(February 1, 2022 at 2:56 pm)The Grand Nudger Wrote: That argument that william lane craig uses/butchers is platingas modal ontological argument. Possible worlds analysis is a type of semantics used to explore propositional and first order modal logic. The quantifiers all, some, necessarily, and possibly are added to the usual and, or, not...and if-then.
Nothing to do with a multiverse.
@Mister Agenda
Platingas formulation makes it explicit.
Quote:A being has maximal excellence in a given possible world W if and only if it is omnipotent, omniscient and wholly good in W; and
A being has maximal greatness if it has maximal excellence in every possible world.
It is possible that there is a being that has maximal greatness. (Premise)
Therefore, possibly, it is necessarily true that an omniscient, omnipotent, and perfectly good being exists.
Therefore, (by axiom S5) it is necessarily true that an omniscient, omnipotent and perfectly good being exists.
Therefore, an omniscient, omnipotent and perfectly good being exists.
Platinga makes a basic mistake in modal logic when he assumes it is possible for a being with maximal greatness to exist. That is an assumption, not in a single world, but in ALL worlds.
What he *should* have assumed is that it is possible that a being of maximal excellence exists (which means it exists in at least one possible world). But that does not lead to a valid argument for the rest of his steps.
The trick is saying it is possible that a necessary being exists. That is a double quantification over possible worlds in a way that is invalid.
