Final answer:
A sentence that is always false by virtue of its denotation is a contradiction, which combines a proposition with its negation and cannot be true under any circumstances.
Step-by-step explanation:
The question asks for the identification of a sentence that is always false by virtue of its denotation. Among the options given - Contradiction, Tautology, Paradox, and Ambiguity - the correct answer is Contradiction. A contradiction is a statement that combines a proposition and its negation, and as such, it cannot be true under any circumstances. For instance, saying 'My dog is on her bed and my dog is not on her bed' is a contradiction because it's impossible for both parts of the statement to be true at the same time, in the same sense. This is in alignment with the law of noncontradiction, which states that contradictory statements cannot both be true simultaneously.