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

From Abracadabra to Zombies - 784 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.

Also posted are over 20 years of reader comments.

Click here for Index of all Reader Comments

  • Recent Entries or Modifications

Date           Status* Entry

22 May
new SD Newsletter

Sample the Skeptic's Dictionary

Marshall Vian Summers

Marshall SummersMarshall Summers has been claiming to be a prophet of some god who sends him messages via what he calls "the Angelic Presence." He says he's been a prophet since 1982 and has written down more than 9,000 pages of the usual spiritual pabulum, updated to fit the times with messages about saving the planet from ecological disaster and invasions of evil aliens in UFOs.>>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

Clever Irrationality






Many people pride themselves on being clever and equate their cleverness with rationality. For example, the "9/11 truthers" deny the reliability of the hundreds of eyewitnesses to a commercial airliner crashing into the Pentagon on September 11, 2001. The witnesses are all liars, part of the government conspiracy to make 9/11 look like the work of al-Qaeda terrorists. The "truthers" say a missile hit the Pentagon and all the debris of an airplane and body parts was faked. There's no evidence a missile hit anything. So what? The evidence was cleared away. There were passengers who got on an airplane that day, but they were whisked away and killed by government agents. The evidence? Prove it didn't happen! And so on ad nauseam. These folks who call themselves "truthers" are very clever but they're not very rational. A rational person will not call hundreds of people liars just to maintain their belief that a missile, not a passenger plane, hit the Pentagon. A rational person doesn't dismiss dozens of pieces of evidence that an airliner crashed into the Pentagon by simply denying the evidence is real. Dismissing evidence that doesn't fit with your beliefs isn't what a rational person does.>>more

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