Voodoo Logic

Denying the antecedent:


If P, then Q.
Not P.
Therefore, not Q


If there is TTX in the powder, there are zombies in Haiti.
There is not TTX in the powder.
Therefore, there are not zombies in Haiti.


Modus tollens:


If P, then Q.
Not Q.
Therefore, not P.


If there is TTX in the powder, there are zombies in Haiti.
There are not zombies in Haiti.
Therefore, there is no TTX in the powder.


Modus ponens:


If P, then Q.
P.
Therefore, Q.


If there is TTX in the powder, there are zombies in Haiti.
There is TTX in the powder.
Therefore, there are zombies in Haiti.


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