An Introduction to Formal Logic

Abstract

Logic is the business of evaluating arguments, sorting good ones from bad ones. In everyday language, we sometimes use the word ‘argument’ to refer to bel- ligerent shouting matches. If you and a friend have an argument in this sense, things are not going well between the two of you. In logic, we are not interested in the teeth-gnashing, hair-pulling kind of ar- gument. A logical argument is structured to give someone a reason to believe some conclusion. Here is one such argument: (1) It is raining heavily. (2) If you do not take an umbrella, you will get soaked. .˙. You should take an umbrella.