Type your formal proof. To do this, first, copy and paste the argument, set up the proof, then make inferences until you deduce the conclusion.

Phil 1001 intro to logic

Directions: Use the proof method (M₉) to construct a formal proof to demonstrate that the following argument is valid:

A ⊃ B, B ⊃ C, C ⊃ D /∴ A ⊃ ~ (~C v ~D)

In the space below, either (OPTION 1) type your completed proof or (OPTION 2) upload a photo or screenshot of your handwritten completed proof.

OPTION 1: Type your formal proof. To do this, first, copy and paste the argument, set up the proof, then make inferences until you deduce the conclusion. To the right of each inference, identify the line number(s) from which it was deduced and the abbreviation of the rule of natural deduction used to make the inference. You can copy and paste any of the following symbols as needed: ~ • v ⊃ ≡ ( ) [ ] → |