SYLLOGISM — COMPLETE GUIDE FOR SSC CGL ─────────────────────────────────────
CORE CONCEPT ─────────────────────────────────────
Syllogism is a logic-based topic where you are given two or more statements and you must find which conclusions MUST be true based on those statements. You do NOT use your general knowledge. You only use what the statements tell you. Even if a conclusion seems true in real life, it is WRONG unless the statements prove it. ─────────────────────────────────────
KEY RULES / PROPERTIES ─────────────────────────────────────
There are 4 types of statements you will see: • Type A — Universal Positive: 'All A are B'
• Type E — Universal Negative: 'No A is B' • Type I — Particular Positive: 'Some A are B'
• Type O — Particular Negative: 'Some A are not B' Distribution Rule (very important):
A term is 'distributed' when the statement talks about ALL members of that group. — In 'All A are B': A is distributed, B is NOT
— In 'No A is B': Both A and B are distributed — In 'Some A are B': Neither A nor B is distributed
— In 'Some A are not B': Only B is distributed ─────────────────────────────────────
(The Golden Combination Rules)
─────────────────────────────────────
These are the standard valid conclusion patterns. Memorise them:
EXTRA RULE: If both statements are Particular (Some + Some), NO conclusion is possible.
─────────────────────────────────────
'Which conclusion follows?' — choose from 4 options 2
When neither conclusion alone follows but together they cover all possibilities, the answer is 'Either I or II follows' Either-Or Trick: Use this ONLY when both conclusions are complementary (one positive + one negative about the same subject and predicate) AND individually neither follows. ─────────────────────────────────────
For Either-Or to apply: Conclusion 1 + Conclusion 2 must be an I-O pair (Some A are C + Some A are not C) with the SAME subject and predicate. No other pair qualifies
For any two statements to give a conclusion, the MIDDLE TERM (the common term between both statements) must be distributed at least ONCE. If the middle term is NOT distributed in either statement, write NO CONCLUSION immediately. ─────────────────────────────────────
Identify the pattern — All + All = All
Apply formula → All cats are animals. ✓ (Conclusion I follows)
If All cats are animals, then reversing a universal positive gives 'Some animals are cats' (this is the converse of an A-type = I-type). ✓ (Conclusion II also follows) Answer: Both Conclusion I and II follow. ───────────────────────────────────── WORKED EXAMPLE 2 ───────────────────────────────────── Statements: 1. Some pens are books. 2. No book is a pencil. Conclusions: I. Some pens are not pencils. II. No pen is a pencil.
Pattern = Some + No = Some Not
Apply formula → Some pens are not pencils. ✓ (Conclusion I follows)
'No pen is a pencil' would need All+No pattern. We only have Some+No, so this is too strong. ✗ (Conclusion II does NOT follow) Answer: Only Conclusion I follows. ───────────────────────────────────── #1 MOST COMMON TRAP ───────────────────────────────────── Students assume that if 'All A are B' is given, then 'All B are A' must also be true. THIS IS WRONG. The correct reverse of 'All A are B' is only 'Some B are A'. Reversing an All statement to another All statement is the biggest mistake in syllogism and directly costs marks in SSC CGL every year.
46graded MCQs · easy to hard · full solution & trap analysis · showing 20 of 46
Difficulty-graded, bookmarkable, with timed mode. Free account — no credit card.