[Anonymous]

Affirming the consequent:
A -> B and B, therefore A

Denying the antecedent:
A -> B and -A, therefore -B

Shouldn’t affirming the consequent be called affirming the antecedent? The consequent is already affirmed, that’s a given.

Similarly, shouldn’t denying the antecedent be called denying the consequent? The antecedent is already denied. The fallacy was in denying the consequent.

[derosa8]

Seems like a good point to me Chris.

[gerard.casey]

Chris and John: I can see why you might think as you do. The names of these fallacies comes from what happens in the non-hypothetical premise, not from what happens in the conclusion!

You have the hypothetical premise, then you affirm the consequent (problem) and then you mistakenly conclude with the antecedent. Similarly, you have the hypothetical premise, you deny the antecedent (problem) and then mistakenly conclude with the negation of the consequent.

In the end, names are names but the important thing is to recognize the fallacy, whatever you want to call it.

[derosa8]

Thanks for the reply!

[gerard.casey]

JohnD: You’re welcome! Keep the posts coming. If something is odd, unusual or inexplicable to you, the chances are that it is so to others as well. You’re doing everybody a favour by posting.

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