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CHSE Odisha Elective Logic study materials
CHSE Odisha Elective Logic study resources

CHSE Odisha Elective Logic practice questions

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Question 1Introduction to Logic: Nature, Scope and Utility

Logic is best described as the study of which of the following?

  1. The psychological causes of belief
  2. The neurological basis of memory
  3. The forms and principles of valid inference Correct answer.
  4. The rhetorical techniques of persuasion

Explanation

Logic concerns the structure of reasoning: it examines when a conclusion follows necessarily from premises, abstracting from who is reasoning or why. Psychology and rhetoric study belief formation and persuasion, which are distinct from the validity of inference.

Question 2Introduction to Logic: Nature, Scope and Utility

The traditional division of logic into deductive and inductive reasoning rests on which distinction?

  1. Whether the argument is written or spoken
  2. Whether the reasoning is performed by experts or novices
  3. Whether the premises are true or false
  4. Whether the conclusion follows with necessity or with probability Correct answer.

Explanation

Deductive arguments aim at conclusions that must be true if the premises are true, while inductive arguments support conclusions that are only more or less probable. The truth of the premises themselves is a separate matter from the strength of the inferential link.

Question 3Introduction to Logic: Nature, Scope and Utility

In the standard analysis of an argument, the statement being supported is called the:

  1. Premise
  2. Conclusion Correct answer.
  3. Inference
  4. Assumption

Explanation

An argument consists of premises offered as evidence and a conclusion that they are meant to support. The inference is the step linking them, while an assumption is an unstated premise.

Question 4Introduction to Logic: Nature, Scope and Utility

Which feature most clearly distinguishes an argument from a mere explanation?

  1. An argument always contains more than two sentences
  2. An argument must be presented in formal symbols
  3. An argument offers reasons intended to establish that a claim is true Correct answer.
  4. An explanation always uses causal language

Explanation

An argument aims to justify a claim by giving evidence for its truth, whereas an explanation presupposes that something is the case and shows why. Length, causal vocabulary, and symbolic notation are incidental features that do not settle the matter.

Question 5Introduction to Logic: Nature, Scope and Utility

The utility of logic for clear writing is best illustrated by which practice?

  1. Replacing technical terms with vivid metaphors
  2. Shortening every paragraph to one sentence
  3. Adding rhetorical questions to engage the reader
  4. Checking that each stated conclusion is actually supported by the reasons given Correct answer.

Explanation

Logic trains writers to inspect the link between reasons and claims, exposing gaps where a conclusion outruns its evidence. Stylistic devices and brevity may aid readability but do not by themselves secure inferential support.

Question 6Introduction to Logic: Nature, Scope and Utility

A student says that since all observed swans in a region are white, the next swan seen there will be white. This reasoning is:

  1. Inductive and ampliative Correct answer.
  2. Deductive and valid
  3. Deductive but unsound
  4. Neither an argument nor an inference

Explanation

The conclusion goes beyond the observed cases, so the inference is ampliative and inductive: the premises make the conclusion probable rather than certain. A deductive argument would require a premise covering all swans, present and future.

Question 7Introduction to Logic: Nature, Scope and Utility

Which question falls within the scope of logic rather than of epistemology?

  1. How do people come to acquire their beliefs?
  2. Why do cultures differ in what they regard as sacred?
  3. What are the conditions for knowledge as justified true belief?
  4. Does the conclusion of this argument follow from its premises? Correct answer.

Explanation

Logic evaluates the relation of consequence between premises and conclusion, leaving questions about the origin, justification, and content of belief to other disciplines. Epistemology and anthropology address those broader concerns.

Question 8Introduction to Logic: Nature, Scope and Utility

The claim that logic is a normative rather than a merely descriptive discipline means that logic:

  1. Describes how people actually reason in laboratories
  2. Prescribes standards for correct inference Correct answer.
  3. Replaces mathematics in the curriculum
  4. Records the history of philosophical schools

Explanation

Logic sets standards specifying how one ought to reason if the goal is valid inference, in contrast to descriptive psychology, which reports how people in fact reason. This normative character is why logic can criticize actual reasoning as fallacious.

