famous forms

Question 1

Constructive Dilemma

Answer 1

1. Either A or B
2. If A, then C
3. If B, then D
   So, 4. Either C or D

Question 2

Modus Ponens

Answer 2

1. If A then B
2. A
   So, 3. B

Question 3

Modus Tollens

Answer 3

1. If A, then B
2. Not B
   So, 3. Not A

Question 4

Hypothetical Syllogism

Answer 4

1. If A, then B
2. If B, then C
   So, 3. If A then C

Question 5

Disjunctive Syllogism

Answer 5

1. Either A or B
2. Not A
   So, 3. B

or opposite