UGC NET Questions (Paper – 1)

Contradictory propositions are such that one must be true and the other must be false in every possible situation. On the square of opposition, A and O types and E and I types stand in this relation. The defining feature is that they cannot both be true and cannot both be false. Therefore the pair described in the stem are called contradictories.

Option A:
Option A is correct because contradictories exactly capture the mutual exclusivity and exhaustive character mentioned. If one member of a contradictory pair holds, the other must fail, and vice versa. This condition matches the description given in the statement.

Option B:
Option B, contraries, cannot both be true but can both be false, as with "All S are P" and "No S are P". They lack the requirement that one must be true when the other is false. Hence contraries are not the right relation here.

Option C:
Option C, subcontraries, cannot both be false but can both be true, as in "Some S are P" and "Some S are not P". This is the opposite pattern to that described in the question. Therefore subcontraries are not appropriate.

Option D:
Option D, subalterns, involve a relation of implication between universal and particular forms where truth flows downward. They do not exhibit the stringent mutual exclusivity of contradictories. Thus subalterns do not fit the stem.