Sunday, April 4, 2010

Logical Fallacies 2.0

Here are a few more fallacies of logic with which you should familiarize yourself. The better you know the various forms of logical fallacies, the less likely you'll ever be tripped up by them--in your own or in anyone else's writing.

Either/Or Fallacy
Claiming there are only two alternatives when there are more than two available. Either we continue using fossil fuels and destroy the earth, or we ban all fossil fuels forever. Never mind that there are many more possibilities beyond these two options.

Post Hoc, Ergo Propter Hoc
After this, therefore because of this. Arguing that since one event happened after another, the first event must have caused the second event. Since our mayor began his term two months ago, violent crime fell 15%.

Fallacy of the Loaded Question
Asking a question that implies something not known to be true. The classic example: When did you stop beating your wife?

False Generalization
A statement made based on no supporting evidence. Women are unable to do math and science. John will be a great student council president because everybody likes him.

Circular Logic
Making an assertion that is based on a restatement of a prior point. The police could not have roughed up the suspect because a police officer would never do something like that. Often referred to as begging the question.

Non Sequitur
Latin for it does not follow, and a general term for all types of fallacies of logic. Each of the fallacies described in this post is a non-sequitur of one form or another.