Which of the following statements are logically equivalent?

1.All saints are materialists.

2.No saints are non-materialists.

3.All non-materialists are non-saints.

4.No materialists are saints.

A2, 3 & 4 only

B1 & 3 only

C1 & 2 only

D1, 2 & 3 only ✓ Correct

Correct answer: (D) 1, 2 & 3 only

Explanation

Statements 1, 2 and 3 are mutually equivalent expressions of all saints are materialists.

Statement 2, no saints are non-materialists, is the obverse of Statement 1.

Statement 3, all non-materialists are non-saints, is the contrapositive of Statement 1.

Obversion and contraposition of an A proposition preserve its meaning intact.

Statement 4, no materialists are saints, is only the converse of the A form and does not follow.

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