Two Wrongs Make a Right

When you defend your wrong action as being right because someone previously has acted wrongly, you commit the fallacy called "two wrongs make a right." This is a kind of ad hominem fallacy.

Example:

Oops, no paper this morning. Somebody in our apartment building probably stole my newspaper. So, that makes it OK for me to steal one from my neighbor's doormat while nobody else is out here in the hallway.

Tu Quoque

The fallacy of tu quoque is committed if we conclude that someone's argument not to perform some act must be faulty because the arguer himself or herself has performed it. Similarly, when we point out that the arguer doesn't practice what he preaches, we may be therefore suppose that there must be an error in the preaching, but we are reasoning fallaciously and creating a tu quoque. This is a kind of ad hominem fallacy.

Example:

You say I shouldn't become an alcoholic because it will hurt me and my family, yet you yourself are an alcoholic, so your argument can't be worth listening to.

Discovering that a speaker is a hypocrite is a reason to be suspicious of the speaker's reasoning, but it is not a sufficient reason to discount it.

Traditional Wisdom

If you say or imply that a practice must be OK today simply because it has been the apparently wise practice in the past, you commit the fallacy of traditional wisdom. Procedures that are being practiced and that have a tradition of being practiced might or might not be able to be given a good justification, but merely saying that they have been practiced in the past is not always good enough, in which case the fallacy is committed. Also called argumentum consensus gentium when the traditional wisdom is that of nations.

Example:

Of course we should buy IBM's computer whenever we need new computers. We have been buying IBM as far back as anyone can remember.

The "of course" is the problem. The traditional wisdom of IBM being the right buy is some reason to buy IBM next time, but it's not a good enough reason in a climate of changing products, so the "of course" indicates that the fallacy of traditional wisdom has occurred.

Tokenism

If you interpret a merely token gesture as an adequate substitute for the real thing, you've been taken in by tokenism.

Example:

How can you call our organization racist? After all, our receptionist is African American.

If you accept this line of reasoning, you have been taken in by tokenism.