PP201 Lecture Notes - Rationalis, Logical Connective, Modus Tollens
Document Summary
Previously we noted that there are two basic categories of reasoning, namely, deductive and inductive. Over the next two weeks we"ll look at each of these categories in turn, beginning with deductive reasoning. To recapitulate the main points already mentioned about deductive reasoning: If one statement, c, strictly or logically follows from a set of statements, e. g. , consisting of a and b , then c is said to be deduced from a and b. We say that we can infer (deductively) c from a and b. A way of understanding the strict or logical nature of deductive inference is to understand it as mechanical. The inference in this sense can be calculated and as such it can be done by machine, just as we calculate in arithmetic. So long as a machine works, the rules designed into it, i. e. , the ways its procedures are designed to be executed, will invariably be followed. Let"s look at an example of deductive inference:
