Philosophy 111

hat is logic about? * Logic is about reasoning, i.e., about the way we infer one thing from another. * More specifically, logic deals with correct reasoning, and explains why certain forms of inference are correct while other forms are not. That is, it studies the abstract forms, the structures of reasoning that are used in argumentation. * More explicitly, logic evaluates arguments. But what is an argument? * In English, the terms 'argument' and 'arguing' are frequently used in a way that is slightly different from the one we'll be using in this class. * Generally we use the term 'argument' to refer to a dispute or disagreement and 'arguing' to refer to the activity of disagreeing. The two ways of using the terms, while different, are not entirely unrelated, for when we are involved in disagreement or dispute, we often try to show that our position is correct by stating evidence to support it. * In dealing with problems of logic and reasoning, the word 'argument' most commonly refers to a set of sentences related in such a way that some of the sentences purport to provide evidence for one of the sentences, without any suggestion of dispute or disagreement. * More specifically, an argument is a set of sentences consisting of one or more premises (the starting assumptions) and a conclusion, which is supposed to follow from the premises. * A sentence (or declarative sentence) is a statement that can be true or false. * Intuitively, a good argument gives the premises as reasons for believing the conclusion. Varieties of arguments * Rather artificially, arguments where the premise don't fully guarantee the conclusion, but make it likely or probable are called inductive (or even abductive) arguments. That is, inductive or abductive arguments only provide a partial degree of support for the conclusion (e.g., empirical sciences, etc.) * By contrast, arguments where the truth of the premises is