Question 9Introduction to Logic: Nature, Scope and Utility

A passage states that a metal expanded when heated because heating increases molecular motion. How should this passage be classified?

  1. An explanation of an accepted fact Correct answer.
  2. A definition of thermal expansion
  3. An inductive generalization from samples
  4. A deductive argument with a false premise

Explanation

The fact of expansion is taken for granted and the passage supplies the reason why it occurred, which is the mark of an explanation. No attempt is made to prove that the metal expanded.

Question 10Introduction to Logic: Nature, Scope and Utility

Which statement best captures the relationship between logic and language in the study of arguments?

  1. Arguments are conveyed in language, so clarity about terms and structure is a precondition of logical assessment Correct answer.
  2. Logic studies language sounds rather than meaning
  3. Language is irrelevant because logic deals only with mental images
  4. Logic requires that all arguments be translated into a foreign language

Explanation

Because premises and conclusions are expressed in sentences, ambiguity or vagueness in wording can hide the true logical form. Logic therefore begins by clarifying terms and identifying the inferential structure carried by language.

Question 11Introduction to Logic: Nature, Scope and Utility

Recognizing that an argument commits the fallacy of equivocation depends most directly on which logical skill?

  1. Counting the number of premises
  2. Identifying the author's nationality
  3. Detecting a shift in the meaning of a key term Correct answer.
  4. Measuring the length of the argument

Explanation

Equivocation arises when a term is used in different senses across the premises and conclusion, so the argument only appears to connect. Spotting that semantic shift is precisely what exposes the fallacy.

Question 12Introduction to Logic: Nature, Scope and Utility

Why is the study of logic often said to have practical value for citizenship?

  1. It guarantees that citizens will agree on political goals
  2. It equips people to evaluate public claims and detect defective reasoning Correct answer.
  3. It supplies authoritative answers to moral questions
  4. It removes the need for evidence in debate

Explanation

Logic provides tools for testing whether public arguments support their conclusions, which helps citizens resist manipulation and assess evidence. It does not settle substantive moral or political disputes by itself.

Question 13Introduction to Logic: Nature, Scope and Utility

An argument is valid but has a false premise. Which assessment is correct?

  1. The argument is invalid because a premise is false
  2. The argument cannot be evaluated logically
  3. The argument is sound because validity is preserved
  4. The argument is valid but not sound Correct answer.

Explanation

Validity concerns only whether the conclusion follows from the premises if they were true; soundness additionally requires that the premises actually be true. A valid argument with a false premise is therefore valid but unsound.

Question 14Introduction to Logic: Nature, Scope and Utility

Which consideration shows that formal logic cannot by itself settle every real dispute?

  1. Validity depends on form, but disputes often turn on the truth of premises and on empirical evidence Correct answer.
  2. Formal systems use symbols that printers cannot reproduce
  3. Formal logic was invented only in the twentieth century
  4. Logicians disagree about the rules of inference

Explanation

Formal logic tests whether conclusions follow from premises, but it does not by itself establish the truth of those premises, which may require empirical inquiry or value judgment. Hence logical competence is necessary but not sufficient for resolving disputes.

Question 15Introduction to Logic: Nature, Scope and Utility

A debater argues: 'Either the policy reduces cost or it reduces quality; it does not reduce cost; therefore it reduces quality.' Assessing this requires recognizing that the argument's form is:

  1. A definition of policy quality
  2. A disjunctive syllogism whose validity depends on the exclusivity of the alternatives Correct answer.
  3. An explanation of why the policy was adopted
  4. Inductive generalization from similar policies

Explanation

The inference has the shape of denying one disjunct to affirm the other, which is valid when the alternatives are genuinely exclusive. If both effects could occur together, the disjunction is inclusive and the conclusion no longer follows.

Question 16Introduction to Logic: Nature, Scope and Utility

Suppose someone claims that because logic studies correct reasoning, a person who reasons incorrectly is not really reasoning at all. What is the best logical reply?

