Final answer:
The tu quoque fallacy is when someone undermines an argument by pointing out hypocrisy on the part of the opponent, but a person's actions do not determine the strength or truth of their argument.
Step-by-step explanation:
The tu quoque fallacy is an ad hominem fallacy in which a person attempts to undermine an argument by pointing out hypocrisy on the part of the opponent. They imply that their opponent's past or current actions are inconsistent with their current argument. However, a person's actions do not determine the strength or truth of their argument. For example, if a teenager's father catches her smoking and reprimands her, and she responds with 'You did it too!', it does not make smoking any less dangerous. Smoking is inherently dangerous regardless of who is pointing it out.