---
title: "History of pseudoscience"
chunk: 1/2
source: "https://en.wikipedia.org/wiki/History_of_pseudoscience"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T03:40:14.450688+00:00"
instance: "kb-cron"
---

The history of pseudoscience is the study of pseudoscientific theories over time. A pseudoscience is a set of ideas that presents itself as science, while it does not meet the criteria to properly be called such.
Distinguishing between proper science and pseudoscience is sometimes difficult. One popular proposal for demarcation between the two is the falsification criterion, most notably contributed to by the philosopher Karl Popper. In the history of pseudoscience it can be especially hard to separate the two, because some sciences developed from pseudosciences. An example of this is the science chemistry, which traces its origins from the protoscience of alchemy.
The vast diversity in pseudosciences further complicates the history of pseudoscience. Some pseudosciences originated in the pre-scientific era, such as astrology and acupuncture. Others developed as part of an ideology, such as Lysenkoism, or as a response to perceived threats to an ideology. An example of this is creationism, which was developed as a response to the scientific theory of evolution.
Despite failing to meet proper scientific standards, many pseudosciences survive. This is usually due to a persistent core of devotees who refuse to accept scientific criticism of their beliefs, or due to popular misconceptions. Sheer popularity is also a factor, as is attested by astrology which remains popular despite being rejected by a large majority of scientists.

== 19th century ==

Among the most notable developments in the history of pseudoscience in the 19th century are the rise of Spiritualism (traced in America to 1848), homeopathy (first formulated in 1796), and phrenology (developed around 1800). Another popular pseudoscientific belief that arose during the 19th century was the idea that there were canals visible on Mars. A relatively mild Christian fundamentalist backlash against the scientific theory of evolution foreshadowed subsequent events in the 20th century.
The study of bumps and fissures in people's skulls to determine their character, phrenology, was originally considered a science. It influenced psychiatry and early studies into neuroscience. As science advanced, phrenology was increasingly viewed as a pseudoscience. Halfway through the 19th century, the scientific community had prevailingly abandoned it, although it was not comprehensively tested until much later.
Halfway through the century, iridology was invented by the Hungarian physician Ignaz von Peczely. The theory would remain popular throughout the 20th century as well.

Spiritualism (sometimes referred to as "Modern Spiritualism" or "Spiritism")  or "Modern American Spiritualism" grew phenomenally during the period. The American version of this movement has been traced to the Fox sisters who in 1848 began claiming the ability to communicate with the dead. The religious movement would remain popular until the 1920s, when renowned magician Harry Houdini began exposing famous mediums and other performers as frauds (see also Harry Houdini#Debunking spiritualists). While the religious beliefs of Spiritualism are not presented as science, and thus are not properly considered pseudoscientific, the movement did spawn numerous pseudoscientific phenomena such as ectoplasm and spirit photography.
The principles of homeopathy were first formulated in 1796, by German physician Samuel Hahnemann. At the time, mainstream medicine was a primitive affair and still made use of techniques such as bloodletting. Homeopathic medicine by contrast consisted of extremely diluted substances, which meant that patients basically received water. Compared to the damage often caused by conventional medicine, this was an improvement. During the 1830s homeopathic institutions and schools spread across the US and Europe. Despite these early successes, homeopathy was not without its critics. Its popularity was on the decline before the end of the 19th century, though it has been revived in the 20th century.
The supposed Martian canals were first reported in 1877, by the Italian astronomer Giovanni Schiaparelli. The belief in them peaked in the late 19th century, but was widely discredited in the beginning of the 20th century.
The publication of Atlantis: The Antediluvian World by politician and author Ignatius L. Donnelly in 1882, renewed interest in the ancient idea of Atlantis. This highly advanced society supposedly existed several millennia before the rise of civilizations like Ancient Egypt. It was first mentioned by Plato, as a literary device in two of his dialogues. Other stories of lost continents, such as Mu and Lemuria also arose during the late 19th century.
In 1881 the Dutch Vereniging tegen de Kwakzalverij (English: Society against Quackery) was formed to oppose pseudoscientific trends in medicine. It is still active.