The Lagoon TechMy little blog in Cyberspace.

This logical fallacy is known as “appeal to anecdote” (also known as an “argument from anecdote”). What exactly is “anecdotal evidence”? It is someone’s personal testimony of a particular event. It contains no scientific data, just someone’s word on a matter.

When you read someone’s anecdote and use it as proof, you would be committing the “appeal to anecdote” fallacy. You are saying something is true, just because someone else claims that is the case.

The Internet is full of people who give anecdotal testimonies as “proof” of their claims. Unless you were there with the person at the time of the event, or they present detailed evidence, there is no way to determine if they are accurately recalling the facts. This is assuming the person is telling the truth to begin with.

Here is an example. You go to a website to view information about the common cold. While on there, you decide to read the comment section.

A guy named Phil posts a comment saying he is a “very healthy individual” and “has never caught a cold before”. (Now personally I would say Phil is lying. Sure, there is a (very) small chance of his statement being true, but I would not bet on it.)

You take Phil’s comment and start going around telling others “there are people who can never get the common cold”. You would be committing the “appeal to anecdote” fallacy. You are saying something is true, because someone else claimed that is what happened to them.

Phil’s comment was not “proof” of anything. He presented no evidence of his claim. He could have had a cold (multiple times) and thought it was just allergies. If that is the case, he is relaying incorrect information based upon a bad assumption…and now you are relaying his bad information, based upon his bad assumption too. What a situation to be in!

Something to keep in mind. People are not talking face to face when using web forums, instant messaging, posting a comment, etc. That fact tends to make people feel more comfortable exaggerating information – or just plain making up information – about themselves or others in their anecdotes. No one is around to verify their information, much less “punish” them for lying.

This happens a whole lot more on the Internet than people realize, especially if the anecdote someone gives strokes their own ego (e.g., Someone claims they made $20,000 trading stocks. However, the person only made $6,000 trading stocks, not $20,000).

Always verify information you receive online (when possible) and use common sense when reading someone’s anecdote. Not everyone lies on the Internet, but it sure makes it a whole lot easier for the ones that do to get away with it.

Summary: An anecdote is someone’s personal testimony of a particular event. Using an anecdote to prove a point is a logical fallacy, since there is no evidence given, just someone’s word on a matter.