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Tag: Best Tricks for Logical Reasoning UGC NET

  • UGC NET – Paper I – Unit 6: Logical Reasoning-MCQs

     (50 MCQs with Solutions)

    Section A – Nature of Reasoning & Arguments (Q 1–10)

    Q1. Which of the following is not a part of an argument?
    A) Premise B) Assumption C) Conclusion D) Question
    Answer: D
    Solution: An argument contains premises and conclusion; a question is not an assertion, hence not part of argument structure.

    Q2. Which of the following words generally introduces a conclusion?
    A) Since B) Because C) Therefore D) Given that
    Answer: C
    Solution: “Therefore,” “Thus,” and “Hence” signal conclusions.

    Q3. Statement: All cats are animals.
    The subject term is ____ and predicate term is ____.
    A) Cats – Animals B) Animals – Cats C) All – Cats D) None
    Answer: A

    Q4. “No politician is honest” is which type of categorical proposition?
    A) A B) E C) I D) O
    Answer: B
    Solution: Universal negative (E-type).

    Q5. A valid deductive argument:
    A) May have false premises but true conclusion.
    B) Cannot have true premises and false conclusion.
    C) May have true premises and false conclusion.
    D) Must be factually true.
    Answer: B
    Solution: Validity = if premises are true, conclusion must be true.

    Q6. “All poets are sensitive. Some sensitive people are foolish.”
    → Conclusion: Some poets are foolish.
    Valid or Invalid?
    Answer: Invalid.
    Solution: No direct overlap shown between poets and foolish; fallacy of undistributed middle.

    Q7. The reasoning “All metals expand on heating; iron is a metal; therefore iron expands” is:
    A) Deductive B) Inductive C) Abductive D) Analogy
    Answer: A

    Q8. In logic, truth refers to:
    A) Personal belief B) Empirical proof C) Agreement of statement with fact D) Social approval
    Answer: C

    Q9. “The road is wet, therefore it must have rained.” This is an example of:
    A) Deductive B) Inductive C) Abductive D) Fallacy
    Answer: C
    Solution: Inference to the best explanation (abduction).

    Q10. Inductive reasoning provides conclusions that are:
    A) Certain B) Probable C) Always false D) Deductive
    Answer: B

    Section B – Propositions & Square of Opposition (Q 11–20)

    Q11. “Some students are hardworking.” → Which proposition?
    A) A B) E C) I D) O
    Answer: C (Particular affirmative)

    Q12. Contradictory of “All S are P” is ____.
    A) Some S are P B) No S are P C) Some S are not P D) Some S are not non-P
    Answer: C

    Q13. From “No dogs are cats,” we may infer:
    A) All dogs are not cats B) Some dogs are cats C) Some dogs are not cats D) All cats are dogs
    Answer: C
    Solution: Universal negative (E) implies particular negative (O) under sub-alternation.

    Q14. “All A are B.” Which inference is valid?
    A) Some A are B B) Some B are A C) Some A are not B D) No B are A
    Answer: A

    Q15. Which pairs are contradictory?
    A) A & E B) A & O C) E & I D) B & O
    Answer: B

    Q16. Two propositions that cannot both be true but may both be false are:
    A) Contrary B) Contradictory C) Sub-contrary D) Equivalent
    Answer: A

    Q17. In the square of opposition, truth flows downward in:
    A) Contrary B) Sub-alternation C) Contradiction D) Sub-contrary
    Answer: B

    Q18. “Some trees are not green” → Type?
    A) O-proposition B) A C) I D) E
    Answer: A

    Q19. “All flowers are plants” and “No flowers are plants” are ____.
    A) Contrary B) Contradictory C) Sub-contrary D) Equivalent
    Answer: A

    Q20. “Some birds are not sparrows” contradicts ____.
    A) All birds are sparrows B) No birds are sparrows C) Some birds are sparrows D) All sparrows are birds
    Answer: A

    Section C – Syllogism & Venn Reasoning (Q 21–30)

    Q21. All mangoes are fruits. All fruits are edible. ∴ All mangoes are edible.
    Answer: Valid (syllogism, AAA figure 1 – Barbara)

