Hartshorne's Modal Argument (for God)
What follows is one of the most challenging subjects you will ever hear about. It is the best way to get a head ache, but I think it proves the existence of God. The problem is it requires a very specialized background to understand it. First you have to understand modal logic. Modal Logic is so called because it turns upon the use of so called "modal operators." It's called "modal" because it is the logic of modes of being. "modes" as in what type of existence something exits in, whether it is dependent upon other things, whether it can cease or fail to exist and so forth. The modal operators are "necessity," "contingency" "impossibly," "possibility." Necessity and contingency lie at the base of our modern understanding of cause and effect. They come from scholastic notions of logic, but the distinction between the notion our modern notions of c/e and the scholastic ones in the middle ages is not that great.