A Proof that Pr(H|E) > Pr(H) entails Pr(H|E) > Pr(H|~E)

A proof for the following conditional: Pr(H|E) > Pr(H) only if Pr(H|E) > Pr(H|~E).
  1. P(H|E) > P(H)
  2. P(H|E) > P(H) iff P(E|H) > P(E|~H) [Mackie's relevance criterion].
  3. P(E|H) > P(E|~H) [MP, 1 & 2].
  4. P(~E|H) = 1 - P(E|H) [subtraction].
  5. P(~E|~H) = 1 - P(E|~H) [subtraction].
  6. [1 - P(E|~H)] > [1 - P(E|H)] [from 3]. 
  7. P(~E|~H) > P(~E|H) [from 4, 5, & 6].
  8. P(H) > P(H|~E) iff P(~E|~H) > P(~E|H) [premise]. 
  9. P(H) > P(H|~E) [MP, 7 & 8].
  10. P(H|E) > P(H) > P(H|~E) [from (1), (9)].
  11. P(H|E) > P(H|~E) [from 10].
  12. Therefore, P(H|E) > P(H) only if P(H|E) > P(H|~E).

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