used in debate; and second, to understand all the different tests that may be applied to each to determine its validity. Basis of the Classification of Argument. The basis of classifying all argument rests upon the nature of the inference between the premises and the conclusion; and the nature of the inference depends upon the nature of the premises and of the conclusion. Argument is classified, therefore, according to the relation that exists between different types of premises and different types of conclusions. 1 Three Main Divisions of Argument. — Argument, like reason, may be divided into three main divisions: namely, 1. Argument by Deduction Argument by deduction consists in arguing from a general truth in a premise to a particular truth in the conclusion. Argument by induction consists in arguing from a particular truth or truths in the premises to a general truth in the conclusion. Argument by analogy consists in arguing from a particular truth in a premise to a similar particular truth in the conclusion. Sometimes these three types of argument are defined briefly as follows: Argument by deduction is argument from the general to the particular; argument by induction, from the particular to the general; and argument by analogy, from particular to particular. 1 See page 50. To illustrate the difference between these three main divisions of argument, the following examples are given of arguments by deduction, by induction, and by analogy. This argument is an example of argument by deduction, because the reasoning employed in it proceeds from a general truth in a premise all men are mortal to a particular truth in the conclusion Socrates was mortal. Induction I. All men are mortal; for This argument is an example of argument by induction, because the reasoning employed in it proceeds from a particular truth in each of the premises to a general truth in the conclusion. Analogy I. Socrates was mortal; for A. Plato was mortal; and B. Plato was just like Socrates. 1 This argument is an example of argument by analogy, because the reasoning employed in it proceeds from a particular truth in a premise — Plato was mortal to a similar particular truth in the conclusion - Socrates was mortal. Table of the Classes of Argument. A complete table of all the more important classes of argument employed in proof is given below: I. Argument by Deduction A. Formal Argument by the Syllogism 1. The Categorical Syllogism 2. The Disjunctive Syllogism 3. The Hypothetical Syllogism B. Informal Argument by the Enthymeme 2. Argument from Classification 4. Argument from Implied Causal Relationship II. Argument by Induction III. Argument by Analogy B. Figurative Analogy I. DEDUCTION Formal and Informal Argument by Deduction. - The first important division of argument by deduction distinguishes formal argument by means of the syllogism from informal argument by means of the enthymeme. Formal argument by means of the syllogism is an elaborate method of reasoning employed to show the complete struc ture of an argument; whereas, informal argument by means of the enthymeme is a simple method of reasoning employed in ordinary thought, speech, or composition. Though formal argu (A) Formal Argument by the Syllogism Importance of Formal Argument. ment is used less frequently in actual debate than informal argument, it is nevertheless an extremely important kind of argument for the debater to study; for all informal argument is capable of expansion into formal argument, with the result that whatever is implied in an informal argument is laid open to inspection in its expanded form. By means of such expansion, the debater can more easily test an informal argument for its validity. Formal argument, therefore, though less frequently used in actual debate than informal argument, is important; because it enables the debater to understand better all the different informal arguments. Nature of the Syllogism. The syllogism, as it appears in formal argument, is a method of reasoning that involves two premises used jointly: one being called the major premise and the other being called the minor premise. The major premise contains always a general law or principle to be applied in proof; and the minor premise contains always a statement of fact that shows the application of the general law or principle to the case in hand. By virtue of the major premise, all syllogisms are arguments by deduction. The Categorical Syllogism. The first type of formal argument to be considered is the categorical syllogism. This kind of syllogism derives its name from the fact that its conclusion and both its premises are categorical propositions. A categorical proposition is one that defines or classifies things. It consists always of a statement that something is, or is not; and in effect it states that something does, or does not, belong to a certain class of things. The categorical syllogism is founded on the process of classification. It advances to its conclusion by showing the relation between two things and a third thing, and thereby showing the relation that exists between the two things themselves. An example of the categorical syllogism is found in the following argument: I. Chicago is a public corporation; for 3 A. Chicago is a city; and B. All cities are public corporations. In this syllogism, the conclusion and both premises are categorical propositions. The second premise is the major premise, because it states the general law or principle to be applied in the proof; and the first premise is the minor premise, because it states the fact that shows the application of the general law or principle to the case in hand. The nature of the reasoning employed in a categorical syllogism may be illustrated best, perhaps, by reducing to a formula the argument given above. This argument would then appear in the following form: A is a C; for A is a B; and All B's are C's. Technical Terms Employed in the Categorical Syllogism. To understand the categorical syllogism, the debater must know what is meant by the major term; the minor term; the middle term; and a distributed term. The major term is always the term found in the predicate of the conclusion. This term is then found in one of the premises and gives its name to the premise. The minor term is always the |