What is Tu Quoque (Logical Fallacy) in Rhetoric?

Tu quoque is a type of ad hominem argument in which an accused person turns an allegation back on his or her accuser, thus creating a logical fallacy. In the English language, the phrase generally functions as a noun, however, it's also used attributively to modify other nouns, as in "a tu quoque argument."

Example I

"It is clear that a tu quoque response to an accusation can never refute the accusation. Consider the following:

• Wilma: You cheated on your income tax. Don't you realize that's wrong
• Walter: Hey, wait a minute. You cheated on your income tax last year. Or have you forgotten about that?

Walter may be correct in his counter-accusation, but that does not show that Wilma's accusation is false."—From "Critical Thinking" by William Hughes and Jonathan Lavery

Example II

"Recently, we highlighted a British journalist’s story about the underside of Dubai’s startling ascent. Some in Dubai called foul, including one writer who wants to remind Britons that their own country has a dark side. After all, what to think of a country in which one-fifth of the population lives in poverty?"—From "Dubai’s Rebuttal," The New York Times, April 15, 2009

Example III

"The tu quoque fallacy occurs when one charges another with hypocrisy or inconsistency in order to avoid taking the other's position seriously. For example:

• Mother: You should stop smoking. It's harmful to your health.
• Daughter: Why should I listen to you? You started smoking when you were 16!

[Here], the daughter commits the tu quoque fallacy. She dismisses her mother's argument because she believes her mother is speaking in a hypocritical manner. While the mother may indeed be inconsistent, this does not invalidate her argument."—From "Informal Logical Fallacies: A Brief Guide" by Jacob E. Van Vleet

A Broader Definition of Tu Quoque 

"The tu quoque argument or 'you too' argument, according to the broader account, can be described as the use of any type of argument to reply in like kind to a speaker's argument. In other words, if a speaker uses a particular type of argument, say an argument from analogy, then the respondent can turn around and use that same kind of argument against the speaker, and this would be called a tu quoque argument . . .. So conceived, the tu quoque argument is quite a broad category that would include other types of argument as well as ad hominem arguments."—From "Ad Hominem Arguments" by Douglas N. Walton 

The Childish Response

"Of all human instincts, not even the urge to say 'I told you so' is stronger than the response called tu quoque: 'Look who's talking.' To judge from children, it is innate ('Cathy says you took her chocolate,' 'Yes but she stole my doll'), and we don't grow out of it . . .

"France has led calls for pressure to be put on the Burmese junta at the security council and through the EU, where foreign ministers discussed the issue yesterday. As part of the push, it has tried to enlist a recalcitrant Russia which, conscious perhaps of Chechnya, has no great wish to be seen criticizing anyone else's internal affairs. Hence a Russian minister's response that the next time there were riots in France he would refer the matter to the UN.

"This reply was at once childish, irrelevant, and probably very gratifying."—Geoffrey Wheatcroft, The Guardian, October 16, 2007

Sources

• Hughes, William; Lavery, Jonathan. "Critical Thinking," Fifth Edition. Broadview. 2008
• Van Vleet, Jacob E. "Informal Logical Fallacies: A Brief Guide." University Press of America. 2011
• Walton, Douglas N. "Ad Hominem Arguments." University of Alabama Press. 1998