Comment author:CCC
02 December 2016 07:56:32AM
0 points
[-]

If I'm understanding correctly, I think you've made a mistake in your formal logic above—you equated "If B, then A" with "If A, then B" which is not at all the same.

No, he only inferred "If A, then B" from "If not B, then not A" which is a valid inference.

2) if not B, then not A. Which implies if A then B.

... but then he went on to say "How can an equivalent argument have explanatory power?" which seemed, to me, to assume that "if B then A" and "if A then B" are equivalent (which they are not).

## Comments (106)

BestNo, he only inferred "If A, then B" from "If not B, then not A" which is a valid inference.

*0 points [-]... but then he went on to say "How can an equivalent argument have explanatory power?" which seemed, to me, to assume that "if B then A" and "if A then B" are equivalent (which they are not).

I read that statement as implying that argument A is equivalent to argument B. (Not (1) and (2), which are statements

aboutarguments A and B)And, if A implies B

andB implies A, then it seems to me that A and B have to be equivalent to each other.