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.


Sample the Skeptic's Dictionary

fluoridation of water

Extremely small amounts of fluoride in your saliva strengthen teeth by causing more minerals to enter teeth than leave them. Fluoride causes calcium phosphate crystals to form, which are incorporated into teeth as hard fluorhydroxyapatite. The amount of fluoride in your saliva needed to strengthen teeth is so minute that it does not change the bacterial content of your mouth or saliva. Fluoride prevents cavities only when it is in saliva all the time, so you need to get minute amounts regularly in your drinking water, toothpaste or mouthwash. --Gabe Mirkin, M.D.

The fluoridation of water supplies to municipalities in the U.S. is done to prevent tooth decay. There is little debate among scientists over the effectiveness and safety of fluoridation to fight cavities, but a small but vocal contrarian community has effectively blocked several cities from fluoridating by creating fear that the practice is unsafe and unnecessary. By 1950, enough scientific evidence existed to make the case that fluoridation at 1.0 ppm reduced children's cavities by 50%. In 1950, the United States Public Health Service recommended that communities without naturally occurring fluoride add it to their public water supplies at a concentration of 1.0 ppm. Despite the fact that doing so would mean a reduction in business for those dentists who filled the cavities of youngsters, the American Dental Association supported the policy.>>more

sample Mysteries and Science (for kids 9 and up)


In a nutshell: Rumpology is the study of rumps to find out about the owner's personality and to predict his future. There is no science that supports this idea.

Rumpology is the study of a person's rump to find out what kind of personality the rump owner has and to figure out what the future holds. I know this sounds like a joke. In fact, it is a joke to many people. But there are a few rumpologists out there, and they take their job as seriously as others who study the wrinkles on palms (palm reading) or faces (metoposcopy). You might laugh at the idea of the wrinkles, dimples, bumps, and birthmarks on a person's rump being important to who you are or what's going to happen to you in the future. If so, you should probably also laugh at those who use facial features (physiognomy) or the bumps and valleys on the skull (phrenology) to do the same thing that rumpologists do.>>more

a blast from the past

Rumpology for Dummies

Rumpology is the art of reading the lines, crevices, dimples, warts, moles, and folds on a client’s rump. It is analogous to palmistry and has the same purpose. You, the reader, will tell the client a few things about herself and what the future holds in store for her. The client can’t do this herself because she doesn’t have the expertise that you have. You don’t have any expertise, you say? That’s why you’re reading this how-to-article. I will give you all the expertise you’ll need. You’ll be amazed at how little you have to know in order to be a successful rumpologist.>>more


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