UGC NET Questions (Paper – 1)

Contraries are propositions that cannot both be true at the same time but can both be false. On the square of opposition, the universal affirmative 'All S are P' and the universal negative 'No S are P' have this relation. There are circumstances where neither statement holds, making both false. Thus the relationship described in the stem is that of contraries.

Option A:
Option A, contradictories, are pairs of propositions that cannot both be true and cannot both be false; exactly one must be true. This relation holds between A and O or E and I, not between A and E. Therefore contradictories is not correct here.

Option B:
Option B, subcontraries, are propositions that cannot both be false but can both be true, a relation found between I and O propositions. Universal statements do not stand in this relation, so subcontraries cannot be the right answer.

Option C:
Option C, subalterns, refers to pairs where the truth of a universal implies the truth of its corresponding particular, such as A implying I. This is a different relation from the one asked about in the question.

Option D:
Option D is correct because contraries specifically describe the relation between universal affirmative and universal negative propositions on the square of opposition, matching the description in the stem.

Statements A, B, C, D and E correctly summarise the traditional and modern views of the square of opposition, while F is false. The traditional square treats A and E as contraries and I and O as subcontraries, and maintains that contradictory pairs cannot both be true or both be false. Modern logic largely drops contrariety and subcontrariety due to the rejection of existential import, but it keeps the contradictory relations intact. F is wrong because subalternation from universal to particular does not automatically hold under the modern, non-existential reading. Therefore A, B, C, D and E only is the correct combination.

Option A:
Option A is correct because it includes all the true statements and excludes only F, which misstates the scope of subalternation in modern logic. It captures both the traditional structure and the modifications introduced by the Boolean interpretation. This makes it the only option that fully matches accepted logical theory.

Option B:
Option B is incomplete because it omits E, which correctly notes that contradictory relations remain valid in both interpretations. Without E, the description of what survives in the modern view is incomplete. Hence A, B, C and D only does not represent the full set of correct statements.

Option C:
Option C is wrong because it includes F along with B, C, D and E. Including F treats subalternation as always valid in modern logic, which is not the case when universals are not assumed to have existential import. This error makes the combination inconsistent with standard textbook accounts.

Option D:
Option D is incorrect because it leaves out B and E and wrongly includes F. B is needed to characterise subcontraries, and E is needed to show what survives in the modern view. With these omissions and the inclusion of F, A, C, D and F only cannot be accepted as the correct set.

B is correct: A (“All S are P”) and O (“Some S are not P”) are contradictories. C is correct because contradictories cannot both be true and cannot both be false. E is correct: I and O are subcontraries (they cannot both be false but may both be true). A is false (it describes contraries, not contradictories). D is false because A and E are contraries, not subcontraries. Thus B, C and E only are correct.

Option A:
Option A is incomplete because it omits E, a key relation on the square involving particular propositions.

Option B:
Option B is wrong because it adds D, which misclassifies A and E as subcontraries.

Option C:
Option C is correct because it includes exactly the true relationships and excludes A and D, which are incorrect.

Option D:
Option D is incorrect because it includes A, which misdefines contradictories.