Also Known as: "You Too Fallacy"
Description of Ad Hominem Tu Quoque
This fallacy is committed when it is concluded that a person's claim is false because 1) it is inconsistent with something else a person has said or 2) what a person says is inconsistent with her actions. This type of "argument" has the following form:
Person A makes claim X.
The fact that a person makes inconsistent claims does not make any particular claim he makes false (although of any pair of inconsistent claims only one can be true - but both can be false). Also, the fact that a person's claims are not consistent with his actions might indicate that the person is a hypocrite but this does not prove his claims are false.
Examples of Ad Hominem Tu Quoque
Jill: "I think the gun control bill shouldn't be supported because it
won't be effective and will waste money."
Bill: "But you are wearing a leather jacket and you have a roast beef sandwich in your hand! How can you say that using animals for food and clothing is wrong!"
"You shouldn't eat meat."