subject called later the EPR effect (EPR paradox). In this paper, starting from certain philosophical assumptions, on the basis of a rigorous analysis of a certain, complicated, but in the meantime assertedly realizable model, he came to the conclusion that quantum mechanics should be described as "incomplete". Niels Bohr asserted a refutation of Einstein's analysis immediately, and his view prevailed. After some decades, it was asserted that feasible experiments could prove the error of the EPR paper. These experiments tested the Bell inequalities published in 1964 in a purely theoretical paper. The above-mentioned EPR philosophical starting assumptions were considered to be falsified by the empirical fact (e.g. by the optical real experiments of Alain Aspect).
|
||||
Thus thought experiments belong to a theoretical discipline, usually to theoretical physics, but often to theoretical philosophy. In any case, it must be distinguished from a real experiment, which belongs naturally to the experimental discipline and has "the final decision on true or not true", at least in physics.
|
||||
|
||||
=== Interactivity ===
|
||||
Thought experiments can also be interactive where the author invites people into his thought process through providing alternative paths with alternative outcomes within the narrative, or through interaction with a programmed machine, like a computer program.
|
||||
Thanks to the advent of the Internet, the digital space has lent itself as a new medium for a new kind of thought experiments. The philosophical work of Stefano Gualeni, for example, focuses on the use of virtual worlds to materialize thought experiments and to playfully negotiate philosophical ideas. His arguments were originally presented in his 2015 book Virtual Worlds as Philosophical Tools.
|
||||
Gualeni's argument is that the history of philosophy has, until recently, merely been the history of written thought, and digital media can complement and enrich the limited and almost exclusively linguistic approach to philosophical thought. He considers virtual worlds (like those interactively encountered in videogames) to be philosophically viable and advantageous. This is especially the case in thought experiments, when the recipients of a certain philosophical notion or perspective are expected to objectively test and evaluate different possible courses of action, or in cases where they are confronted with interrogatives concerning non-actual or non-human phenomenologies.
|
||||
|
||||
== Examples ==
|
||||
|
||||
=== Humanities ===
|
||||
|
||||
=== Physics ===
|
||||
|
||||
=== Philosophy ===
|
||||
|
||||
=== Mathematics ===
|
||||
|
||||
=== Biology ===
|
||||
Levinthal paradox
|
||||
Rotating locomotion in living systems
|
||||
|
||||
=== Computer science ===
|
||||
|
||||
=== Economics ===
|
||||
Broken window fallacy (law of unintended consequences, opportunity cost)
|
||||
Laffer Curve
|
||||
|
||||
== See also ==
|
||||
|
||||
== Notes ==
|
||||
|
||||
== References ==
|
||||
|
||||
== Further reading ==
|
||||
|
||||
== Bibliography ==
|
||||
|
||||
== External links ==
|
||||
|
||||
Thought experiment at PhilPapers
|
||||
Thought experiment at the Indiana Philosophy Ontology Project
|
||||
Stevinus, Galileo, and Thought Experiments Short essay by S. Abbas Raza of 3 Quarks Daily
|
||||
Thought experiment generator, a visual aid to running your own thought experiment
|
||||
33
data/en.wikipedia.org/wiki/Traditional_knowledge-0.md
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33
data/en.wikipedia.org/wiki/Traditional_knowledge-0.md
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@ -0,0 +1,33 @@
|
||||
---
|
||||
title: "Traditional knowledge"
|
||||
chunk: 1/4
|
||||
source: "https://en.wikipedia.org/wiki/Traditional_knowledge"
|
||||
category: "reference"
|
||||
tags: "science, encyclopedia"
|
||||
date_saved: "2026-05-05T03:13:00.402589+00:00"
|
||||
instance: "kb-cron"
|
||||
---
|
||||
|
||||
Traditional knowledge (TK), indigenous knowledge (IK), folk knowledge, and local knowledge generally refers to knowledge systems embedded in the cultural traditions of regional, indigenous, or local communities.
|
||||
Traditional knowledge includes types of knowledge about traditional technologies of areas such as subsistence (e.g. tools and techniques for hunting or agriculture), midwifery, ethnobotany and ecological knowledge, traditional medicine, celestial navigation, craft skills, ethnoastronomy, climate, and others. These systems of knowledge are generally based on accumulations of empirical observation of and interaction with the environment, transmitted orally across generations.
|
||||
The World Intellectual Property Organization (WIPO) and the United Nations (UN) include traditional cultural expressions (TCE) in their respective definitions of indigenous knowledge. Traditional knowledge systems and cultural expressions exist in the forms of culture, stories, legends, folklore, rituals, songs, and laws, languages, songlines, dance, games, mythology, designs, visual art and architecture.
