I'm trying to teach myself logic, using Suppes' Introduction to Logic, which seems to be a great book, but it unfortunately comes without any solutions to the exercises Well, and now I'm stuck with the following exercise:
"If one man is the father of a second, then the second is not father of the first. Therefore, no man is his own father." (or read it on google; I was able to solve most of them, except 3,4,9, and 10).
How do you solve that? Any help is greatly appreciated!