UGC NET PAPER 1 · CODE 00 · UNIT 06

UGC NET Paper 1 Unit 6: Logical Reasoning Notes and MCQs

Logical Reasoning rewards clear definitions more than hard calculation. If you can name the four proposition types, spot common fallacies and recall the pramanas of Indian logic, most questions become quick marks. These notes cover each syllabus topic briefly, so candidates from any subject can revise them in one sitting.

Arguments
Fallacies
Syllogism
Venn diagrams
Indian logic

7 syllabus topics
600+ free MCQs
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Updated 11 October 2026

NET Law 058 is an independent study aid, not affiliated with UGC or NTA. Always check the official UGC NET syllabus and the latest official sources for any data.

What Unit 6 covers

Logical Reasoning is short on content but heavy on precision, so learn definitions exactly and practise with small examples. The official syllabus lists 7 topics for this unit. Each is explained below with the points examiners most often use.

1Understanding the structure of arguments: argument forms, structure and fallacies

An argument is a set of statements in which the premises are offered as support for a conclusion. Indicator words such as therefore, hence and because help to find them.
A deductive argument is valid if the conclusion follows necessarily from the premises. A valid argument with all true premises is called sound.
A valid argument can have a false conclusion if a premise is false, and an invalid argument can have a true conclusion by accident. Validity is about form, truth is about content.
A fallacy is an error in reasoning that makes an argument look better than it is.

2Categorical propositions, mood and figure; formal and informal fallacies

Four standard forms: A (All S are P), E (No S are P), I (Some S are P) and O (Some S are not P). A and E are universal; I and O are particular.
A categorical syllogism has three terms (major, minor and middle) and three propositions. Mood is the pattern of A, E, I and O in it, and figure is the position of the middle term in the premises.
Formal fallacies break a rule of syllogism, for example the undistributed middle, or a term distributed in the conclusion but not in the premise. Two negative premises give no conclusion.
Informal fallacies depend on content or language, for example ad hominem, straw man, begging the question, false cause, hasty generalisation and equivocation.

3Uses of language, connotations and denotations; classical square of opposition

Language can be informative, expressive or directive. Questions of definition and meaning often turn on which use is intended.
Denotation (extension) is the set of things a term applies to. Connotation (intension) is the set of qualities that define the term.
Square of opposition: A and E are contraries, I and O are subcontraries, A and O (and E and I) are contradictories, and A to I and E to O are subalternation.
Contradictories always have opposite truth values. Contraries cannot both be true, and subcontraries cannot both be false.

4Evaluating and distinguishing deductive and inductive reasoning

Deductive reasoning goes from general premises to a particular conclusion, and the conclusion is certain if the argument is valid.
Inductive reasoning goes from particular cases to a general conclusion, and the conclusion is only probable. More evidence makes it stronger, but never certain.
Deductive arguments are judged as valid or invalid. Inductive arguments are judged as strong or weak.
Common inductive forms are generalisation, analogy, causal inference and statistical reasoning.

5Analogies

An analogical argument claims that two things alike in some respects are alike in another. Its strength depends on how many relevant similarities there are and how few relevant differences.
Verbal analogy questions ask you to find the same relationship in a second pair, for example tool and user, part and whole, cause and effect.
A weak or false analogy ignores a relevant difference between the two cases.
First name the relationship in the given pair in one sentence, then test each option against that sentence.

6Venn diagrams: simple and multiple uses for establishing validity

Each class is drawn as a circle. Shading means the region is empty, and a mark (X) means at least one member exists there.
A syllogism is drawn with three overlapping circles. Draw the premises only, then check whether the conclusion is already shown.
Draw the universal premise (A or E) first, then the particular premise (I or O).
Modern Boolean logic does not assume that a class has members, so a universal premise alone does not prove a particular conclusion.

7Indian logic: means of knowledge; pramanas; inference and structure of inference

Pramana means a valid means of knowledge. The main ones are Pratyaksha (perception), Anumana (inference), Upamana (comparison), Shabda (verbal testimony), with Arthapatti and Anupalabdhi accepted by some schools.
Nyaya accepts four pramanas: Pratyaksha, Anumana, Upamana and Shabda. Charvaka accepts only perception, and Buddhists and Vaisheshika accept perception and inference.
The five-membered Nyaya inference is Pratijna (proposition), Hetu (reason), Udaharana (example), Upanaya (application) and Nigamana (conclusion).
In the hill-fire example the hill is the paksha, fire is the sadhya, and smoke is the hetu. The stated rule of invariable concomitance is called vyapti.