|
||||
|
||||
== Characteristics and related concepts ==
|
||||
|
||||
A report of the International Council for Science (ICSU) Study Group on Science and Traditional Knowledge characterises traditional knowledge as:
|
||||
|
||||
a cumulative body of knowledge, know-how, practices and representations maintained and developed by peoples with extended histories of interaction with the natural environment. These sophisticated sets of understandings, interpretations and meanings are part and parcel of a cultural complex that encompasses language, naming and classification systems, resource use practices, ritual, spirituality and worldview.
|
||||
|
||||
Traditional knowledge typically distinguishes one community from another. In some communities, traditional knowledge takes on personal and spiritual meanings. Traditional knowledge can also reflect a community's interests. Some communities depend on their traditional knowledge for survival. Traditional knowledge regarding the environment, such as taboos, proverbs and cosmological knowledge systems, may provide a conservation ethos for biodiversity preservation. This is particularly true of traditional environmental knowledge, which refers to a "particular form of place-based knowledge of the diversity and interactions among plant and animal species, landforms, watercourses, and other qualities of the biophysical environment in a given place". As an example of a society with a wealth of traditional ecological knowledge (TEK), the South American Kayapo people, have developed an extensive classification system of ecological zones of the Amazonian tropical savannah (i.e., campo / cerrado) to better manage the land.
|
||||
Some social scientists conceptualise knowledge within a naturalistic framework and emphasize the gradation of recent knowledge into knowledge acquired over many generations. These accounts use terms like adaptively acquired knowledge, socially constructed knowledge, and other terms that emphasize the social aspects of knowledge. Local knowledge and traditional knowledge may be thought of as distinguished by the length of time they have existed, from decades to centuries or millennia.
|
||||
On the other hand, indigenous and local communities themselves may perceive traditional knowledge very differently. The knowledge of indigenous and local communities is often embedded in a cosmology, and any distinction between "intangible" knowledge and physical things can become blurred. Indigenous peoples often say that indigenous knowledge is holistic, and cannot be meaningfully separated from the lands and resources available to them. Chamberlin (2003) writes of a Gitksan elder from British Columbia confronted by a government land-claim: "If this is your land," he asked, "where are your stories?"
|
||||
Indigenous and local communities often do not have strong traditions of ownership over knowledge that resemble the modern forms of private ownership. Many have clear traditions of custodianship over knowledge, and customary law may guide who may use different kinds of knowledge at particular times and places, and specify obligations that accompany the use of knowledge. For example, a hunter might be permitted to kill an animal only to feed the community, and not to feed himself. From an indigenous perspective, misappropriation and misuse of knowledge may be offensive to traditions, and may have spiritual and physical repercussions in indigenous cosmological systems. Consequently, indigenous and local communities argue that others' use of their traditional knowledge warrants respect and sensitivity. Critics of traditional knowledge, however, see such demands for "respect" as an attempt to prevent unsubstantiated beliefs from being subjected to the same scrutiny as other knowledge-claims. This has particular significance for environmental management because the spiritual component of "traditional knowledge" can justify any activity, including the unsustainable harvesting of resources.
|
||||
|
||||
=== Terminology ===
|
||||
|
||||
Traditional Knowledge (TK) and Traditional Cultural Expressions (TCE) are both types of Indigenous Knowledge (IK), according to the definitions and terminology used in the UN Declaration on the Rights of Indigenous Peoples (UNDRIP) and by the World Intellectual Property Organization (WIPO). While often used synonymously, the term "traditional knowledge (TK)" is most associated with traditional medicine and botany, while "indigenous knowledge (IK)" is most associated with cultural issues and sustainable development, and "local knowledge (LK)" with environmental issues.
|
||||
The phrase "traditional cultural expressions" is used by WIPO to refer to "any form of artistic and literary expression in which traditional culture and knowledge are embodied. They are transmitted from one generation to the next, and include handmade textiles, paintings, stories, legends, ceremonies, music, songs, rhythms and dance."
|
||||
WIPO negotiates international legal protection of traditional cultural expressions through the Intergovernmental Committee on Intellectual Property and Genetic Resources, Traditional Knowledge, and Folklore (IGC). During the committee's sessions, representatives of indigenous and local communities host panels relating to the preservation of traditional knowledge.
|
||||
Leading international authority on Indigenous cultural and intellectual property, Australian lawyer Terri Janke, says that within Australian Indigenous communities (comprising Aboriginal and Torres Strait Islander peoples), "the use of the word 'traditional' tends not to be preferred as it implies that Indigenous culture is locked in time".