    Q22. Some flowers are red. All red things are beautiful. ∴ Some flowers are beautiful.
    Answer: Valid (IAI – Darii)

    Q23. All students are learners. Some learners are teachers. ∴ Some students are teachers.
    Answer: Invalid (fallacy of undistributed middle)

    Q24. All A are B; No B are C ⇒ No A are C.
    Answer: Valid (EAE – Celarent)

    Q25. In a Venn diagram, if circles A and B overlap partly, it represents:
    A) All A are B B) Some A are B C) No A are B D) All B are A
    Answer: B

    Q26. “Some A are B and some B are C → Some A are C.”
    Answer: Invalid (‘Some–Some’ cannot yield a definite conclusion).

    Q27. For a valid syllogism, the middle term must be
    A) Distributed once at least B) Never distributed C) Always distributed twice D) None
    Answer: A

    Q28. The syllogism “No cats are dogs; All dogs are animals ⇒ No cats are animals” is
    A) Valid B) Invalid C) Partially true D) Inductive
    Answer: B

    Q29. All philosophers are thinkers; Some thinkers are teachers ⇒ ?
    Answer: Cannot be concluded (undistributed middle).

    Q30. In Venn analysis, “No A are B” → the circles are ____.
    A) One inside other B) Separate C) Overlapping D) Equal
    Answer: B

    Section D – Fallacies & Types of Reasoning (Q 31–38)

    Q31. “All doctors are educated; Mr. X is educated; ∴ Mr. X is doctor.” → Fallacy of ____.
    Answer: Undistributed middle.

    Q32. “He is wrong because he is young.”
    Answer: Ad Hominem fallacy (attacking person not argument).

    Q33. “Post hoc ergo propter hoc” means ____.
    Answer: False cause – assuming that after ⇒ therefore because of.

    Q34. “If the new phone is expensive, it must be good.” → Fallacy of ____.
    Answer: False cause / Hasty generalization.

    Q35. “Either you are with us or against us.” → Fallacy of ____.
    Answer: False dilemma.

    Q36. “He is a scientist, so whatever he says is true.” → Fallacy of ____.
    Answer: Appeal to authority.

    Q37. “Circular reasoning” occurs when ____.
    Answer: The conclusion repeats the premise in different words.

    Q38. Deductive reasoning ensures ____.
    Answer: Necessity of conclusion if premises are true.

    Section E – Indian Logic (Q 39–50)

    Q39. “Means of valid knowledge” in Indian logic is called ____.
    A) Hetu B) Pramāṇa C) Vyāpti D) Prameya
    Answer: B

    Q40. How many Pramāṇas are accepted in Nyāya school?
    A) 2 B) 3 C) 4 D) 5
    Answer: C (Pratyakṣa, Anumāna, Śabda, Upamāna)

    Q41. Match the following:

    1. Pratyakṣa → (a) Perception

    2. Anumāna → (b) Inference

    3. Upamāna → (c) Comparison
      Answer: 1-a, 2-b, 3-c

    Q42. The universal concomitance between reason and probandum is called ____.
    Answer: Vyāpti.

    Q43. In five-member syllogism, the first statement is called ____.
    Answer: Pratijñā (proposition).

    Q44. Correct sequence of Indian inference (Anumāna):
    1 Pratijñā, 2 Hetu, 3 Udāharaṇa, 4 Upanaya, 5 Nigamana.
    Answer: As listed.

    Q45. “Hill has fire because it has smoke.” → ‘Smoke’ is ____.
    Answer: Hetu (reason).

    Q46. Fallacy where reason is unproved (asiddha) means ____.
    Answer: Unestablished middle term – Hetu does not exist.

    Q47. “Fire is cold because it is a substance.” → Fallacy type ____.
    Answer: Viruddha (contradictory reason).

    Q48. “There is fire on hill because there is smoke and smoke is always with fire.” → Here ‘Smoke is always with fire’ shows ____.
    Answer: Vyāpti (universal relation).

    Q49. “Absence of sound means no vibration.” Knowledge by absence is called ____.
    Answer: Anupalabdhi.

