Final answer:
To prove the validity of the argument forms using the natural deduction method, we can use the rules of Modus Ponens, Modus Tollens, Disjunctive Syllogism, and Hypothetical Syllogism.
Step-by-step explanation:
To prove the validity of the argument forms using the natural deduction method, we can use the rules of Modus Ponens, Modus Tollens, Disjunctive Syllogism, and Hypothetical Syllogism.
a. Modus Ponens:
- If X is true, then Y is true.
- X is true.
- Therefore, Y is true.
b. Modus Tollens:
- If X is true, then Y is true.
- Y is not true.
- Therefore, X is not true.
c. Disjunctive Syllogism:
- X or Y is true.
- Not Y is true.
- Therefore, X is true.
d. Hypothetical Syllogism:
- If P is true, then Q is true.
- If Q is true, then R is true.
- Therefore, if P is true, then R is true.