|
||||
|
||||
== Property rights ==
|
||||
18
data/en.wikipedia.org/wiki/Traditional_knowledge-1.md
Normal file
18
data/en.wikipedia.org/wiki/Traditional_knowledge-1.md
Normal file
@ -0,0 +1,18 @@
|
||||
---
|
||||
title: "Traditional knowledge"
|
||||
chunk: 2/4
|
||||
source: "https://en.wikipedia.org/wiki/Traditional_knowledge"
|
||||
category: "reference"
|
||||
tags: "science, encyclopedia"
|
||||
date_saved: "2026-05-05T03:13:00.402589+00:00"
|
||||
instance: "kb-cron"
|
||||
---
|
||||
|
||||
International attention has turned to intellectual property laws to preserve, protect, and promote traditional knowledge. In 1992, the Convention on Biological Diversity (CBD) recognized the value of traditional knowledge in protecting species, ecosystems and landscapes, and incorporated language regulating access to it and its use (discussed below). It was soon urged that implementing these provisions would require revision of international intellectual property agreements.
|
||||
This became even more pressing with the adoption of the World Trade Organization Agreement on Trade-Related Aspects of Intellectual Property Rights (TRIPs), which established rules for creating and protecting intellectual property that could be interpreted to conflict with the agreements made under the CBD. In response, the states who had ratified the CBD requested the World Intellectual Property Organization (WIPO) to investigate the relationship between intellectual property rights, biodiversity and traditional knowledge. WIPO began this work with a fact-finding mission in 1999. Considering the issues involved with biodiversity and the broader issues in TRIPs (involving all forms of cultural expressions, not just those associated with biodiversity – including traditional designs, music, songs, stories, etc.), WIPO established the Intergovernmental Committee on Intellectual Property and Genetic Resources, Traditional Knowledge and Folklore (IGC-GRTKF). WIPO Lex provides support for collections of laws concerning Traditional Knowledge.
|
||||
The period of the early 1990s to the Millennium was also characterized by the rapid rise in global civil society. The high-level Brundtland Report (1987) recommended a change in development policy that allowed for direct community participation and respected local rights and aspirations. Indigenous peoples and others had successfully petitioned the United Nations to establish a Working Group on Indigenous Populations that made two early surveys on treaty rights and land rights. These led to a greater public and governmental recognition of indigenous land and resource rights, and the need to address the issue of collective human rights, as distinct from the individual rights of existing human rights law.
|
||||
The collective human rights of indigenous and local communities has been increasingly recognized – such as in the International Labour Organization (ILO) Convention 169 (1989) and the Declaration on the Rights of Indigenous Peoples (2007). The Rio Declaration (1992), endorsed by the presidents and ministers of the majority of the countries of the world, recognized indigenous and local communities as distinct groups with special concerns that should be addressed by states.
|
||||
Initial concern was over the territorial rights and traditional resource rights of these communities. Indigenous peoples soon showed concern for the misappropriation and misuse of their "intangible" knowledge and cultural heritage. Indigenous peoples and local communities have resisted, among other things: the use of traditional symbols and designs as mascots, derivative arts and crafts; the use or modification of traditional songs; the patenting of traditional uses of medicinal plants; and the copyrighting and distribution of traditional stories.
|
||||
Indigenous peoples and local communities have sought to prevent the patenting of traditional knowledge and resources where they have not given express consent. They have sought for greater protection and control over traditional knowledge and resources. Certain communities have also sought to ensure that their traditional knowledge is used equitably - according to restrictions set by their traditions, or requiring benefit sharing for its use according to benefits which they define.
|
||||
Three broad approaches to protect traditional knowledge have been developed. The first emphasizes protecting traditional knowledge as a form of cultural heritage. The second looks at protection of traditional knowledge as a collective human right. The third, taken by the WTO and WIPO, investigates the use of existing or novel sui generis measures to protect traditional knowledge.
|
||||
Currently, only a few nations offer explicit sui generis protection for traditional knowledge. However, a number of countries are still undecided as to whether law should give traditional knowledge deference. Indigenous peoples have shown ambivalence about the intellectual property approach. Some have been willing to investigate how existing intellectual property mechanisms (primarily: patents, copyrights, trademarks and trade secrets) can protect traditional knowledge. Others believe that an intellectual property approach may work, but will require more radical and novel forms of intellectual property law ("sui generis rights"). Others believe that the intellectual property system uses concepts and terms that are incompatible with traditional cultural concepts, and favors the commercialization of their traditions, which they generally resist. Many have argued that the form of protection should refer to collective human rights to protect their distinct identities, religions and cultural heritage.
