Syllogisms - Reasoning for SSC
What are Syllogisms?
Syllogism = Logical reasoning from two statements (premises) to reach a conclusion.
Format
Statements:
- All A are B
- All B are C
Conclusions: I. All A are C → Follows II. Some C are A → Follows
Types of Statements
- Universal Positive (A): All A are B
- Universal Negative (E): No A is B
- Particular Positive (I): Some A are B
- Particular Negative (O): Some A are not B
Venn Diagram Method
Best method for SSC exams!
Rule 1: All A are B
[Venn: Circle A completely inside Circle B]
Rule 2: No A is B
[Venn: Circles A and B separate, no overlap]
Rule 3: Some A are B
[Venn: Circles A and B overlapping]
Important Rules
- All + All = All ✓
- No + All = No ✓
- Some + All = Some ✓
- No + No = No conclusion ✗
- Some + Some = No conclusion ✗
Complementary Pairs
- All A are B ⟺ Some A are not B (Complementary)
- No A is B ⟺ Some A are B (Complementary)
Note: At least one from complementary pair always follows!