Why this topic matters · 8 min read
Syllogism is a high-frequency topic in SSC CGL Reasoning, appearing 2-4 questions per tier. You are given two or more statements and asked to find which conclusions logically follow. The key skill is ignoring real-world knowledge and applying pure logic. Questions range from simple two-statement syllogisms to tricky 'either-or' and 'complementary pair' conclusions. Getting this right is about learning a few rules cold and practicing quickly.
The Four Basic Statement Types
Every syllogism is built from four types of statements. Think of them as building blocks. Each statement has a Subject (S) and a Predicate (P). The type tells you how many of S are connected to P. You must identify the type before applying any rule.
- A-type (Universal Positive): All S are P. Example: All cats are animals.
- E-type (Universal Negative): No S is P. Example: No cat is a dog.
- I-type (Particular Positive): Some S are P. Example: Some cats are black.
- O-type (Particular Negative): Some S are not P. Example: Some cats are not black.
- Mnemonic: A E I O — like vowels in order. A and I are positive (Affirm), E and O are negative (dEny/sOme-not).
Distribution of Terms — The Core Rule Engine
A term is said to be distributed if the statement talks about ALL members of that term. This is the engine behind valid conclusions. You need to know which terms are distributed in which statement type.
- A-type: Subject is distributed, Predicate is NOT distributed.
- E-type: Both Subject and Predicate are distributed.
- I-type: Neither Subject nor Predicate is distributed.
- O-type: Only Predicate is distributed.
- Mnemonic: AEIO distribution — A distributes Subject only, E distributes Both, I distributes Neither, O distributes Object (Predicate) only. Remember: A-S, E-B, I-N, O-P.
Key formulas
Valid Conclusion Rules
1. Middle term must be distributed at least once. 2. No term can be distributed in conclusion if undistributed in premise. 3. Two negative premises give no conclusion. 4. Two particular premises give no conclusion. 5. If one premise is negative, conclusion must be negative. 6. If one premise is particular, conclusion must be particular.
When: Apply these six rules to check if any given conclusion is valid.
Worked examples
Premises: All dogs are animals (A). All animals are living (A). Conclusion: All dogs are living. Middle term = animals, distributed in 2nd premise (subject of A). Rule 1 satisfied. Both premises positive so conclusion can be positive. Both universal so conclusion can be universal. Result: Valid (All dogs are living follows).
Premises: Some cats are black (I). All black things are rare (A). Conclusion: Some cats are rare. Middle term = black, distributed in 2nd premise. One premise is particular (I), so conclusion must be particular. Conclusion is particular positive. Result: Valid.
The Venn Diagram Method — Faster for SSC
Most SSC CGL students find Venn diagrams faster than distribution rules during the exam. Draw circles for each category and shade or mark overlaps based on the statements. Then check if the conclusion must be true in ALL possible diagrams, not just one. If even one valid diagram breaks the conclusion, it does not follow.
- All A are B: Draw circle A completely inside circle B.
- No A is B: Draw circles A and B completely separate.
- Some A are B: Draw circles A and B overlapping partially.
- Some A are not B: Part of A is outside B — draw A partially outside B.
- A conclusion follows ONLY if it is true in every possible Venn diagram, not just one arrangement.
Either-Or (Complementary Pair) Conclusions
SSC CGL loves this trick. When neither conclusion I nor conclusion II individually follows, but together they cover all possibilities (one is I-type and the other is O-type for the same subject and predicate), then Either I or II follows. This is called a complementary pair.
- Complementary pair condition: One conclusion is Some A are B (I-type) and the other is Some A are not B (O-type) for the same A and B.
- Neither conclusion alone follows, but together they are exhaustive — so Either-Or follows.
- This does NOT apply to A-type and E-type pairs.
- Watch out: If one of the conclusions does follow on its own, do NOT choose Either-Or — choose that conclusion directly.
- Common SSC trap: Statements give no direct conclusion, but the I and O pair is present — answer is Either I or II follows.
Quick Combination Table for Two-Statement Syllogisms
In SSC CGL, most questions have two premises. This table tells you the type of conclusion you can draw based on the combination of premise types. Memorize it like a multiplication table.