|
||||
35
data/en.wikipedia.org/wiki/Traditional_knowledge-2.md
Normal file
35
data/en.wikipedia.org/wiki/Traditional_knowledge-2.md
Normal file
@ -0,0 +1,35 @@
|
||||
---
|
||||
title: "Traditional knowledge"
|
||||
chunk: 3/4
|
||||
source: "https://en.wikipedia.org/wiki/Traditional_knowledge"
|
||||
category: "reference"
|
||||
tags: "science, encyclopedia"
|
||||
date_saved: "2026-05-05T03:13:00.402589+00:00"
|
||||
instance: "kb-cron"
|
||||
---
|
||||
|
||||
=== Public domain ===
|
||||
Literary and artistic works based upon, derived from or inspired by traditional culture or folklore may incorporate new elements or expressions. Hence these works may be "new" works with a living and identifiable creator, or creators. Such contemporary works may include a new interpretation, arrangement, adaptation or collection of pre-existing cultural heritage that is in the public domain. Traditional culture or folklore may also be "repackaged" in digital formats, or restoration and colorization. Contemporary and tradition based expressions and works of traditional culture are generally protected under existing copyright law, a form of intellectual property law, as they are sufficiently original to be regarded as "new" upon publication. Copyright protection is normally temporary. When a work has existed for a long enough period (often for the rest of the author's life plus an additional 50 to 70 years), the legal ability of the creator to prevent other people from reprinting, modifying, or using the property lapses, and the work is said to enter the public domain. Copyright protection also does not extend to folk songs and other works that developed over time, with no identifiable creators.
|
||||
Having an idea, story, or other work legally protected only for a limited period of time is not accepted by some indigenous peoples. On this point the Tulalip Tribes of Washington state has commented that "open sharing does not automatically confer a right to use the knowledge (of indigenous people)... traditional cultural expressions are not in the public domain because indigenous peoples have failed to take the steps necessary to protect the knowledge in the Western intellectual property system, but from a failure of governments and citizens to recognise and respect the customary laws regulating their use". Equally, however, the idea of restricting the use of publicly available information without clear notice and justification is regarded by many in developed nations as unethical as well as impractical.
|
||||
|
||||
== Indigenous intellectual property ==
|
||||
|
||||
Indigenous intellectual property is an umbrella legal term used in national and international forums to identify indigenous peoples' special rights to claim (from within their own laws) all that their indigenous groups know now, have known, or will know. It is a concept that has developed out of a predominantly western legal tradition, and has most recently been promoted by the World Intellectual Property Organization, as part of a more general United Nations push to see the diverse wealth of the world's indigenous, intangible cultural heritage better valued and better protected against probable, ongoing misappropriation and misuse.
|
||||
In the lead-up to and during the United Nations International Year for the World's Indigenous People (1993), and then during the following UN Decade of the World's Indigenous People (1995–2004), a number of conferences of both indigenous and non-indigenous specialists were held in different parts of the world, resulting in a number of declarations and statements identifying, explaining, refining, and defining "indigenous intellectual property".
|
||||
|
||||
=== Agreement on Trade-Related Aspects of Intellectual Property Rights (TRIPs) ===
|
||||
|
||||
Article 27. 3(b) of the Agreement on Trade-Related Aspects of Intellectual Property Rights (TRIPs) sets out certain conditions under which certain biological materials or intellectual innovations may be excluded from patenting. The Article also contains a requirement that Article 27 be reviewed. In the TRIPs-related Doha Declaration of 2001, Paragraph 19 expanded the review to a review of Article 27 and the rest of the TRIPs agreement to include the relationship between the TRIPS Agreement and the 1992 Convention on Biological Diversity (CBD) and the protection of traditional knowledge and folklore.
|
||||
|
||||
=== The Convention on Biological Diversity (CBD) ===
|
||||
|
||||
The Convention on Biological Diversity (CBD), signed at the United Nations Conference on Environment and Development (UNCED) in 1993, was the first international environmental convention to develop measures for the use and protection of traditional knowledge, related to the conservation and sustainable use of biodiversity. By 2006, 188 had ratified the Convention and agreed to be bound by its provisions, the largest number of nations to accede to any existing treaty (the United States is one of the few countries that has signed, but not ratified, the CBD). Significant provisions include:
|
||||
|
||||
Article 8. In-situ Conservation
|
||||
Each Contracting Party shall, as far as possible and as appropriate:
|
||||
(a)...
|
||||
(j) Subject to its national legislation, respect, preserve and maintain knowledge, innovations and practices of indigenous and local communities embodying traditional lifestyles relevant for the conservation and sustainable use of biological diversity and promote their wider application with the approval and involvement of the holders of such knowledge, innovations and practices and encourage the equitable sharing of the benefits arising from the utilization of such knowledge, innovations and practices...
|
||||
Article 10. Sustainable Use of Components of Biological Diversity
|
||||
Each Contracting Party shall, as far as possible and as appropriate:
|
||||
(a)...
