1. P ⊃ ~M 2. C ⊃ M 3. ~L v C 4. (~P ⊃ ~E) • (~E ⊃ ~C) 5. P v ~P /~L 6. ~P ⊃ ~E 4, simplification 7. ~~E ⊃ ~~P 6, transposition 8. E ⊃ P 7, double negation 9. E ⊃ ~M 8,1 hypothetical syllogism 10. ~E v ~M 9, material implication 11. ~(E • M) 10, deMorgan's law 12. ~C v M 2, material implication 13. (~E ⊃ ~C) • (~P ⊃ ~E) 4, commutation 14. ~E ⊃ ~C 13, simplification 15. ~~E v ~C 14, material implication 16. E v ~C 15, double negation 17. ~C v E 16, commutation 18. (~C v E) • (~C v M) 17,12, conjunction 19. ~C v (E • M) 18, distribution 20. (E • M) v ~C 19, commutation 21. ~C 20,11, disjunctive syllogism 22. C v ~L 3, commutation 23. ~L 22,21 disjunctive syllogism Edwin