A Collection of Strange Beliefs, Amusing Deceptions, and Dangerous Delusions

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From Abracadabra to Zombies - 767 entries | View All

The Skeptic's Dictionary features definitions, arguments, and essays on hundreds of strange beliefs, amusing deceptions, and dangerous delusions. It also features dozens of entries on logical fallacies, cognitive biases, perception, science, and philosophy.

  • Recent Entries or Modifications

for last month's changes see current Newsletter

Date           Status* Entry

31 July
revised self-deception

26 July
update the Trivedi effect

25 July
revised 9/11 conspiracies

21 July
revised dowsing

12 July
new Natural Thinking: (another) case study

09 July
New Skeptic's Dictionary Newsletter


Sample the Skeptic's Dictionary


....the usual meaning of 'self-deception' is 'the process or fact of misleading ourselves to accept claims about ourselves as true or valid when they are false or invalid.' Self-deception, in short, is a way we justify false beliefs about ourselves to ourselves. The most fundamental deception of human consciousness is the illusion of the existence of a self as an independent entity. The sense of self no more implies the existence of an independent entity than the sense of memory implies the existence of an independent entity called 'memory.' This belief in the self as an independent entity has led to many delusions regarding various kinds of spirits, such as souls that live on after the bodies they are thought to exist in are dead, ghoststhat haunt houses and communicate with celebrity mediums andelectronic devices, and exorcisms to relieve people of demons that are believed to possess them.>>more

sample Mysteries and Science (for kids 9 and up)

Clever Hans

In a nutshell: Clever Hans was a horse that some people thought could do math in his head and understand German. One group of people tested him and found these claims were true. Another scientist tested Hans and found the claims weren't true.

Clever Hans (German: Kluger Hans) was a German horse who seemed to be able to do math problems in his head, tell time, name people, and answer questions by tapping his hoof. When asked to add 3 + 2, Hans would tap his hoof five times. If asked my name, Hans would have tapped twice for 'B', paused, tapped 15 times for 'O', paused, and then tapped twice again.>>more

a blast from the past

Jamy Ian Swiss, TAM 2012, and Cognitive Incompetence

Date. 14 August 2012

Jamy Ian SwissLike many of you, I didn't attend TAM this year. I read several reviews of the event that praised the talk by Jamy Ian Swiss as "passionate," "inspiring," and "the best of the bunch." Orac posted a video of the talk. It's well worth the 30 or 40 minutes to listen to what Jamy has to say, but he hints in his talk that a Venn diagram could explain much of it much more simply and much more quickly. So, I whipped up the diagram using PowerPoint and Photoshop. Here it is; the explanation follows.>>more

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