Negation as logical operation – UGC NET Question

Negation is the unary operation that takes a proposition and forms a new proposition that is true exactly when the original is false and false when the original is true. In symbolic logic, it is often represented by a tilde or a bar. Negation allows us to express denial or refusal within formal systems. Therefore the operation described is correctly called negation.

Option A:
Option A, implication, relates two propositions in a conditional structure "if p, then q" and does not simply reverse a truth value. It is a binary connective rather than a single-place operation. Thus implication does not fit the stem.

Option B:
Option B, equivalence, concerns a relation between two propositions that have the same truth value. It is not an operation that individually flips a truth value. Consequently equivalence is not appropriate here.

Option C:
Option C is correct because negation captures precisely the idea of truth-value reversal expressed in the question. The operation is fundamental in constructing logical opposites and in formulating contradictions.

Option D:
Option D, disjunction, joins two propositions with "or" and has truth conditions based on at least one disjunct being true. It does not operate on just one statement, so it cannot be the operation sought in the stem.