  1. The claim confuses a normative standard with a description, since faulty reasoning is still reasoning that fails the standard Correct answer.
  2. The claim is right, since logic defines what reasoning is
  3. The claim is right, since only logicians can reason
  4. The claim is right, because incorrect reasoning has no structure

Explanation

Logic prescribes how reasoning ought to proceed, but the descriptive fact remains that people reason, sometimes badly. Treating failure to meet a norm as absence of the activity confuses the standard with the phenomenon it judges.

Question 17Terms, Propositions and Categorical Statements

In traditional logic, a term that can stand as the subject of a proposition and refers to a class of objects is called a:

  1. quantifier
  2. categorematic term Correct answer.
  3. copula
  4. syncategorematic term

Explanation

A categorematic term has independent meaning and can serve as subject or predicate, signifying a class. Words such as 'all' or 'not' lack such independent signification and are syncategorematic.

Question 18Terms, Propositions and Categorical Statements

Which pair of words is an example of contradictory (not contrary) terms?

  1. living and dead
  2. hot and cold
  3. just and unjust Correct answer.
  4. wise and foolish

Explanation

Contradictory terms exhaust the field with no middle: everything is either just or unjust. Contrary terms like hot and cold admit intermediate cases, so they do not exhaust the possibilities.

Question 19Terms, Propositions and Categorical Statements

A term used to refer to each member of a class taken separately, as 'student' in 'Every student passed', is said to be used:

  1. metaphorically
  2. collectively
  3. equivocally
  4. distributively Correct answer.

Explanation

Distributive use applies the term to each individual member of the class one by one. Collective use applies it to the group as a whole, as in 'The team won'.

Question 20Terms, Propositions and Categorical Statements

The proposition 'No politicians are honest' has which quantity and quality?

  1. universal affirmative
  2. particular affirmative
  3. universal negative Correct answer.
  4. particular negative

Explanation

'No' is a universal sign and 'are not' (implicit in 'No S are P') makes the proposition negative, giving the E form. Universal affirmative would require 'All', particular forms require 'some'.

Question 21Terms, Propositions and Categorical Statements

Which standard-form categorical proposition is the O proposition?

  1. Some S are not P Correct answer.
  2. All S are P
  3. Some S are P
  4. No S are P

Explanation

The four traditional forms are A (All S are P), E (No S are P), I (Some S are P) and O (Some S are not P). The O form is particular in quantity and negative in quality.

Question 22Terms, Propositions and Categorical Statements

In the proposition 'Some metals are not conductors', the term 'metals' is the:

  1. predicate term, undistributed
  2. subject term, distributed
  3. predicate term, distributed
  4. subject term, undistributed Correct answer.

Explanation

In an O proposition only the predicate is distributed; the subject is undistributed because the proposition speaks of some metals only. 'Metals' is the subject term and remains undistributed.

Question 23Terms, Propositions and Categorical Statements

Which term is distributed in a proposition of the A form?

  1. the predicate term only
  2. neither subject nor predicate
  3. the subject term only Correct answer.
  4. both subject and predicate

Explanation

In an A proposition the subject is distributed because the predicate is asserted of the whole class, but the predicate is undistributed because it is not asserted of its whole extension.

Question 24Terms, Propositions and Categorical Statements

'All that glitters is not gold' is best treated, when standardised, as which proposition?

  1. O: Some glittering things are not gold Correct answer.
  2. I: Some glittering things are gold
  3. A: All glittering things are gold
  4. E: No glittering things are gold

Explanation

The proverb is a denied universal, i.e. 'Not all that glitters is gold', which standardises to the O form 'Some glittering things are not gold'. Reading it as an E proposition would overstate the claim.

Question 25Terms, Propositions and Categorical Statements

Two propositions are contradictories when they:

  1. cannot both be true but can both be false
  2. cannot both be true and cannot both be false Correct answer.
  3. can both be true and can both be false
  4. have the same subject and predicate but differ only in quantity

Explanation

Contradictory propositions differ in both quantity and quality, so exactly one of the pair must be true. This is the relation holding between A and O, and between E and I.

