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« on: November 13, 2005, 08:25:42 pm »
modus ponens
if P, then Q.
P.
Therefore, Q.
modus tollens
If P, then Q.
Q is false.
Therefore, P is false.
disjuctive syllogism
P or Q.
Not P.
Therefore, Q.
hypothetical syllogism
If I do not wake up, then I cannot go to school.
If I cannot go to school, then I will not attend class.
Therefore, if I do not wake up, then I will not attend class.
constructive dilemma
If Arnold wins the election, he will be Governor.
If Cruz wins the election, he will be Governor.
Either Arnold or Cruz wins the election.
Therefore, either Arnold or Cruz will be the president.
destructive dilemma
If turtle wins, he will be Champion.
If rabbit wins, he will be Champion.
Either turtle or rabbit is not Champion.
Therefore, either turtle or rabbit did not win.
Others:
resolution
absorption
composition
double negative elimination
distribution
De Morgan's Laws
commutation
association
tautology
conditional proof
reductio ad absurdum
see rules of inference at wikipedia.org