|
||||
(c) Protect and encourage customary use of biological resources in accordance with traditional cultural practices that are compatible with conservation or sustainable use requirements
|
||||
48
data/en.wikipedia.org/wiki/Traditional_knowledge-3.md
Normal file
48
data/en.wikipedia.org/wiki/Traditional_knowledge-3.md
Normal file
@ -0,0 +1,48 @@
|
||||
---
|
||||
title: "Traditional knowledge"
|
||||
chunk: 4/4
|
||||
source: "https://en.wikipedia.org/wiki/Traditional_knowledge"
|
||||
category: "reference"
|
||||
tags: "science, encyclopedia"
|
||||
date_saved: "2026-05-05T03:13:00.402589+00:00"
|
||||
instance: "kb-cron"
|
||||
---
|
||||
|
||||
The interpretation of these provisions has been elaborated through decisions by the parties (ratifiers of the Convention) (see the Convention on Biological Diversity Handbook, available free in digital format from the Secretariat). Nevertheless, the provisions regarding Access and Benefit Sharing contained in the Convention on Biological Diversity never achieved consensus and soon the authority over these questions fell back to WIPO.
|
||||
At the Convention on Biological Diversity meeting, in Buenos Aires, in 1996, emphasis was put on local knowledge. Key players, such as local communities and indigenous peoples, should be recognized by States, and have their sovereignty recognised over the biodiversity of their territories, so that they can continue protecting it.
|
||||
The parties to the Convention set a 2010 target to negotiate an international legally binding regime on access and benefit sharing (ABS) at the Eighth meeting (COP8), 20–31 March 2006 in Curitiba, Brazil. This target was met in October 2010 in Nagoya, Japan, by conclusion of the Nagoya Protocol to the CBD. The agreement is now open for ratification, and will come into force when 50 signatories have ratified it. It entered into force on 12 October 2014. As of August 2020, 128 nations ratified the Nagoya Protocol. The Protocol treats of inter-governmental obligations related to genetic resources, and includes measures related to the rights of indigenous and local communities to control access to and derive benefits from the use of genetic resources and associated traditional knowledge.
|
||||
|
||||
== By region ==
|
||||
|
||||
=== Africa ===
|
||||
A decolonial outlook is present in African epistemology. Grounded in African ontology, it emphasizes the interconnectedness of reality as a continuum between knowing subject and known object. It understands knowledge as a holistic phenomenon that includes sensory, emotional, intuitive, and rational aspects, extending beyond the limits of the physical domain. Diminishment of traditional knowledge systems as 'myths' stems from Western academia historically dismissing African knowledge systems as superstition by portraying Africa as a "dark continent" – a place without history, culture or intellectual depth. There has been a favoring of a Eurocentric educational system in postcolonial times.
|
||||
|
||||
=== Australia ===
|
||||
In September 2020, the government of Queensland introduced the Biodiscovery and Other Legislation Amendment Act 2020, which introduced protections for accessing and using First Nations peoples' traditional knowledge in biodiscovery.
|
||||
|
||||
=== India ===
|
||||
|
||||
In 2001, the Government of India set up the Traditional Knowledge Digital Library (TKDL) as repository of 1200 formulations of various systems of Indian medicine, such as Ayurveda, Unani and Siddha and 1500 Yoga postures (asanas), translated into five languages – English, German, French, Spanish and Japanese. India has also signed agreements with the European Patent Office (EPO), United Kingdom Intellectual Property Office (UKIPO) and the United States Patent and Trademark Office (USPTO) to prevent the grant of invalid patents by giving patent examiners at International Patent Offices access to the TKDL database for patent search and examination.
|
||||
Some of the legislative measures to protect TK are The Biological Diversity Act (2002), The Protection of Plant Varieties and Farmers' Rights Act (2001) and The Geographical Indication of Goods (Registration And Protection) Act, 1999.
|
||||
The Intellectual Property Rights Policy for Kerala released in 2008 proposes adoption of the concepts 'knowledge commons' and 'commons licence' for the protection of traditional knowledge. The policy, largely created by Prabhat Patnaik and R.S. Praveen Raj, seeks to put all traditional knowledge into the realm of "knowledge commons", distinguishing this from the public domain. Raj has argued that TKDL cannot at the same time be kept confidential and treated as prior art.
|
||||
In 2016, Shashi Tharoor, Member of Parliament from Thiruvananthapuram introduced a Private Bill (the Protection of Traditional Knowledge Bill, 2016) codifying the "protection, preservation and promotion" of traditional knowledge system in India. However the bill was criticised for failing to address the real concern of traditional knowledge.
|
||||
|
||||
== In science and education ==
|
||||
How, if at all, to include indigenous knowledge in education and in relation to science has been controversial. It has been argued that indigenous knowledge can be complementary to science and includes empirical information, even encoded in mythological narratives, and that it holds equal educational value to science like the arts and humanities. Proponents also argue that its inclusion combats disillusionment among indigenous groups with the education system and helps to preserve their cultural identity. Studies indicate that if the introduction of TK into educational curriculums is to succeed, it would need to taught from the perspective of the relevant worldview, involve community participation, and have a bridge built between the national/dominant language and the indigenous one.
