---
title: "History of science"
chunk: 18/19
source: "https://en.wikipedia.org/wiki/History_of_science"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T03:38:18.549055+00:00"
instance: "kb-cron"
---

=== Applications ===
In terms of applications, a massive number of new technologies were developed in the 20th century. Technologies such as electricity, the incandescent light bulb, the automobile and the phonograph, first developed at the end of the 19th century, were perfected and universally deployed. The first car was introduced by Karl Benz in 1885. The first airplane flight occurred in 1903, and by the end of the century airliners flew thousands of miles in a matter of hours. The development of the radio, television and computers caused massive changes in the dissemination of information. Advances in biology also led to large increases in food production, as well as the elimination of diseases such as polio by Dr. Jonas Salk. Gene mapping and gene sequencing, invented by Drs. Mark Skolnik and Walter Gilbert, respectively, are the two technologies that made the Human Genome Project feasible. Computer science, built upon a foundation of theoretical linguistics, discrete mathematics, and electrical engineering, studies the nature and limits of computation. Subfields include computability, computational complexity, database design, computer networking, artificial intelligence, and the design of computer hardware. One area in which advances in computing have contributed to more general scientific development is by facilitating large-scale archiving of scientific data. Contemporary computer science typically distinguishes itself by emphasizing mathematical 'theory' in contrast to the practical emphasis of software engineering.
Einstein's paper "On the Quantum Theory of Radiation" outlined the principles of the stimulated emission of photons. This led to the invention of the Laser (light amplification by the stimulated emission of radiation) and the optical amplifier which ushered in the Information Age. It is optical amplification that allows fiber optic networks to transmit the massive capacity of the Internet.
Based on wireless transmission of electromagnetic radiation and global networks of cellular operation, the mobile phone became a primary means to access the internet.

=== Developments in political science and economics ===
In political science during the 20th century, the study of ideology, behaviouralism and international relations led to a multitude of 'pol-sci' subdisciplines including rational choice theory, voting theory, game theory (also used in economics), psephology, political geography/geopolitics, political anthropology/political psychology/political sociology, political economy, policy analysis, public administration, comparative political analysis and peace studies/conflict analysis. In economics, John Maynard Keynes prompted a division between microeconomics and macroeconomics in the 1920s. Under Keynesian economics macroeconomic trends can overwhelm economic choices made by individuals. Governments should promote aggregate demand for goods as a means to encourage economic expansion. Following World War II, Milton Friedman created the concept of monetarism. Monetarism focuses on using the supply and demand of money as a method for controlling economic activity. In the 1970s, monetarism has adapted into supply-side economics which advocates reducing taxes as a means to increase the amount of money available for economic expansion. Other modern schools of economic thought are New Classical economics and New Keynesian economics. New Classical economics was developed in the 1970s, emphasizing solid microeconomics as the basis for macroeconomic growth. New Keynesian economics was created partially in response to New Classical economics. It shows how imperfect competition and market rigidities, means monetary policy has real effects, and enables analysis of different policies.

=== Developments in psychology, sociology, and anthropology ===
Psychology in the 20th century saw a rejection of Freud's theories as being too unscientific, and a reaction against Edward Titchener's atomistic approach of the mind. This led to the formulation of behaviorism by John B. Watson, which was popularized by B.F. Skinner. Behaviorism proposed epistemologically limiting psychological study to overt behavior, since that could be reliably measured. Scientific knowledge of the "mind" was considered too metaphysical, hence impossible to achieve. The final decades of the 20th century have seen the rise of cognitive science, which considers the mind as once again a subject for investigation, using the tools of psychology, linguistics, computer science, philosophy, and neurobiology. New methods of visualizing the activity of the brain, such as PET scans and CAT scans, began to exert their influence as well, leading some researchers to investigate the mind by investigating the brain, rather than cognition. These new forms of investigation assume that a wide understanding of the human mind is possible, and that such an understanding may be applied to other research domains, such as artificial intelligence. Evolutionary theory was applied to behavior and introduced to anthropology and psychology, through the works of cultural anthropologist Napoleon Chagnon. Physical anthropology would become biological anthropology, incorporating elements of evolutionary biology.
American sociology in the 1940s and 1950s was dominated largely by Talcott Parsons, who argued that aspects of society that promoted structural integration were therefore "functional". This structural functionalism approach was questioned in the 1960s, when sociologists came to see this approach as merely a justification for inequalities present in the status quo. In reaction, conflict theory was developed, which was based in part on the philosophies of Karl Marx. Conflict theorists saw society as an arena in which different groups compete for control over resources. Symbolic interactionism also came to be regarded as central to sociological thinking. Erving Goffman saw social interactions as a stage performance, with individuals preparing "backstage" and attempting to control their audience through impression management. While these theories are currently prominent in sociological thought, other approaches exist, including feminist theory, post-structuralism, rational choice theory, and postmodernism.
In the mid-20th century, much of the methodologies of earlier anthropological and ethnographical study were reevaluated with an eye towards research ethics, while at the same time the scope of investigation has broadened far beyond the traditional study of "primitive cultures".