(IGP) IAS Pre Paper - 2: GS - Logical Reasoning & Analytical Ability - Syllogism

The word ‘Syllogism’ is also referred to ‘Logic’. Syllogism is an important section of logical reasoning and hence, a working knowledge of its rules is required on the part of the candidate. Hence, it can be expressed as the ‘Science of thought as expressed in language’. The questions based on syllogism can be solved by using Venn diagrams and some rules devised with the help of analytical ability. With this unique characteristic, this test becomes an instrument of teaching the candidates to follow the rules and work as per the instructions without an error. Here, only the basic concept and rules, which have a bearing on reasoning faculty could alone help. There are some terminology which are used in syllogism.

Proposition:

It is also referred to as ‘Premises’. It is a sentence which asserts that either a part of, or the whole of, one sets of objects-the set identified by the subject term in the sentence expressing that sentence either is included in, or is excluded from, another set-the set identified by the predicate term in that sentence.

Types of Proposition:

Categorical Proposition There is relationship between the subject and the predicate without any condition.

Example : I. All beams are logs.
II. No rod is stick.

Hypothetical Proposition: There is relationship between subject and predicate which is asserted conditionally.

Example : I. If it rains he will not come.
II. If he comes, I will accompany him.

Disjunctive Proposition In a disjunctive proposition the assertion is of alteration.

Example : I. Either he is brave or he is strong.
II. Either he is happy or he cannot take revenge.

Parts of Proposition:

It consists of four parts.

1. Quantifier: In quantifier the words, ‘all’, ‘no’ and ‘some’ are used as they express quantity. ‘All’ and ‘no’ are universal quantifiers because they refer to every object in a certain set. And quantifier ‘some’ is a particular quantifier because it refers to at least one existing object in a certain set.

2. Subject: It is the word about which something is said.
3. Predicate: It is the part of proposition which denotes which is affirmed or denied about the subject.
4. Copula: It is the part of proposition which denotes the relation between the subject and predicate.

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