Syllogism: Basic Concepts

The questions from the syllogism topic of reasoning comes almost in every competition exam. The difficulty level of syllogism questions in SSC exams is not so high. Almost all the SSC exams i.e CGL/CHSL/MTS/Steno. have the same quality of syllogism questions.

How to solve syllogism questions
There are mainly two types of Syllogism Questions namely: 2 - Statement Syllogism and 3 - Statement Syllogism questions. This article mainly focus on building the basics of syllogism questions. So let's just take a look at the format of the question.

Directions: In each of the following questions two statements followed by four conclusions (i), (ii), (iii) and (iv). Choose the conclusions which logically follow from the given statements.

Give answer:
(A) If only (i) conclusion follows
(B) If only (ii) conclusion follows
(C) If either (i) or (ii) follows
(D) If neither (i) nor (ii) follows and
(E) If both (i) and (ii) follow.

All books are chairs
All chairs are red

(i) All books are red.
(ii) Some red are books.

Basics of Syllogisms Questions 

1. Proposition: The two statements which are given above are called propositions. There are two things in any proposition i.e., 'Subject' and 'Predicate'.
  • Subject: The part about which something is being said. For eg. Books and Chairs. 
  • Predicate: The part of the proposition which tells us what is being said about the subject. For eg. chairs and red. 
Some More Examples:
  • All snakes are big.
  • No college boy is disciplined.
  • Some girls are beautiful.
Now in the above given examples snakes, college boy and girls are subjects and on the other hand big, disciplined and beautiful are predicate. 

2. Types of Proposition: There are mainly 2 types and they are:
  • Universal Proposition: These proposition either fully include the subject or fully exclude it. For eg, All boys are cute. Another example is None of the boys is honest. 
  • Particular Proposition: These proposition partly include or partly exclude the subject. Examples are. Some boys are cute..., Some boxes are broken. 
There is also sub-category of the above two categories. I am giving them with examples and also their shortcut name.
  • Universal Positive Proposition (A): All books are good. 
  • Universal Negative Proposition (E): No books are good.
  • Particular Positive Proposition (I): Some books are good.
  • Particular Negative Proposition (O): Some books are not good.