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Scientific skepticism

Scientific skepticism (UK spelling, scepticism) sometimes referred to as skeptical inquiry, is a scientific, or practical, epistemological position (or paradigm) in which one does not accept the veracity of claims unless they can be scientifically verified.

This article does not deal with philosophical skepticism which is the school of thought in which one critically examines whether the knowledge and perceptions one has are true, and whether or not one can ever be said to have true knowledge.

For the sake of brevity, skepticism in the remainder of this article refers exclusively to scientific skepticism.



Skeptics do not rely on faith, but instead look for ways in which claims can be verified or falsified. Popular topics of criticism among skeptics include dowsing, astrology, alien abductions, ESP and other psychic powers, which skeptics allege are pseudosciences. Skeptics such as James Randi have become famous for debunking claims related to some of these. Many self-professed skeptics are atheists or agnostics, and have a naturalistic worldview, but Martin Gardner is an example of a committed skeptic with a religious world-view.

The following is a definition of scientific skepticism from Skeptic magazine:

What does it mean to be a skeptic? Some people believe that skepticism is rejection of new ideas, or worse, they confuse skeptic with cynic and think that skeptics are a bunch of grumpy curmudgeons unwilling to accept any claim that challenges the status quo. This is wrong. Skepticism is a provisional approach to claims. It is the application of reason to any and all ideas—no sacred cows allowed. In other words, skepticism is a method, not a position. Ideally, skeptics do not go into an investigation closed to the possibility that a phenomenon might be real or that a claim might be true. When we say we are skeptical, we mean that we must see compelling evidence before we believe. Skeptics are from Missouri, the "show me" state. When we hear a fantastic claim we say, "that's nice, prove it."...Modern skepticism is embodied in the scientific method, that involves gathering data to formulate and test naturalistic explanations for natural phenomena. A claim becomes factual when it is confirmed to such an extent it would be reasonable to offer temporary agreement. But all facts in science are provisional and subject to challenge, and therefore skepticism is a method leading to provisional conclusions. Some claims, such as dowsing, ESP, and creationism, have been tested (and failed the tests) often enough that we can provisionally conclude that they are not valid. Other claims, such theories concerning the origins and dissemination of language, gravity waves, or the diet of Tyrannosaurus Rex of have been tested but results are inconclusive, so we continue formulating and testing hypotheses and theories until we can reach a less provisional conclusion.

From a scientific point of view, theories are judged on many criteria, such as falsifiability, Occam's Razor, and explanatory power, as well as the degree to which their predictions match experimental results. A certain skepticism is part of the scientific method; for instance an experimental result is not regarded as established until it can be shown to be repeatable.

Famous skeptics

Danger of pseudoscience

Fundamentally, skepticism is an approach to new claims where doubt is preferred to belief, given a lack of conclusive evidence. This is a personal principle -- it does not, on the surface, imply that skeptics should attempt to convert other people to their beliefs. The question is often asked: what is the danger of "magical thinking" and pseudoscience? It may be silly to believe in UFOs and psychic powers, but why not tolerate those beliefs? What harm do they do?

The Ancient Greek philosopher Plato believed that to release another person from ignorance despite their initial resistance is a great and noble thing. Modern skeptical writers address this question in a variety of ways.

James Randi, for instance, often writes on the issue of fraud. On a case by case basis, he attempts to show how some promoters of pseudoscience make money from their claims, while secretly knowing them to be false. This is generally known as a "profit motive". Critics of alternative medicine often point to bad advice given by unqualified practitioners, leading to serious injury or death. Richard Dawkins points to religion as a source of violence, and considers creationism a threat to biology.

Related to this is the argument that many people who call themselves skeptics are not really skeptics, but rather "pseudo-skeptics" or, by a sneering redefinition of the term, "debunkers". Greg Taylor of Phenomena magazine sarcastically writes:

The first step in becoming a debunker is to immediately relinquish that title and establish your credentials by calling yourself either a skeptic or a scientist. Never mind that you are actually trying to impose your personal viewpoint on others, rather than following the scientific process and applying critical thinking to all sides of the argument. Actually, the best debunkers are those that don't even know their true identity, having such poor critical thinking skills that they truly believe that that they are exhibiting all the open-mindedness and mental sharpness of the true skeptic or scientist.

The wiki process being what it is, you may find elements of this point of view scattered throughout this article. Michael Shermer defends the term "debunker" in his January 2004 column in Scientific American:

Those of us who practice skepticism for a living often find ourselves tiptoeing politely around the PC police, who think that all beliefs and opinions are equal. Thus, when asked, "Are you a debunker?" my initial instinct is to dissemble and mutter something about being an investigator, as if that will soften the blow. But what need, really, is there to assuage? According to the Oxford English Dictionary, to debunk is to "remove the nonsense from; to expose false claims or pretensions." Bunk is slang for "humbug," and bunkum is "empty claptrap oratory."

By the principles of skepticism, the ideal case is that every individual should make their own mind up on the basis of the evidence, rather than appealing to some authority skeptical or otherwise.


