University:
Manchester University
Course:
INTD 343 | Philosophy of Mind
Academic year:

2019
Views:

129

Pages:

13
Author:

Clint W.

Deductive Argument #1 (1) If it’s raining, then you’ll need your umbrella. (2) It’s not raining. ∴ (3) You won’t need your umbrella. Deductive Argument #1 (1) If it’s raining, then you’ll need your umbrella. (2) It’s not raining. ∴ (3) You won’t need your umbrella. (1) If R, then U R = I’m a dog. (2) Not-R U = I’m a mammal. ∴ (3) Not-U [Denying the Antecedent] INVALID Deductive Argument #2 (1) If it’s raining, then you’ll need your umbrella. (2) It’s raining. ∴ (3) You’ll need your umbrella. Deductive Argument #2 (1) If it’s raining, then you’ll need your umbrella. (2) It’s raining. ∴ (3) You’ll need your umbrella. (1) If R, then U If P, then Q (2) R P ∴ (3) U ∴Q [Modus Ponens (Latin: “mode that affirms”)] VALID Deductive Argument #3 If Ed has black hair, then Ed is Italian. Ed does have black hair, so Ed is Italian. Deductive Argument #3 If Ed has black hair, then Ed is Italian. Ed does have black hair, so Ed is Italian. (1) If B, then I (2) B ∴ (3) I [Modus Ponens] VALID Ed Deductive Argument #4 If God exists, then there’s no evil in the world. But there is evil in the world, so God must not exist. Deductive Argument #4 If God exists, then there’s no evil in the world. But there is evil in the world, so God must not exist. (1) If G, then not-E If P, then Q (2) E not-Q ∴ (3) not-G ∴ not-P [Modus Tollens (Latin: “mode that denies”) VALID Deductive Argument #5 If the medicine doesn’t work, then the patient will die. The patient did in fact die, so I guess the medicine did not work. Deductive Argument #5 If the medicine doesn’t work, then the patient will die. The patient did in fact die, so I guess the medicine did not work. (1) If not-W, then D If P, then Q (2) D Q ∴ (3) not-W ∴P [Affirming the Consequent] INVALID Deductive Argument #6 That bicycle belongs to either John or Mary. But it looks too big for John. So it must belong to Mary. Deductive Argument #6 That bicycle belongs to either John or Mary. But it looks too big for John. So it must belong to Mary. (1) J or M (2) not-J ∴ (3) M [Disjunctive Syllogism] VALID P or Q not-P ∴Q