    Q50. The fallacy where hetu is inconclusive (non-exclusive) is ____.
    Answer: Anaikāntika.

  • UGC NET Paper 1 – UNIT 6 — LOGICAL REASONING

    (For NTA UGC NET Paper I: Teaching & Research Aptitude)

    🎯 1. Purpose of this Unit

    Logical reasoning checks your ability to analyse arguments, evaluate evidence, and draw valid conclusions.
    In NET Paper 1, questions test:

    • The structure of reasoning (statements, premises, conclusions)

    • Valid vs invalid arguments

    • Categorical logic (propositions, syllogisms, square of opposition)

    • Inductive vs deductive logic

    • Venn-diagram validity tests

    • Indian logic (pramāṇas and hetvābhāsas)

    🧠 2. Understanding Arguments

    2.1 Structure of an Argument

    An argument is a group of statements where one (the conclusion) is claimed to follow from the others (the premises).

    Example
    Premise 1: All students are learners.
    Premise 2: Ravi is a student.
    ∴ Conclusion: Ravi is a learner.

    Term Meaning
    Premise Evidence / reason offered
    Conclusion Claim drawn from premises
    Indicator words Therefore, Hence, Thus → conclusion; Since, Because → premise

    ⚙️ 3. Argument Forms

    3.1 Deductive Reasoning

    • Moves from general to specific truth.

    • If premises true → conclusion must be true.

    • Validity matters, not factual truth.

    Form:
    All A are B. All B are C. ∴ All A are C.
    ✅ Valid Syllogism

    3.2 Inductive Reasoning

    • From particular to general.

    • Conclusion probable, not certain.
      Example: Observed 100 swans white ⇒ “All swans are white.”

    3.3 Abductive Reasoning

    • Inference to best explanation.
      Example: Wet road ⇒ Probably rained.

    🔢 4. Categorical Propositions

    A categorical proposition relates two categories (subject & predicate).

    Type Form Example Quantity Quality
    A All S are P All dogs are animals Universal Affirmative
    E No S are P No dogs are cats Universal Negative
    I Some S are P Some students are athletes Particular Affirmative
    O Some S are not P Some students are not athletes Particular Negative

    🧩 5. Classical Square of Opposition

    A (All S are P) ──contradictory── O (Some S are not P)
    │ \‾‾‾‾‾‾‾‾‾‾‾/ │
    │ contrary │
    │ │
    E (No S are P) ──contradictory── I (Some S are P)
    Relation Meaning
    Contradictory Opposite truth values (A ↔ O, E ↔ I)
    Contrary Both cannot be true (A & E)
    Sub-contrary Both cannot be false (I & O)
    Sub-alternation Truth flows downward (A → I; E → O)

    ⚖️ 6. Mood and Figure of Syllogism

    6.1 Mood

    Type sequence of propositions (A/E/I/O) for major, minor, conclusion.
    Example AAA (Barbara), EAE (Celarent).

    6.2 Figure

    Determined by position of the middle term (M).

    Figure Form Example
    1st M–P / S–M ⇒ S–P All men are mortal; Socrates is man ⇒ Socrates mortal.
    2nd P–M / S–M ⇒ S–P No reptile is warm-blooded; All snakes are reptiles ⇒ No snake is warm-blooded.

    🧮 7. Fallacies (Errors in Reasoning)

    7.1 Formal Fallacies (logical structure)

    • Affirming the consequent: p→q, q ⇒ p ❌

    • Denying the antecedent: p→q, ¬p ⇒ ¬q ❌

    7.2 Informal Fallacies (content errors)

    • Ad hominem: attacking person not argument.

    • Straw man: misrepresenting opponent’s claim.

    • False cause (post hoc): assuming A→B because A came first.

    • Circular reasoning: premise repeats conclusion.

    • Appeal to authority: treating authority as proof.

    💬 8. Language: Connotation and Denotation

    Term Meaning Example
    Denotation Literal dictionary meaning “Rose” = flower species
    Connotation Emotional or associated meaning “Rose” = love, beauty

    🔄 9. Analogies

    • Show relation similarity between two pairs.
      Example: Finger : Hand :: Toe : Foot
      Test → Find the same logical relationship (type, function, degree).