|
||||
Efforts to include it in education have been criticized on the grounds that it is inseparable from spiritual and religious beliefs; that it is not possible to reconcile contradictions between science and TK; that time spent on it comes at the cost of time delivering curricula that meets international academic standards; that policies granting science and indigenous knowledge equal status are based on relativism and inhibit science from questioning claims made by indigenous knowledge systems; and that some proponents of indigenous knowledge engage in ideological antiscience rhetoric.
|
||||
Traditional knowledge has been introduced into the curriculums in Zambia and Ethiopia among others. In countries like Angola, Ethiopia and Uganda there has been a renewed movement to indigenize African education. Scholars and educators have begun to appreciate the literacy and use of oral history to rebuild cultural identities. However even in these areas Indigenous knowledge, particularly about local plants and community practices, are often ignored in African science classrooms. Many teachers undervalue the cultural knowledge that students bring, reinforcing the divide between traditional and formal education. In New Zealand, an indigenous vitalist concept (mauri) was introduced into the national chemistry curriculum citing an 'equal status' policy, amid objections from science teachers. It was later removed from exam objectives after 18 months of controversy, though it still appeared in some materials afterwards.
|
||||
|
||||
== See also ==
|
||||
|
||||
== Notes ==
|
||||
|
||||
== References ==
|
||||
|
||||
== External links ==
|
||||
CBD Article 8(j): TradItional Knowledge, Innovations and Practices
|
||||
WTO: TRIPs Article 27.3b, traditional knowledge, biodiversity
|
||||
Statement by the Tulalip Tribes of Washington on Folklore, Indigenous Knowledge, and the Public Domain, July 09, 2003
|
||||
Intellectual Property Rights, Open Source Methods and Traditional Knowledge in Developing Countries
|
||||
Anti-colonial discourse and indigenous knowledges
|
||||
Traditional ecological knowledge handbook : a training manual and reference guide for designing, conducting, and participating in research projects using traditional ecological knowledge / prepared by Rita A. Miraglia. Hosted by Alaska State Publications Program.
|
||||
Research article by Terra Nuova on "Preservation and maintenance of biological diversity related knowledge of indigenous diversity and local communities with traditional lifestyles Bony Forest, Ijara District"
|
||||
44
data/en.wikipedia.org/wiki/Troughton_scale-0.md
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44
data/en.wikipedia.org/wiki/Troughton_scale-0.md
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|
||||
---
|
||||
title: "Troughton scale"
|
||||
chunk: 1/1
|
||||
source: "https://en.wikipedia.org/wiki/Troughton_scale"
|
||||
category: "reference"
|
||||
tags: "science, encyclopedia"
|
||||
date_saved: "2026-05-05T03:13:01.485380+00:00"
|
||||
instance: "kb-cron"
|
||||
---
|
||||
|
||||
The Troughton scale is a measurement scale that de facto served as the first national standard of length in the United States, from 1832 until 1856.
|
||||
|
||||
|
||||
== Physical description ==
|
||||
The measurement scale spans 82 inches and is subdivided to tenths of inches. It is marked on a silver inlay in a brass bar; the bar itself is about 86 inches long.
|
||||
|
||||
|
||||
== History ==
|
||||
The scale was prepared for the Office of Coast Survey by Troughton of London and was brought to the United States in 1815 by F. R. Hassler, who a year later became first Superintendent of the Survey of the Coast and, in 1832, first Superintendent of Weights and Measures.
|
||||
At the time, the United States Government was principally financed by duties on imports and exports (the federal income tax did not become a permanent feature of the US system until 1913). The appropriate import and export taxes on commercial items were determined at customhouses maintained by the federal government at various ports of entry. A reliable and uniform system of weights and measure was necessary for this system to work, as well as for settling commercial disputes.
|
||||
In 1830, the US Senate requested the Secretary of the Treasury to ‘cause a comparison to be made of the standards of weight and measure now used at the principal custom houses in the United States, and report to the Senate at the next session of Congress.’ To carry out this mandate, the Treasury Secretary appointed Hassler, who found that (as was suspected) large discrepancies existed among the weights and measures in use at the principal customhouses at different US ports.
|
||||
The Treasury Department immediately started constructing new necessary weights and measures for the customs service. For this purpose, the Treasury Department had to choose standards, and the standard yard adopted was the 36 inches comprised between the 27th and the 63rd inches of the Troughton scale. This 36-inch space was supposed to be identical with the English standard at 62 °F, though it had never been directly compared with that standard. The original English standard, in turn, was made in 1758, but was then damaged beyond the point of usability in the great fire of 1834.
