Which of the following propositions is the obverse of, and logically equivalent to, 'Some men are honest'?

ASome men are dishonest

BSome men are not dishonest ✓ Correct

CNo men are dishonest

DSome dishonest people are not men

Correct answer: (B) Some men are not dishonest

Explanation

The obverse of Some men are honest is Some men are not dishonest, which is equivalent to it.

Obversion changes the quality, turning the affirmative I into a negative O.

The predicate honest is replaced by its complement dishonest, that is not-honest.

So Some S are P becomes Some S are not non-P, preserving truth.

This makes Some men are not dishonest the equivalent obverse.

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