In my logic book, I’m encountering all sorts of familiar errors that I have committed in the past, and it’s been pretty fun reading!
Arguments have all sorts of errors when one is not acquainted with logic. Observe.
Mother: “You need to stop smoking. It is very bad for you.”
Son: “You did it too when you were my age!”
This is an example of the informal fallacy “tu quoque,” Latin for “you also.” It is when someone is engaged in an argument and points out that their opponent does or has done the same thing that they were accused of, in the hopes of defending himself. Even if it is true that your opponent has done the same thing, it does not help your position as whether or not someone else has done what you are doing does not affect your situation.
As a small child, I would occasionally refute one of my mother’s arguments with a prompt, “Everybody else is doing it, too!” feeling quite proud of myself for making such a great argument. Until, that is, my mom asked, “So?” In fact, most of our family made that argument as children, only to realize that it didn’t work very well.
And now I’ve learned that this is, apparently, a very common logical error!