Given the argument: N ≡ D / D ⊃ ∼ N // ∼ N This argument is: A) Invalid; fails in 2^nd line. B) Invalid; fails in 4^th line. C) Valid. D) Invalid; fails in 5^th line. E) Invalid; fails in 3^rd line.

Question

Quizplus · Accepted Answer

The argument is valid because it uses a form of modus tollens. If N implies D (N ≡ D), and D implies not N (D ⊃ ∼N), then it logically follows that not N (∼N) must be true. This is a valid form of logical deduction.

Given the Argument: N ≡ D / D ⊃ ∼