Tu quoque is a fallacy that deflects criticism by accusing the accuser. You say I am wrong, but you are wrong too. The accusation is irrelevant. It does not address the original criticism. It changes the subject. It is a form of ad hominem. It is also called the appeal to hypocrisy.

The term is Latin for you too. The fallacy is common in arguments. A doctor tells a patient to quit smoking. The patient says, you smoke too. The doctor's habit is irrelevant. The advice is still sound. A politician is accused of corruption. The politician says, the other party is corrupt too. The other party's corruption is irrelevant. The accusation remains.

Tu quoque examples

• You say I should exercise, but you do not exercise.
• You criticize my spending, but you spend too.
• You tell me to recycle, but you do not recycle.
• You say I am late, but you were late last week.
• You say I am a hypocrite, but you are a hypocrite too.

Tu quoque is a fallacy of relevance. The hypocrisy of the accuser does not affect the truth of the accusation. A smoker can correctly say that smoking is harmful. A corrupt politician can correctly say that corruption is wrong. The message is separate from the messenger. That is the principle. In practice, hypocrisy is relevant to credibility. If a person does not follow their own advice, we trust them less. But credibility is not truth. The accusation stands or falls on the evidence. Tu quoque avoids the evidence. It attacks the accuser. It is a deflection. It is a fallacy. The original criticism remains. It must be answered.