“Tu quoque” means “you too.” This tactic relies on shifting the focus of an argument from its independent merits to the number of people who subscribe to it. There are two ways to misrepresent an argument with this method.

A recent commercial encouraged people to take nutritional supplements. It showed several virile people of differing ages and backgrounds, each asserting that they took supplements. The voice-over then sprang into action: “180 million Americans take a nutritional supplement,” it said. This “appeal to popularity” approach is an attempt to support a claim with the fact that many other people already do it. It relies on the listener to make two false assumptions: 1) that others share the same purposes and lifestyles. (It would certainly be noteworthy if many experts on a subject subscribed to a practice (like nutritionists in the supplement example)). However, one should be wary of large numbers with no specification of the details behind them. And 2) that popularity makes something right. (Slavery was once popular, too.)

The second type of tu quoque argument is one that essentially says “two wrongs make a right.” This is the type of thinking that has robbed the U.S. of much of its global credibility on humanitarian issues in the recent past. When the U.S. claims that other countries are abusing human rights, those countries often counter that the U.S. has also played party to torture and the dubious imprisonment of internationals. Although those countries’ accusations are correct, the fact that the U.S. commits abuses does not justify their own abuses.

In either case where a tu quoque argument is used, you must look past who is doing something and find out why.