Question 26Terms, Propositions and Categorical Statements

Given that 'All poets are dreamers' (A) is true, what follows about 'Some poets are not dreamers' (O)?

  1. It is true
  2. It is necessarily false only if the subject class is empty
  3. It is false Correct answer.
  4. It is undetermined

Explanation

A and O are contradictories, so if the A proposition is true the O proposition must be false. Exactly one member of a contradictory pair is true.

Question 27Terms, Propositions and Categorical Statements

If 'No reptiles are warm-blooded' (E) is true, which proposition is its subaltern?

  1. No warm-blooded creatures are reptiles
  2. All reptiles are warm-blooded
  3. Some reptiles are not warm-blooded Correct answer.
  4. Some reptiles are warm-blooded

Explanation

The subaltern of an E proposition is the O proposition with the same terms, namely 'Some reptiles are not warm-blooded'. Truth flows downward from universal to particular on the square.

Question 28Terms, Propositions and Categorical Statements

Which relation holds between 'All citizens are voters' and 'No citizens are voters'?

  1. contrariety Correct answer.
  2. subalternation
  3. subcontrariety
  4. contradiction

Explanation

These are the A and E forms with the same terms, which are contraries: they cannot both be true, though both may be false. Contradiction would require a difference in quality and quantity.

Question 29Terms, Propositions and Categorical Statements

Converting 'No mammals are birds' by conversion yields:

  1. No birds are mammals Correct answer.
  2. All mammals are non-birds
  3. All birds are non-mammals
  4. Some birds are not mammals

Explanation

An E proposition converts simply: swapping subject and predicate preserves truth because both terms are distributed. 'No birds are mammals' is the valid converse.

Question 30Terms, Propositions and Categorical Statements

Obversion of the A proposition 'All judges are fair' gives:

  1. Some judges are unfair
  2. No judges are unfair Correct answer.
  3. All fair persons are judges
  4. All judges are not fair

Explanation

Obversion keeps the subject and quality, changes quality, and replaces the predicate with its complement: 'No judges are unfair' (E). The original quality is affirmative, so the obverse is negative.

Question 31Terms, Propositions and Categorical Statements

'Some athletes are not professionals' converted by limitation (per accidens) is not valid because:

  1. the subject of an O proposition is distributed
  2. the predicate of an O proposition is undistributed
  3. conversion by limitation applies only to A propositions
  4. the O proposition cannot be converted at all Correct answer.

Explanation

An O proposition has an undistributed subject, so simple conversion would illicitly distribute it. Traditional logic therefore forbids converting O propositions in any form.

Question 32Terms, Propositions and Categorical Statements

Which pair of propositions is related by subalternation?

  1. 'Some roses are flowers' and 'Some roses are not flowers'
  2. 'All roses are flowers' and 'Some roses are flowers' Correct answer.
  3. 'All roses are flowers' and 'Some roses are not flowers'
  4. 'All roses are flowers' and 'No roses are flowers'

Explanation

Subalternation links a universal to the particular of the same quality: A to I, and E to O. 'All roses are flowers' and 'Some roses are flowers' are the A and I pair.

Question 33Terms, Propositions and Categorical Statements

A proposition whose subject term refers to an existing thing, so that it carries existential import, is said to be:

  1. disjunctive
  2. existential Correct answer.
  3. modal
  4. hypothetical

Explanation

An existential proposition asserts the existence of its subject, as in 'Some unicorns exist' or 'Socrates exists'. This matters because classical square relations assume existential import for universal propositions.

Question 34Terms, Propositions and Categorical Statements

'Either the train is late or the platform is wrong' is, in traditional classification, a:

  1. hypothetical proposition
  2. conjunctive proposition
  3. categorical proposition
  4. disjunctive proposition Correct answer.