Some critics of skepticism are known for supporting alleged pseudoscience, alien-related explanations of UFOs, psychic powers, and for favoring paranormal, if not supernatural, explanations of certain events. Self-described skeptics almost always favor established, consensus science and normally would reject any claim to the status of skeptic by anyone indulging in the above-mentioned beliefs, though religious belief (eg as in the case of Martin Gardner) seems to be allowable, perhaps because they are often explicitly based on faith. A common criticism of skepticism therefore is that it is, in effect, not an epistemological position at all, but a belief system which rejects certain alleged phenomena as real possibilities. Another critical sally is to point out that epistemological positions cannot themselves be scientifically verified; this line of thought can lead to robust forms of skepticism as exemplified by Hume, Quine, Descartes and other philosophical skeptics.

Critics of skepticism often point to cases where a scientific theory met a great deal of criticism before eventually being accepted. Commonly cited are Galileo's belief in heliocentric theory; the myth that Christopher Columbus' contemporaries thought the Earth was flat; Alfred Wegener's theory of continental drift, and skepticism towards rocks falling down to Earth. Thomas Jefferson himself commented: "I would more easily believe that two Yankee professors would lie, than that stones would fall from heaven."

While continental drift was opposed by young-earth creationists who believe in a young earth in which there would not be enough time for continental drift to occur, the significant opposition came from scientists on the grounds that Wegener's proposed mechanism to explain continental drift clearly could not work, and that no alternative seemed to be at hand.

Another example of this is the oft-cited case of meteorites; while some have argued that they were not accepted because the evidence for them was not good, opposition continued long after a number of reliable reports and even after Ernst Chladni showed that meteorites were geologically distinct from terrestrial rocks; what was apparently lacking was not evidence but a theoretical basis which made the evidence seem worthy of acceptance. These observation were not in agreement with the prevailing scientific thought. When the reasons why rocks falling from the sky was, later, proven not only logical but predictable, the question resolved itself. Critics of scientific skepticism assert that the skeptical mindset may cause difficulty harmonizing observation with established beliefs.

The arguments of critics are often coupled to the assertion that some particular present-day theory is being unduly criticised, and its proponents vilified. According to the sci.skeptic FAQ:

People putting forward extraordinary claims often refer to Galileo as an example of a great genius being persecuted by the establishment for heretical theories. They claim that the scientific establishment is afraid of being proved wrong, and hence is trying to suppress the truth.
This is a classic conspiracy theory. The Conspirators are all those scientists who have bothered to point out flaws in the claims put forward by the researchers.
The usual rejoinder to someone who says "They laughed at Columbus, they laughed at Galileo" is to say "But they also laughed at Bozo the Clown."

On occasion, not immediately accepting a new claim can be problematic. Ignaz Semmelweis's innovations in hygiene in the 1840s were ridiculed by a skeptical medical establishment; however, Semmelweis did not help his case with his refusal to publish his own data on the matter until years later. Many thousands of women continued to die unnecessarily in childbirth until cross contamination was indisputably confirmed by others.

In most cases however, skeptics do not see an occasional error as a flaw in skepticism -- they maintain that skepticism is a self-correcting system, and that with substantial evidence, any true skeptic would be more than happier to change their mind.

In history, this has not always been the case -- what is "substantial evidence" to one skeptic may be dismissed as trash by another. In science, the historian Thomas Kuhn attempted to create a model of how radical theory and worldview change occurred, what he called a "paradigm shift." Because of the often flexible nature of scientific observations, the illusive quality of nature, and the humanity of the actors involved, scientific change has rarely been a simple process of logical proofs and acceptances. The physicist Max Planck gestured towards the often personal aspect of scientific change:

An important scientific innovation rarely makes its way by gradually winning over and converting its opponents [...] What does happen is that its opponents gradually die out, and that the growing generation is familiarised with the idea from the beginning.

See also





External links


  • The Skeptic Society , Altadena, CA.
    • Promoting science & critical thinking and the investigation of extraordinary claims and revolutionary ideas.
  • Committee for the Scientific Investigation of Claims of the Paranormal , Amherst, NY. (
    • Investigation of paranormal and pseudoscience claims.


  • Carroll, Robert Todd, "The Skeptic's Dictionary ". New Jersey: John Wiley & Sons. 2003.
    • Collection of beliefs, deceptions, and delusions.
  • "Skepticism ". Creative Marketeam Canada Ltd. (
    • Philosophical systems and doctrines education.
  • sci.skeptic FAQ
    • Topics that are commonly discussed in the newsgroup sci.skeptic news://sci.skeptic (page is outdated)
  • Boerner, Rochus, "Some notes on Skepticism ". 2003.
    • Delineating skeptics, disbelievers, nonbeliever, and pseudoskeptics.
  • Hyman, Ray, "Proper Criticism ". (
    • Suggestions to upgrade the quality of Scientific skepticism
  • Martin, Brian, "Strategies for dissenting scientists ". Society for Scientific Exploration. Journal of Scientific Exploration, Volume 12 No 4. 1998. (PDF)
    • Strategies available for dissenting scientists.
  • Paine, Michael, , "Carl Sagan's Baloney Detection Kit ". Operation Clambake. 1998.
    • Based on the book "The Demon Haunted World: Science as a candle in the dark". (ISBN 0345409469)


  • Sofka, Michael D., "The Myths of Skepticism ". March 20, 2002.
    • written by a skeptic, "debunks" myths and views of skeptics.
  • Milton, Richard, "Scientific skepticism ".
    • (Main page)
    • Essay over "scientific discovery". (Alternative


  • Taylor, Greg, "Phenomena ".
Last updated: 02-09-2005 10:59:16
Last updated: 05-03-2005 17:50:55