- A + A = A conclusion (All + All = All)
- A + E = E conclusion (All + No = No)
- E + A = O-type reversed conclusion (No + All = Some not)
- A + I = I conclusion (All + Some = Some)
- I + A = I conclusion (Some + All = Some)
- E + I = O-type conclusion (No + Some = Some not)
- I + E = O-type reversed (Some + No = Some not reversed)
- All other combinations: No valid conclusion.
⚠ Common mistakes to avoid
- Using real-world knowledge: If the statement says All elephants are pens, you must accept it. Never reject a conclusion because it sounds absurd in real life.
- Forgetting the Either-Or rule: When both conclusions seem wrong, many aspirants mark Neither follows. Always check if they form a complementary I and O pair first.
- Concluding universally from particular premises: Two I-type premises never give any conclusion. Many students still write Some A are C — that is wrong.
- Reversing the middle term direction: The middle term must appear in BOTH premises. If the same term is not in both, you cannot connect the dots — no conclusion follows.
- Marking a conclusion valid from only one possible diagram: If there exists any valid Venn diagram where the conclusion breaks, the conclusion does NOT follow. Must hold in ALL cases.
🧠 Memory aids
- AEIO Vowels: A = All (universal positive), E = No (universal negative — think E for Exclude), I = Some (particular positive — I see some), O = Some-not (particular negative — Oh, not all).
- ASnEBINOP: A distributes Subject, E distributes Both, I distributes Neither, O distributes Predicate. Read as A-S, E-B, I-N, O-P.
- Six Golden Rules shortcut — Two Negatives = No Output, Two Particulars = No Output. Remember: 2N = 0, 2P = 0.
- Complementary Pair = I and O siblings of the same family (same subject and predicate). When neither stands alone, they stand together.
🎯 SSC CGL exam tips
- SSC CGL Tier 1 typically has 2-3 syllogism questions. They are usually straightforward two-statement problems with complementary pair traps added. Budget 45-60 seconds per question.
- Venn diagram method is recommended over formal rules for speed. Practice drawing the diagrams quickly — most questions are solvable in under a minute with good diagram practice.
- Recent SSC CGL papers (2022-2024) have increased the use of Either-Or conclusion questions. Always check for the I-O complementary pair before marking Neither follows.
- Be alert to questions with three statements — these appear occasionally in SSC CGL and require chaining conclusions step by step, treating the conclusion from the first two as a new premise.
- Negative conclusion trap: If one premise is negative (E or O type), the conclusion must be negative. If the question offers a positive conclusion in such cases, it is definitely wrong — eliminate it immediately to save time.
Q1 · medium · PYQ 2025
Read the following statement carefully and identify the conclusion that follows.
Statement: Some animals are carnivores. Some carnivores are wild.
Conclusions:
I. Some animals are wild.
II. All wild are animals.
- Only I follows
- Both I and II follow
- Neither I nor II follows
- Only II follows
Q2 · medium · AI-verified
Some books are novels. All novels are interesting. No interesting thing is boring. What follows definitely?
- No books are boring
- All books are interesting
- Some books are not boring
- Some novels are boring
Q3 · medium · PYQ 2024
Three statements are given, followed by three conclusions numbered I, II and III. Assuming the statements to be true, even if they seem to be at variance with commonly known facts, decide which of the conclusions logically follow(s) from the statements.
Statements: Some circles are rectangles. Some rectangles are squares. All squares are triangles.
Conclusions: I. No circle is a triangle. II. Some rectangles are triangles. III. All rectangles are triangles.
- Only conclusion III follows
- Both conclusion I and II follow
- Only conclusion I follows
- Only conclusion II follows
Q4 · medium · PYQ 2022
In the following question below are given some statements followed by some conclusions based on those statements. Taking the given statements to be true even if they seem to be at variance from commonly known facts. Read all the conclusions and then decide which of the given conclusion logically follows the given statements.
Statements:
I. All W are S.
II. No D is W.
Conclusion:
I. Some S are W.
II. All S are D.
III. No W is D.
- All conclusion follows.
- Only conclusion III follows.
- Both conclusions I and II follows.
- Both conclusions I and III follows.
Q5 · medium · AI-verified
Statements: All mangoes are fruits. Some fruits are sweet. All sweet things are tasty.
Conclusions: I. All mangoes are tasty. II. Some fruits are tasty. III. Some tasty things are fruits.
- Only II follows
- Only II and III follow
- Only I follows
- None follows