Wednesday, January 23, 2008

Foreknowledge, Free Will, and Modal Logic

(Briarwood Mall, Ann Arbor)

I like the Internet Encyclopedia of Philosophy's article on "Forekowledge and Free Will."

A few quotes:

Ultimately the alleged incompatibility of foreknowledge and free will is shown to rest on a subtle logical error. When the error, a modal fallacy, is recognized, and remedied, the problem evaporates...

...Once the logical error is detected, and removed, the argument for epistemic determinism simply collapses. If some future action/choice is known prior to its occurrence, that event does not thereby become "necessary", "compelled", "forced", or what have you. Inasmuch as its description was, is, and will remain forever contingent, both it and its negation remain possible. Of course only one of the two was, is, and will remain true; while the other was, is, and will remain false. But truth and falsity, per se, do not determine a proposition's modality. Whether true or false, each of these propositions was, is, and will remain possible. Knowing – whether by God or a human being – some future event no more forces that event to occur than our learning that dinosaurs lived in (what is now) South Dakota forced those reptiles to take up residence there."