    🔷 10. Venn Diagrams & Testing Validity

    • Circles represent sets of objects.

    • Use to verify syllogistic arguments.

    Example:
    All A are B, All B are C ⇒ All A are C ✅
    Draw A inside B, B inside C.

    Common patterns:

    • Overlapping circles → “some”

    • Separate circles → “none”

    • Nested circles → “all”

    🪶 11. Indian Logic (Ānvīkṣikī Tradition)

    11.1 Pramāṇa — Means of Valid Knowledge

    1. Pratyakṣa (Perception): Direct sense experience.

    2. Anumāna (Inference): Reasoning from sign to proposition.

    3. Upamāna (Comparison): Knowledge through similarity.

    4. Śabda (Verbal Testimony): Trustworthy authority or scripture.

    5. Arthāpatti (Postulation / Implication): Presumption to explain facts.

    6. Anupalabdhi (Non-apprehension): Knowledge of absence.

    11.2 Structure of Anumāna (Inference)

    Traditional five steps (Nyāya syllogism):

    1. Pratijñā (Statement): Hill has fire.

    2. Hetu (Reason): Because it has smoke.

    3. Udāharaṇa (Example): Where there is smoke, there is fire (kitchen).

    4. Upanaya (Application): Like that, this hill has smoke.

    5. Nigamana (Conclusion): Therefore hill has fire.

    11.3 Vyāpti (Invariable Relation)

    • Universal relation between hetu (reason) and sādhya (conclusion).

    • Example: Smoke → Fire (always co-exist).

    11.4 Hetvābhāsas (Fallacies of Inference)

    Type Nature Example
    Asiddha Unproven reason Sky lotus fragrant (but no lotus exists).
    Viruddha Contradictory reason Fire is cold because it is fire.
    Satpratipakṣa Counter-reason Hill has no fire because there is water.
    Bādhita Opposed by perception Fire is cool (conflicts with experience).
    Anaikāntika Inconclusive / non-exclusive Crow visible ⇒ daytime (not always).

    🧭 12. Evaluating Deductive vs Inductive Reasoning

    Feature Deductive Inductive
    Direction General → Specific Specific → General
    Strength Certainty (if valid) Probability only
    Basis Logic of form Observation & pattern
    Example All humans mortal → Socrates mortal 100 crows seen black → All crows black

    🔍 13. Common Question Types in NET

    1. Identify valid/invalid argument.

    2. Determine type of proposition (A/E/I/O).

    3. Find contradictory statement.

    4. Use Venn diagram for syllogism.

    5. Spot logical fallacy.

    6. Apply Indian logic (pramāṇa, hetvābhāsa).

    7. Match deductive/inductive features.

    8. Solve analogy pattern reasoning.

    🧩 14. Shortcut Revision Map

    Concept Key Clue
    Argument = Premises + Conclusion Test validity via form
    A/E/I/O forms All/No/Some/Some not
    Square of Opposition A↔O contradictory
    Valid form p→q; p ⇒ q ✔️
    Fallacy Form invalid or premise irrelevant
    Venn diagram All = subset, Some = overlap, None = disjoint
    Indian Logic 6 Pramāṇas, 5 steps of Anumāna, 5 Hetvābhāsas

    🧠 15. Preparation Strategy

    Step Action
    1 Memorize A/E/I/O propositions & square.
    2 Practise truth-tables & syllogisms.
    3 Draw Venn diagrams for common patterns.
    4 Review Indian logic terms daily (Pratyakṣa → Anumāna → Hetvābhāsa).
    5 Attempt mock MCQs — mix concept + diagram + terminology.

    ✅ 16. Quick Summary

    • Argument = Premise → Conclusion.

    • Deductive = certainty; Inductive = probability.

    • Categorical logic: A, E, I, O + Square of Opposition.

    • Fallacies: Formal & Informal.

    • Language: Connotation/Denotation influence meaning.

    • Venn Diagrams: visual validity tests.

    • Indian Logic: 6 Pramāṇas, Anumāna structure, Hetvābhāsa types.