Explanation

A disjunctive (alternative) proposition joins two categorical propositions by 'either...or'. The categorical proposition simply asserts or denies a predicate of a subject without such a connective.

Question 35Terms, Propositions and Categorical Statements

In 'All squares are rectangles', the predicate term 'rectangles' is undistributed because:

  1. the proposition is affirmative in quality
  2. the proposition says nothing about every rectangle Correct answer.
  3. rectangles form an empty class
  4. the subject term is distributed

Explanation

Distribution concerns whether a term is taken over its whole extension. The A proposition predicates 'rectangle' of squares without claiming anything about all rectangles, so the predicate is undistributed.

Question 36Terms, Propositions and Categorical Statements

Which proposition is the exact contradictory of 'Some books are not readable'?

  1. All books are readable Correct answer.
  2. All readable things are books
  3. Some books are readable
  4. No books are readable

Explanation

The contradictory of an O proposition is the A proposition with the same terms: 'All books are readable'. Contradictories differ in both quantity and quality.

Question 37Immediate Inference and the Square of Opposition

In the traditional square of opposition, which pair of propositions is related by the subalternation relation?

  1. A and E propositions
  2. A and O propositions
  3. I and O propositions
  4. A and I propositions Correct answer.

Explanation

Subalternation links a universal proposition to the particular proposition of the same quality: A stands above I, and E stands above O. The relation holds because truth flows downward from the universal to the particular. A and O, and I and O, are contradictory and subcontrary pairs respectively, not subalterns.

Question 38Immediate Inference and the Square of Opposition

Which pair of categorical propositions is governed by the contradictory relation?

  1. A and O Correct answer.
  2. A and E
  3. I and O
  4. E and I

Explanation

Contradictories differ in both quantity and quality, so they can never share a truth value: exactly one is true and the other false. A and O form one contradictory pair, and E and I form the other. The remaining pairs (A–E, I–O, A–I, E–O) are contraries, subcontraries, or subalterns.

Question 39Immediate Inference and the Square of Opposition

Two propositions are contraries when they cannot both be true but may both be false. Which square relation satisfies this description?

  1. A and E Correct answer.
  2. E and O
  3. I and O
  4. A and I

Explanation

Contraries are the two universal propositions A and E, which differ in quality while sharing universal quantity. They cannot both be true, yet both can be false when the subject class has some members outside the predicate. Particular pairs and universal-particular pairs follow different rules.

Question 40Immediate Inference and the Square of Opposition

The proposition 'No poets are realists' is given as false. What follows for its contradictory?

  1. 'Some poets are realists' is true. Correct answer.
  2. 'All poets are realists' is false.
  3. 'Some poets are not realists' is true.
  4. 'All poets are realists' is undetermined.

Explanation

'No poets are realists' is an E proposition, and its contradictory is the I proposition 'Some poets are realists'. Since contradictories always take opposite truth values, the falsity of E entails the truth of I. The A proposition is not the contradictory of E, so option 0 misapplies the relation.

Question 41Immediate Inference and the Square of Opposition

In the traditional square, what is the standard name for the relation between an A proposition and its corresponding I proposition?

  1. Subcontrariety
  2. Contradiction
  3. Contrariety
  4. Subalternation Correct answer.

Explanation

Subalternation is the vertical relation between a universal and the particular of the same quality, so A is the subalternant and I the subaltern. The rule is that truth descends and falsity ascends along this relation. Contradiction, contrariety, and subcontrariety describe the diagonal and horizontal relations instead.

Question 42Immediate Inference and the Square of Opposition

Which proposition is the subaltern of 'Some lawyers are not honest'?

  1. 'No lawyers are honest' Correct answer.
  2. 'All lawyers are not honest' is not a standard form
  3. 'Some lawyers are honest'
  4. 'All lawyers are honest'

Explanation

'Some lawyers are not honest' is an O proposition, and its subalternant is the E proposition of the same quality, namely 'No lawyers are honest'. The relation means the truth of E would guarantee the truth of O. The A and I forms belong to the opposite quality and are not subalterns of O.

