Example Proof
The validity of this argument structure can be shown by using both conditional proof (CP) and reductio ad absurdum (RAA) in the following way:
| 1. | (CP assumption) | |
| 2. | (1: Simplification) | |
| 3. | (2: simplification) | |
| 4. | (2: simplification) | |
| 5. | (1: simplification) | |
| 6. | (RAA assumption) | |
| 7. | (6: DeMorgan's Law) | |
| 8. | (7: simplification) | |
| 9. | (7: simplification) | |
| 10. | (8: double negation) | |
| 11. | (9: double negation) | |
| 12. | (3,10: modus ponens) | |
| 13. | (4,11: modus ponens) | |
| 14. | (12: double negation) | |
| 15. | (5, 14: disjunctive syllogism) | |
| 16. | (13,15: conjunction) | |
| 17. | (6-16: RAA) | |
| 18. | (1-17: CP) |
Read more about this topic: Destructive Dilemma
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