Common Logical Fallacies

This is a short list of some logical fallacies that I encounter frequently when having discussions online. This does not mean they are the most common, most important, or have any particular thematic connection – they’re just what I personally notice. This page is starting out mostly as personal reference, but I expect to build it out over time. They are pulled from various sources, most of which are referenced on Argument and Debate References.

A quick note: having a list of words at hand is fun and can make you appear smart – to those who already agree with you (confirmation bias). Pointing out fallacies should be reserved for situations where it effectively removes an argument being raised so that you don’t have to spend time and space deconstructing and refuting the argument. For example, pointing out a strawman argument with a brief comment on why it’s a strawman should be sufficient – don’t continue addressing the argument itself in detail. Think of these fallacies as shorthand for pruning extraneous arguments and keeping the discussion on course, but try not to use them as arguments themselves.

I’ll start you off with a great post from Christie Anderson on patch.com.

Ten Commandments of Debate (source)

1. Thou shall not attack a person’s character but the argument itself. (“Ad hominem”)

2. Thou shall not misrepresent or exaggerate a person’s argument in order to make it easier to attack. (“Straw Man Fallacy)

3. Thou shall not use small numbers to represent the whole. (“Hasty Generalization”)

4. Thou shall not argue thy position by assuming one of its premises is true. (“Begging the Question”)

5. Thou shall not claim that because something occurred before, it must be the cause. (“Post Hoc/False Claim”)

6. Thou shall not reduce the argument down to two possibilities. (“Fake Dichotomy”)

7. Thou shall not argue that because of our ignorance that the claim must be true or false. (“Ad Ignorantiam”)

8. Thou shall not lay the burden of proof onto him who is questioning the claim. (“Burden of Proof Reversal”)

9. Thou shall not assume “this” follows “that” when “it” has no logical connection. (“Non Sequitor”)

10. Thou shall not claim that because a premises is popular, therefore, it must be true. (“Bandwagon Fallacy”)

Of these, I most frequently encounter ad hominem in many variations – typically used when trying to imply the argument you’ve presented has no merit because obviously you’re an idiot and nothing you say needs to be taken seriously. If this is brought up immediately in response to your argument, you have two options: review your own presentation and see if maybe they’re right; ignore them and move on because they won’t bother engaging with argument, no matter how logical, sound, and polite it is. When this happens, you are up against the fundamentalist. The only real benefit from this kind of exchange is in learning new ways to trade insults, which can be amusing.