Quick reference tables

Common informal fallacies
Fallacy	What it does
Ad hominem	Attacks the person instead of the argument
Straw man	Misrepresents an opponent's view and attacks that version
Begging the question	Assumes the conclusion in the premises (circular reasoning)
Argumentum ad ignorantiam	Claims something is true because it has not been proved false
Post hoc ergo propter hoc	Assumes that what follows an event was caused by it
Hasty generalisation	Draws a general rule from too few cases
Equivocation	Uses a word in two different senses in the same argument
Appeal to authority	Relies on an unqualified or irrelevant authority
Red herring	Introduces an irrelevant point to divert attention
Slippery slope	Claims one step will inevitably lead to a chain of bad results

Square of opposition and pramanas
Item	Meaning
A and E	Contraries: not both true, both can be false
I and O	Subcontraries: not both false, both can be true
A and O; E and I	Contradictories: exactly one is true
Pratyaksha	Perception
Anumana	Inference
Upamana	Comparison or analogy
Shabda	Verbal testimony of a reliable person or text

Key terms and facts to remember

Valid versus sound

Valid means the form is correct; sound means valid with all premises true.

A, E, I, O

All S are P; No S are P; Some S are P; Some S are not P.

Contradictories

A with O and E with I always have opposite truth values.

Three terms in a syllogism

Major, minor and middle terms; the middle term never appears in the conclusion.

Deduction

General to particular; conclusion is necessary if valid.

Induction

Particular to general; conclusion is only probable.

Pramanas in Nyaya

Pratyaksha, Anumana, Upamana and Shabda.

Five-membered inference

Pratijna, Hetu, Udaharana, Upanaya, Nigamana.

Vyapti

Invariable concomitance between hetu and sadhya, such as smoke and fire.

Charvaka

Accepts only perception as a pramana.

Venn diagram test

Draw the premises only; if the conclusion is already shown, the syllogism is valid.

Practise Logical Reasoning MCQs topic by topic

Beyond the six samples, all 628 questions for this unit are on their own pages, grouped by syllabus topic, with the answer key on the page.

See all 26 topic sets (628 MCQs) →

Try 6 sample questions

Tap “Show answer” after you have tried each one. These come from the 600+ MCQs in this unit.

1In the square of opposition, A and O propositions are:

Subcontraries
Subalterns
Contraries
Contradictories

Show answer and explanation

Answer: D. Contradictories

They always have opposite truth values.

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2'Post hoc ergo propter hoc' is the fallacy of:

Appeal to force
Attacking the person
Assuming that because B followed A, A caused B
Circular reasoning

Show answer and explanation

Answer: C. Assuming that because B followed A, A caused B

False cause fallacy.

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3'The hill has fire because it has smoke.' Smoke is the:

Paksha
Drishtanta
Hetu
Sadhya

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Answer: C. Hetu

Hetu is the reason or middle term.

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4Since 'No cats are dogs' is true, 'Some cats are dogs' is:

False
True
Undetermined
Neither

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Answer: A. False

E and I are contradictories.

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5Match: A Pratyaksha, B Anumana, C Shabda with (1) Inference (2) Perception (3) Testimony

A-2, B-1, C-3
A-1, B-2, C-3
A-2, B-3, C-1
A-3, B-1, C-2

Show answer and explanation

Answer: A. A-2, B-1, C-3

Pramanas in Nyaya.

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6Consider the statements: 1. A valid argument can have a false conclusion. 2. A sound argument has a false premise.

Only statement 1 is correct
Only statement 2 is correct
Both statements are correct
Neither statement is correct

Show answer and explanation

Answer: A. Only statement 1 is correct

Sound arguments have true premises.

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Practise all 600+ Unit 6 MCQs Take a free mock test

How to study this unit

Memorise the A, E, I, O forms and the square of opposition first. Many questions on contradiction, contrary and subcontrary use nothing else.
For fallacy questions, learn each fallacy with a one-line example. Match the example to the name instead of recalling definitions.
Practise drawing three-circle Venn diagrams on paper. Two or three syllogisms a day is enough to make the method automatic.

Planning your time? See the UGC NET Law preparation plans for 6 months, 3 months, 1 month or 2 weeks, or check the cut-off trend to set a target score.

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Last updated: 11 October 2026. Notes are a revision aid. Check official sources for the latest figures. Spotted a mistake? Write to netlawverse@gmail.com.