|
||||
In 1856, the US received two copies of the new British standard yard after Britain completed the manufacture of new imperial standards to replace those lost in 1834. As standards of length, the new yards, especially bronze No. 11, were far superior to the Troughton scale. They were therefore accepted by the Office of Weights and Measures (a predecessor of NIST) as length standards of the United States.
|
||||
|
||||
|
||||
== Later developments ==
|
||||
The new standards were twice taken to England and recompared with the imperial yard, in 1876 and in 1888. Measurable discrepancies were found ‘which could not reasonably be said to be entirely due to changes in No. 11. Suspicion as to the constancy of the length of the British standard was therefore aroused.'
|
||||
In 1890, as a signatory of the Metre Convention, the US received two copies of the International Prototype Metre, the construction of which represented the most advanced ideas of standards of the time. Therefore it seemed that US measures would have greater stability and higher accuracy by accepting the international meter as fundamental standard, with the yard defined in terms of the meter. This was formalized in 1893 by the Mendenhall Order, with the conversion in accordance with the Metric Act of 1866 (as 1 meter = 39.37 inches, which corresponds to 1 inch = 2.5400051… centimeters). This value was adjusted in 1959 to its present value of 1 inch = 2.54 centimeters (or, 1 yard = 0.9144 meters), exactly.
|
||||
|
||||
|
||||
== Location ==
|
||||
As of 1965, the Troughton scale was stored in a case next to the Standards Vault at what was then the National Bureau of Standards (and is today NIST) in Washington, D.C.
|
||||
|
||||
|
||||
== References ==
|
||||
|
||||
|
||||
== See also ==
|
||||
Ferdinand Rudolph Hassler
|
||||
Standard (metrology)
|
||||
Yard
|
||||
Mendenhall Order
|
||||
National Institute of Standards and Technology
|
||||
Metrology
|
||||
88
data/en.wikipedia.org/wiki/Universal_science-0.md
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88
data/en.wikipedia.org/wiki/Universal_science-0.md
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|
||||
---
|
||||
title: "Universal science"
|
||||
chunk: 1/1
|
||||
source: "https://en.wikipedia.org/wiki/Universal_science"
|
||||
category: "reference"
|
||||
tags: "science, encyclopedia"
|
||||
date_saved: "2026-05-05T03:13:02.694505+00:00"
|
||||
instance: "kb-cron"
|
||||
---
|
||||
|
||||
Universal science (German: Universalwissenschaft; Latin: scientia generalis, scientia universalis) is a branch of metaphysics, dedicated to the study of the underlying principles of all science. Instead of viewing knowledge as being separated into branches, Universalists view all knowledge as being part of a single category. Universal science is related to, but distinct from, universal language.
|
||||
|
||||
|
||||
== Precursors ==
|
||||
Logic and rationalism lie at the foundation of the ideas of universal science. In a broad sense, logic is the study of reasoning. Although there were individuals that implicitly utilized logical methods prior to Aristotle, it is generally agreed he was the originator of modern systems of logic. The Organon, Aristotle's books on logic, details this system. In Categories, Aristotle separates everything into 10 "categories": substance, quantity, quality, relation, place, time, position, state, action, and passion. In De Interpretatione, Aristotle studied propositions, detailing what he determined were the most basic propositions and the relationships between them. The Organon had several other books, which further detailed the process of constructing arguments, deducing logical consequences, and even contained the foundations of the modern scientific method.
|
||||
The most immediate predecessor to universal science is the system of formal logic, which is the study of the abstract notions of propositions and arguments, usually utilizing symbols to represent these structures. Formal logic differs from previous systems of logic by looking exclusively at the structure of an argument, instead of at the specific aspects of each statement. Thus, while the statements "Jeff is shorter than Jeremy and Jeremy is shorter Aidan, so Jeff is shorter than Aidan" and "Every triangle has less sides than every rectangle and every rectangle has less sides than every pentagon, so every triangle has less sides than every pentagon" deal with different specific information, they are both are equivalent in formal logic to the expression
|
||||
|
||||
|
||||
|
||||
|
||||
∀
|
||||
x
|
||||
∈
|
||||
X
|
||||
,
|
||||
y
|
||||
∈
|
||||
Y
|
||||
,
|
||||
z
|
||||
∈
|
||||
Z
|
||||
,
|
||||
|
||||
x
|
||||
<
|
||||
y
|
||||
∧
|
||||
y
|
||||
<
|
||||
z
|
||||
|
||||
⟹
|
||||
|
||||
x
|
||||
<
|
||||
z
|
||||
|
||||
|
||||
{\displaystyle \forall x\in X,y\in Y,z\in Z,\quad x<y\wedge y<z\implies x<z}
|
||||
|
||||
.
