1. Criticism
Reductio ad Absurdum
Dilemmas
Counterexamples
Fallacies

2. Reductio ad Absurdum
aka. Modus Tollens
P → Q
Not Q
Therefore, Not P

3. Reductio ad Absurdum
If Determinism is true, then no actions are morally right or wrong.
Some actions are morally right or wrong.
Therefore, Determinism is not true.

4. Countering a Reductio
Bite the Bullet
Refute the Conditional

5. Dilemma Two Reductios together:
“Disjunctive Premise”: P -> (Q or R)
“Conjunctive Premise”: (Q->S) & (R->T)
Therefore, S or T
S and T are both absurd.
Therefore, not P.

6. Dilemma
If God exists, then either God allows evil or God is unable to prevent evil.
If God allows evil, then God is evil; and, if God is unable to prevent evil, then God is unworthy of worship.
God cannot be evil and God cannot be unworthy of worship.
Therefore, God does not exist.

7. Countering a Dilemma Going Between the Horns Grasping the Horn
Show a false dichotomy
Grasping the Horn
Refute one of the conditionals
Bite a Bullet
Accept one of the ‘absurd’ consequences

8. Counterexamples