(A ⊃ B) ⊃ (∼B ⊃ ∼A)
Which of the following propositions is a proper assumption for conditional proof to prove that the above wff is a logical truth of PL?
A) (A ⊃ B) ⊃ (∼B ⊃ ∼A)
B) (A ⊃ B) ⊃ ∼B
C) A ⊃ B
D) A

Question

Quizplus · Accepted Answer

To prove the given well-formed formula (wff) as a logical truth using conditional proof, one typically assumes the antecedent of the main conditional statement and then shows that the consequent necessarily follows. In this case, the antecedent is "(A ⊃ B)", which is exactly what option C states. By assuming "A ⊃ B", one can then aim to derive "∼B ⊃ ∼A" through logical steps, thus proving the original statement.