Which of the following statements is logically equivalent to the statement 'No professors are materialists'?

ASome non-materialists are not non-professors

BSome professors are non-materialists

CAll professors are non-materialists ✓ Correct

DAll non-materialists are non-professors

Correct answer: (C) All professors are non-materialists

Explanation

The equivalent is 'All professors are non-materialists'.

The given statement is an E proposition, no S are P.

Obversion changes the quality and complements the predicate.

'No professors are materialists' obverts to 'all professors are non-materialists'.

Obversion is a valid immediate inference that keeps the truth-value.

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