Question 43Immediate Inference and the Square of Opposition

If 'Some metals are liquids' is true, what can be concluded about 'No metals are liquids'?

  1. It is undetermined.
  2. It is both true and false.
  3. It is false. Correct answer.
  4. It is true.

Explanation

'Some metals are liquids' is an I proposition and 'No metals are liquids' is the corresponding E proposition. I and E are contradictories, so they must have opposite truth values; a true I therefore makes E false. The contrary relation with A, not E, would leave the universal undetermined.

Question 44Immediate Inference and the Square of Opposition

Suppose 'All judges are impartial' is false. What follows about 'Some judges are impartial'?

  1. It is true.
  2. It is contradictory to the original.
  3. It is undetermined. Correct answer.
  4. It is false.

Explanation

A and I are subalterns, and the rule of subalternation lets falsity travel upward, not downward. From the falsity of the universal A nothing follows about the particular I, which may still be true. Only the truth of A would guarantee the truth of I.

Question 45Immediate Inference and the Square of Opposition

'Some students are not diligent' is false. What is the status of 'All students are diligent'?

  1. True Correct answer.
  2. False
  3. Undetermined
  4. Self-contradictory

Explanation

The false proposition is an O proposition, and its contradictory is the A proposition 'All students are diligent'. Because contradictories always differ in truth value, the falsity of O entails the truth of A. No other square relation gives so strong a result.

Question 46Immediate Inference and the Square of Opposition

Both 'All citizens are voters' and 'No citizens are voters' are asserted. According to the traditional square, what does this show?

  1. The two propositions are subcontraries.
  2. Both propositions may consistently be true.
  3. At least one of the two must be false, since contraries cannot both be true. Correct answer.
  4. The two propositions are contradictories.

Explanation

A and E are contraries, and the traditional square holds that contraries cannot both be true, though both may be false. Asserting both therefore guarantees that at least one is false. They are not contradictories, because contradictories cannot both be false either.

Question 47Immediate Inference and the Square of Opposition

'Some birds are penguins' and 'Some birds are not penguins' are both true. Which square relation does this illustrate?

  1. Contrariety
  2. Subcontrariety Correct answer.
  3. Contradiction
  4. Subalternation

Explanation

I and O are subcontraries, and the traditional rule allows both to be true simultaneously, though they cannot both be false. The example shows exactly this joint truth. Contraries and contradictories cannot both be true, and subalternation is a vertical relation between universals and particulars.

Question 48Immediate Inference and the Square of Opposition

If 'No machines are conscious' is true, which conclusion about 'Some machines are not conscious' is valid?

  1. It is undetermined.
  2. It is true. Correct answer.
  3. It is false.
  4. It is contrary to the premise.

Explanation

The premise is an E proposition and the conclusion is its subaltern O proposition. In subalternation, the truth of the universal guarantees the truth of the particular beneath it. Hence the O proposition must be true whenever E is true.

Question 49Immediate Inference and the Square of Opposition

A student claims that 'All roses are red' and 'Some roses are not red' can both be false. How should this claim be assessed?

  1. Incorrect, because these propositions are contradictories and exactly one is true. Correct answer.
  2. Correct, because subcontraries may both be false.
  3. Correct, because contraries may both be false.
  4. Incorrect, because both propositions must be true together.

Explanation

The two propositions differ in both quantity and quality, so they are contradictories and must take opposite truth values. That means one is true and the other false, never both false. The rule about both being false belongs to contraries, which the student has confused with contradictories.

Question 50Immediate Inference and the Square of Opposition

Which statement correctly describes the traditional doctrine of subcontraries?

  1. The truth of one guarantees the truth of the other.
  2. They must always have opposite truth values.
  3. They cannot both be true but may both be false.
  4. They cannot both be false but may both be true. Correct answer.

Explanation

Subcontraries are the two particular propositions I and O, which differ in quality. The traditional square holds that they cannot both be false, since the falsity of one entails the truth of the other, yet both may be true. This distinguishes them from contraries and contradictories.