Lesson 18: Anecdotal Evidence

Spot the Faulty Logic #

“My grandpa smoked his whole life and lived to be 95, so smoking can’t be that dangerous.”

Discussion: Talk with your teacher about this example. What’s the problem with using this one story as proof?

How/Why It’s Often Used #

Stories are powerful and memorable. We naturally relate to personal experiences more than statistics or studies. When someone tells a vivid story about their own experience, it feels more real and convincing than abstract data.

This fallacy often appears in discussions about health, success, products, and practices. It’s easy to find one person whose experience supports almost any claim. People use anecdotes to argue for miracle cures, get-rich-quick schemes, and all kinds of beliefs.

Anecdotal Evidence in Action #

Did you spot the faulty logic? #

One person living long despite smoking doesn’t disprove the well-documented health risks. This grandfather might have had unusual genes, or other factors in his favor. The scientific evidence from millions of cases clearly shows smoking is dangerous, even if some individuals are exceptions.

Second Example #

“My friend dropped out of college and now she’s a millionaire. You don’t need an education to be successful!”

The Flaw #

One friend’s success doesn’t prove that dropping out is a good strategy in general. For every dropout who succeeds, many others struggle. We need to look at outcomes for many people, not just one memorable story.