CBSE Book Class 11 Philosophy Categorical Syllogism

Categorical Syllogism

What is a syllogism?

Inference or reasoning is the process of passing from one or more propositions to another with some justification. This inference when expressed in language is called an argument. An argument consists of more than one proposition (premise and conclusion). The conclusion of an argument is the proposition that is affirmed on the basis of the other propositions of the argument. These other propositions which provide support or ground for the conclusion are called premises of the argument. Inferences have been broadly divided as deductive and inductive. A deductive argument makes the claim that its conclusion is supported by its premises conclusively. An inductive argument, in contrast, does not make such a claim. It claims to support its conclusion only with some degrees of probability. Deductive inferences are again divided into Immediate and Mediate.

Immediate inference is a kind of deductive inference in which the conclusion follows from one premise only. In mediate inference, on the other hand, the conclusion follows from more them one premise. Where there are only two premises, and the conclusion follows from them jointly, it is called syllogism.

A syllogism is a deductive argument in which a conclusion is inferred from two premises. The syllogisms with which we are concerned here are called categorical because they are arguments based on the categorical relations of classes or categories. Such relations are of three kinds.

1. The whole of one class may be included in the other class such as All dogs are mammals.

2. Some members of one class may be included in the other such as Some chess players are females.

3. Two classes may not have anything in common such as No man is perfect 

A categorical syllogism, thus, can be defined as a deductive argument consisting of three categorical propositions that together contain exactly three terms each of which occurs twice only.

Types of Syllogism

Before discussing the structure and rules of a valid syllogism, it is necessary to distinguish categorical Categorical Syllogism

(Table - 1)

In a categorical syllogism all propositions (both the premises and conclusion) are categorical propositions that is A, E, I and O. For example :

All men are mortal

All players are men

Therefore, all players are mortal

In a compound syllogism one premise or both the premises and conclusion are compound propositions.

If it rains in time, then the crops will be good.

If crops is good, inflation will be controlled.

Therefore, if it rains in time, then inflation will be controlled.

(i) In mixed hypothetical syllogism, the major premise is hypothetical, the minor premise is categorical and the conclusion is also categorical. We have two forms of this kind of syllogism known as Modus Ponens and Modus Tollens. These two kinds can be understood by the following examples:

(i) If you work hard then you will pass. You are working hard.

Therefore, you will pass.

This is an example of Modus Ponens where by affirming the antecedent we can affirm the consequent.

Please refer to the link below - CBSE Class 11 Philosophy Categorical Syllogism