Logic 2 PYQs (2025) (75 marks)

 

Logic – II (Subject Code: 66852)

Q.1) Answer the following in one or two sentences (Any Six)

a. Define mediate inference.
Ans: Mediate inference is a process of reasoning in which the conclusion is derived from two or more premises by means of a middle term connecting them.

b. State the meaning of "Anumana" with reference to Nyaya logic.
Ans: In Nyaya logic, "Anumana" means inference. It is the process of reasoning where a conclusion is drawn based on the observation of a universal relation between the middle term and the major term.

c. Illustrate the rule of Conjunction.
Ans: The rule of Conjunction states that if two propositions are true separately, then their conjunction is also true.
Symbolically: p, q ⊢ p ∧ q

d. Identify and illustrate the rule of deductive proof: “You practice martial art regularly. Therefore, either you practice martial art regularly or you play cricket on weekends.”
Ans: This is an example of the rule of Addition in deductive proof.
Symbolically: p ⊢ p ∨ q

e. Mention any two impediments of good reasoning.
Ans: (1) Prejudice or bias.
(2) Lack of proper attention or understanding.

f. Illustrate the fallacy of composition with an example.
Ans: The fallacy of composition occurs when what is true of the parts is assumed to be true of the whole.
Example: “Every player of the team is excellent, therefore the team must be excellent.”

g. What is Mill’s concept of positive condition with reference to causation?
Ans: According to J.S. Mill, the positive condition is the presence of circumstances that help produce the effect, forming part of the cause.

h. Define Pure hypothetical argument.
Ans: A pure hypothetical argument is one in which both premises and the conclusion are hypothetical propositions connected by logical implication.

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Q.2) Write Short Notes (Any Two)

a. Descriptive Hypothesis
Ans: A descriptive hypothesis is a statement that describes the characteristics of a variable or the relationship between variables. It provides an explanation of facts or phenomena based on observation.

b. Kinds of Dilemma
Ans: There are two kinds of dilemmas:
(1) Simple Dilemma – both alternatives lead to the same conclusion.
(2) Complex Dilemma – each alternative leads to a different conclusion.

c. Respondent Superior
Ans: Respondent Superior is a legal doctrine holding an employer or principal legally responsible for the wrongful acts of an employee or agent performed within the scope of employment.

d. Emotively Neutral Language
Ans: Emotively neutral language is free from emotional or biased expressions. It conveys meaning without influencing the listener’s emotions or attitudes.

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Q.3) Answer the following (Any Two)

a. Test the validity of the following categorical syllogism. State the figure and give reasons.
Every wealthy man is dishonest. No wealthy man is a philosopher. Therefore, no dishonest man is a philosopher.
Ans: This syllogism is invalid due to the fallacy of illicit minor. The middle term “wealthy man” is undistributed in the minor premise. Hence, the conclusion is not valid.

b. Some industrialists are philanthropists. Since all philanthropists are kind-hearted and many industrialists are kind-hearted.
Ans: The argument is invalid because the conclusion does not logically follow from the premises. The fallacy committed is “illicit process of the major term.”

c. Reduce indirectly: BAROCO
Ans: BAROCO (AOO–2) is indirectly reduced to CELARENT (EAE–1) by the method of Reductio ad Impossibile, showing its validity through contradiction.

d. Identify the non-formal fallacy, if any, and give reason.
“Modern surgery is a miracle of science; therefore, man has progressed.”
Ans: This commits the fallacy of composition — assuming that what is true for one part (surgery) applies to all (mankind).

“If we allow students having medical issues to appear for the additional examination, we must allow every absent student.”
Ans: This commits the fallacy of slippery slope — assuming that allowing one exception will lead to all exceptions.

“The 'X' diet product was endorsed by Amitabh Bachchan, so it will be beneficial.”
Ans: This commits the fallacy of argument ad verecundiam (appeal to authority).

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Q.4) Evaluate the following statements and identify the formal fallacy, if any.

(i) If Panchatantra contains fables, then it is interesting to read. If it is interesting to read, then it must be recommended. Therefore, if Panchatantra contains fables, then it must be recommended.
Ans: This is a valid argument based on the rule of Hypothetical Syllogism.

(ii) If fallacies are unavoidable, they would be excusable. Fallacies are not unavoidable. Therefore, fallacies would not be excusable.
Ans: This is an invalid argument — commits the fallacy of denying the antecedent.

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Q.4) Answer the following (Question No. 4(e) Compulsory, attempt any two from a, b, c, d)

a. Define Hypothesis. Describe the conditions of a good hypothesis.
Ans: A hypothesis is a tentative statement that explains the relationship between two or more variables.
Conditions of a good hypothesis: (1) It should be clear and specific. (2) It must be testable. (3) It should be consistent with known facts. (4) It should be simple and logical.

b. Illustrate and discuss the Third and Fourth figures of categorical syllogism.
Ans: Third Figure: The middle term occurs as the subject in both premises. Valid moods – DARAPTI, DATISI, DISAMIS, FELAPTON.
Fourth Figure: The middle term is predicate in the major and subject in the minor premise. Valid moods – BRAMANTIP, CAMENES, DIMARIS, FESAPO, FRESISON.

c. Analyse the concept of "Popular notion of cause."
Ans: The popular notion of cause refers to a common understanding of causation, where cause is considered as something that brings about an effect directly or indirectly, without deep scientific analysis.

d. Comment: “The difficult issue is not whether the end can ever justify the means, but which means is justified by which end.” (Peter Singer)
Ans: According to Peter Singer, ethical actions are judged by their consequences. He believes that the means can be justified only when they lead to morally good ends that promote overall happiness and reduce suffering.

e. Construct a complex constructive dilemma, rebut and refute it.
If a man is in politics, he is corrupt; and if he is disinterested in politics, he is an undesirable citizen.
Ans: Major Premise: If a man is in politics, he is corrupt; and if he is disinterested, he is undesirable.
Minor Premise: A man must be either in politics or disinterested.
Conclusion: Therefore, he is either corrupt or undesirable.
Rebuttal: Deny the conclusion by showing that some men in politics are honest and some disinterested citizens are good.
Refutation: Present a counterexample showing that both alternatives do not necessarily lead to undesirable results.