|
||||
By abstracting away from the specifics of each statement and argument, formal logic allows the overarching structure of logic to be studied. This viewpoint inspired later logicians to seek out a set of minimal size containing all of the requisite knowledge from which everything else could be derived and is the fundamental idea behind universal science.
|
||||
|
||||
|
||||
== Llull ==
|
||||
|
||||
Ramon Llull was a 13th century Catalan philosopher, mystic, and poet. He is best known for creating an "art of finding truth" with the intention of unifying all knowledge. Llull sought to unify philosophy, theology, and mysticism through a single universal model to understand reality.
|
||||
Llull compiled his thoughts into his work Ars Magna, which had several versions. The most thorough and complete version being the Ars Generalis Ultima, which he wrote several years before his death. The Ars Generalis Ultima consisted of several books, which explained the Ars, his universal system to understand all of reality. The books included the principles, definitions, and questions, along with ways to combine these things, which Llull thought could serve as the basis from which reality could be studied. Since he was primarily focused upon faith and Christianity, the content of these books was also mainly concerned with religious ideas and concepts. In fact, the Ars contained figures and diagrams representing ideas from Christianity, Islam, and Judaism to serve as a tool to aid philosophers from each of the three religions to discuss ideas in a logical manner.
|
||||
|
||||
|
||||
== Leibniz ==
|
||||
Gottfried Wilhelm Leibniz was a 17th century German philosopher, mathematician, and political adviser, metaphysician, and logician, distinguished for his achievements including the independent creation of the mathematical field of Calculus.
|
||||
Leibniz entered the University of Leipzig in 1661, which is where he first studied the teachings of many famous scientists and philosophers, such as Rene Descartes, Galileo Galilei, Francis Bacon, and Thomas Hobbes. These individuals, together with Aristotle, influenced Leibniz's future philosophical ideas, with one major idea being the reconciliation of the ideas of modern philosophers with the thoughts of Aristotle, already demonstrating Leibniz's interest in unification.
|
||||
Unification played a major role in one of Leibniz's early works, Dissertatio de arte Combinatoria. Written in 1666, De arte Combinatoria was a mathematical and philosophical text that served as the basis for Leibniz's future goal for a universal science. The text starts by analysis several mathematical problems in combinatorics, the study of ways in which objects can be arranged. While the mathematics in the text was not revolutionary, the main impact came from the ideas Leibniz derived following the mathematics. Taking major influence from Ramon Llull's ideas in his Ars Magna, Leibniz argued that the solution to these combinatorial problems served as a base for all logic and reasoning, since all of human knowledge could be viewed as different permutations of some base set.
|
||||
Leibniz's ideas about unifying human knowledge culminated in his Characteristica universalis, which was a proposed language that would allow for logical statements and arguments to become symbolic calculations. Leibniz aimed to construct "the alphabet of human thought," which was the collection of all of the "primitives" from which all human thought could be derived through the processes described in de arte Combinatoria.
|
||||
|
||||
|
||||
== Modern Influences ==
|
||||
Although it has never been constructed, the ideas behind Leibniz's universal science have permeated the thoughts of many modern mathematics and philosophers. George Boole, a 19th century English mathematician, expanded upon the ideas of Leibniz. He is responsible for the modern symbolic system logic, aptly called Boolean Algebra. Boole's logical system, and thus also Leibniz's logical system, served as the foundation for modern computers and electronic circuitry.
|
||||
The fundamental ideas of universal science can also be seen in the modern axiomatic system of mathematics, which constructs mathematical theories as consequences of a set of axioms. In this case, axioms are the primitive elements from which all further propositions can be derived. Hilbert's Program was an attempt by German mathematician David Hilbert to axiomatize all of mathematics in the above manner, and additionally to prove that these axiomatic systems are consistent. Kurt Gödel was an Austrian mathematician and logician, who furthered the investigations in logic and the foundations of mathematics began by Hilbert and Russell in the early 20th century. Gödel is most famous for his incompleteness theorems, which encompass two theorems about provability and completeness of logical systems. In his first theorem, Gödel asserts that any formal system that includes arithmetic will have a statement which cannot be proven nor disproven within the system. His second theorem stated that a formal system additionally cannot prove that it is consistent, using methods only from that system. Thus, Gödel essentially refuted Hilbert's Program, along with aspects of universal science.
|
||||
|
||||
|
||||
== See also ==
|
||||
Architectonics
|
||||
Unified Science
|
||||
Universal Language
|
||||
Ars Magna
|
||||
Dissertatio de arte Combinatoria
|
||||
Characteristica universalis
|
||||
Mathesis universalis
|
||||
|
||||
|
||||
== References ==
|
||||
|
||||
|
||||
== External links ==
|
||||
Stephen Palmquist, Heading 6, Philosophy as the Theological Science
|
||||
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Reference in New Issue
Block a user