Comment by stirfish

I forgot what modus ponens/tollens are, but you get get it - I think I'm not generally intelligent

For people coming after me, or for anyone who took discrete math a decade ago and need a quick refresher:

Modus ponens (affirming): if P, then Q. P is true, therefore Q.

If it is raining, the grass is wet. It is raining. Therefore the grass is wet.

Modus tollens (denying): if P, then Q. Q is false. Therefore P is false.

If it is raining, then the grass is wet. The grass is not wet. Therefore, it is not raining.