Introduction to Logic

Part one is devoted to language, a modern discussion of the different functions of language is presented in its use in explaining the misleading character of certain informal fallacies. Part two, which deals with deductive logic, begins with three chapters, immediate inference, the categorical categorical syllogism , enthymemes, sorites, and dilemmas. Besides The Discussion Of Rules and fallacies , the Venn Diagram technique for testing categorical syllogism is presented. A more systematic treatment than usual is given to the problem of translating categorical syllogism from ordinary language into the standard forms to which the usual testing methods are applicable. Two also contains three chapters on symbolic logic, in which use its use in evaluating is stressed. The material presented here includes not only truth tables and the methods of formal proof by deduction, but also convenient methods of proving invalidity and enough theory of quantification to permit the symbolic treatment of categorical syllogism and even some asyllogistic but non-relational arguments. Part three, on inductive logic, begins with a more systematic treatment of argument by analogy than is usually accorded this frequently used and important type of inductive argument. In the separate chapter accorded to hypothesis as a method of science, the usually isolated topic of classification is incorporated as another example of the pervasive method of hypothesis. The Final chapter on probability includes an elementary treatment of the important topic of expectation, which is often omitted.