Syllogisms
Syllogisms ask you to judge which conclusions necessarily follow from two given statements, and CLAT rewards the candidate who can draw the Venn diagram in their head rather than guess from intuition.
10 questions · 5 minutes · instant scoring
What this topic actually tests
A syllogism gives two premises built from four statement types - the universal affirmative 'All A are B', the universal negative 'No A is B', the particular affirmative 'Some A are B', and the particular negative 'Some A are not B' - and asks whether given conclusions follow with certainty from those premises alone, ignoring real-world knowledge. The reliable method is the Venn diagram: draw a circle for each term and shade or mark the region the premise permits, then check whether every valid diagram consistent with both premises forces the conclusion to be true. A conclusion follows only if it holds in every possible diagram, not just the most natural one. The key technical idea is 'distribution' - a term is distributed if the statement refers to the entire class. 'All A are B' distributes A but not B; 'No A is B' distributes both; 'Some A are B' distributes neither; 'Some A are not B' distributes only B. A valid conclusion can never distribute a term that was undistributed in the premises, which is why chains like 'All A are B, Some B are C' cannot yield 'Some A are C' - the B mentioned in the second premise need not be the same B as in the first. Conversion rules also matter: 'All A are B' converts validly to 'Some B are A', and 'No A is B' converts to 'No B is A', but 'Some A are not B' cannot be converted at all. Worked example: from 'All engineers are graduates' and 'No graduate is unemployed', a Venn diagram places the engineer circle fully inside the graduate circle, and the graduate circle fully outside the unemployed circle; since engineers sit entirely inside graduates, and graduates never touch unemployed, engineers can never touch unemployed either, so 'No engineer is unemployed' follows with certainty.
The common trap on this topic
The most frequent CLAT mistake is assuming a particular statement automatically strengthens into a universal one further down a chain - for instance, treating 'All A are B' plus 'Some B are C' as proof that 'Some A are C', when the 'some' B that overlaps with C might be entirely outside the A-B overlap. Aspirants also wrongly convert 'All A are B' into 'All B are A', when only the weaker 'Some B are A' is guaranteed. A third trap appears in either-or conclusion pairs: candidates either apply the either-or rule too liberally, claiming it whenever two conclusions individually fail, or miss it entirely when the premises genuinely force one of two complementary particular and universal conclusions to be true. Finally, many students let real-world plausibility override the diagram - if a conclusion sounds sensible given general knowledge, they mark it as following even though the premises alone do not logically guarantee it, and conversely reject a conclusion that sounds odd even when the diagram proves it must be true. Syllogisms must be solved purely on the symbolic relationship between the classes as stated, never on outside knowledge of what is typically true in the real world.
Take the micro-test
Statements: All cats are dogs. All dogs are horses. Conclusions: I. All cats are horses. II. Some horses are cats.
Statements: No pens are pencils. All pencils are erasers. Conclusions: I. No erasers are pens. II. Some erasers are not pens.
Statements: All roses are flowers. Some flowers are red. Conclusions: I. Some roses are red. II. Some flowers are roses.
Statements: Some doctors are engineers. All engineers are wealthy. Conclusions: I. Some doctors are wealthy. II. Some wealthy people are doctors.
Statements: All squares are rectangles. No rectangle is a triangle. Conclusions: I. No square is a triangle. II. Some rectangles are squares.
Statements: Some teachers are writers. Some writers are painters. Conclusions: I. Some teachers are painters. II. No teachers are painters.
Statements: All mobiles are gadgets. Some gadgets are expensive. Conclusions: I. Some mobiles are expensive. II. All gadgets are mobiles.
Statements: No student is lazy. All lazy people are unsuccessful. Conclusions: I. Some unsuccessful people are not students. II. No student is unsuccessful.
Statements: All artists are creative. All creative people are dreamers. Some dreamers are poor. Conclusions: I. All artists are dreamers. II. Some artists are poor.
Statements: Some books are pens. All pens are costly. No costly item is cheap. Conclusions: I. Some books are costly. II. No books are cheap.
FAQ
Do syllogism conclusions have to match real-world facts?
No. Syllogisms are solved purely on the logical relationship between the given statements, even if a premise or conclusion seems factually odd, such as 'All cats are dogs'. You must judge only whether the conclusion necessarily follows from the stated premises.
When does the 'either-or' rule apply to two conclusions?
It applies only when neither conclusion follows individually, but the two conclusions form a genuine complementary pair (typically a particular affirmative and a universal negative about the same two terms) such that the premises make it impossible for both to be false at once.
Why doesn't 'All A are B' convert to 'All B are A'?
Because 'All A are B' only guarantees that the A circle sits inside the B circle; B may be larger and contain other elements besides A. Only the weaker statement 'Some B are A' is guaranteed by conversion.
Keep practising
- → Statement and Assumption
- → Strengthen and Weaken Arguments
- → Seating Arrangement
- → All Logical Reasoning practice
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