Tu quoque fallacy

The Tu quoque fallacy (pronounced “too-kwo-kwee”), is a type of ad hominem fallacy that occurs when it is assumed that an argument is wrong because the person making the claim has previously spoken or acted in a way that is inconsistent with it (ie hypocrisy). The fallacy attacks the perceived hypocrisy of the person making the argument rather than the actual merits of the argument. Tu quoque is Latin for ‘you too’ and is also called the appeal to hypocrisy logical fallacy. The fallacy is used to avoid to engaging with the criticism of the argument by turning it back on the accuser: a criticism is answered with a criticism.

Expressed formally:
Person A makes a claim X.
Person B then asserts that A’s actions or past claims are not consistent with the truth of claim X.
Therefore X is false.

Examples:

• A: “smoking is a well known risk factor for cancer, so you should not smoke”; B: “but you smoke”
• a physiotherapist making a criticism of chiropractic might be defended by criticizing physiotherapy. The criticisms of physiotherapy may or may not be valid, but has nothing to do with the original criticism of chiropractic and could be considered a tu quoque fallacy
• “My cousin smoked during pregnancy and had no problems, therefore I will keep smoking”; despite the unequivocal evidence of the detrimental effects of smoking.
• X may have a belief about something else that Y disagrees with, so Y uses that when they are arguing about something unrelated.

Related Topics:
Ad hominem logical fallacy
‘Ad Hominem’ Print
‘Personal Attack ≠ Argument’ T-shirt
The Shill Gambit

Pick Your Logical Fallacy:

Ad hominem	Bandwagon fallacy	Cherry Picking	False Analogy	Galileo Gambit
Appeal to Authority Fallacy	Burden of Proof Fallacy	Confirmation Bias	False Balance	Natural Fallacy
Appeal to ignorance	False Equivalence	Slippery Slope Fallacy	False Dilemma or Dichotomy	Non sequitur
Appeal to Novelty Fallacy	Special pleading logical fallacy	Straw Man	Tautology	Post hoc ergo propter hoc
Appeal to Tradition Fallacy	The Moving Goalpost	Wishful Thinking Fallacy	Shill Gambit	Ambiguity Fallacy
Post Hoc Fallacy	Shoehorning	Motivated reasoning	Causal Illusions	Cognitive Biases
It's Just a Theory	Tu quoque fallacy	‘It worked for me’ Fallacy	Argument by Analogy	Sunk Cost
Critical Thinking Skills For Dummies	An Illustrated Book of Bad Arguments	The Critical Thinker's Dictionary: Biases, Fallacies, and Illusions and What You Can Do About Them	Logically Fallacious: The Ultimate Collection of Over 300 Logical Fallacies	Nonsense: Red Herrings, Straw Men and Sacred Cows: How We Abuse Logic in Our Everyday Language