One person’s modus ponens is another’s modus tollens.
I found a citation for this in Here is a hand to ‘Dretske, Fred (1995), Naturalizing the Mind, Cambridge, Mass.: The MIT Press. ISBN 0-262-04149-9’. Let’s give credit where credit is due; it’s a truth worth remembering about logically valid arguments.
I found a citation for this in Here is a hand to ‘Dretske, Fred (1995), Naturalizing the Mind, Cambridge, Mass.: The MIT Press. ISBN 0-262-04149-9’. Let’s give credit where credit is due; it’s a truth worth remembering about logically valid arguments.
It’s much older than that. A quick Google found a mention from 1973, but I would not be surprised to find it is at least a century older.