Posted: Apr 24, 2011 1:07 am
by Paul Almond
Teuton wrote:
Allemann wrote:
If God was contingent, then he would depend on something outside of him, making him not the ultimate ground of being and therefore not God.


Even if God is absolutely ontologically independent in the sense that there is a possible world in which he is the only existent, he doesn't exist in all possible worlds.

"[I]t seems coherent to suppose that there exists a complex physical universe but no God, from which it follows that it is coherent to suppose that there exists no God, from which in turn it follows that God is not a logically necessary being."

(Swinburne, Richard. The Existence of God. 2nd ed. Oxford: Oxford University Press, 2004. p. 148)

It seems to me that the issue here is what we classify as "a possible world". For example, I could easily say this, paraphrasing Swinburne:

"It seems coherent to suppose that there exists a world in which the Goldbach conjecture is not true, from which it follows that it is coherent to suppose that the Goldbach conjecture is not true, from which in turn it follows that the Goldbach conjecture is not logically necessary."

and the problem of this, of course, is that we can't be sure, right now, whether the Goldbach conjecture is true or not - but if it is true it seems that it is necessarily true - something which we seem to have just ruled out merely by being able to conceive of the possibility that it is not true. I think Swinburne may actually be conflating everyday possibility with the more restrictive kind of possibility associated with a very restrictive set of possible worlds. Swinburne is imagining a set of possible worlds which all have to be consistent with each other - yet clearly, we don't know what form that set takes. It could be that all possible worlds have A, or it could be that all possible worlds have !A.

In fact, I'll go this far: I think Swinburne is doing, here, nothing less than a kind of inverted version of Plantinga's modal ontological argument.

Teuton wrote:
Paul Almond wrote:I've no problem with the idea that God, if he exists, is necessary - because that seems to be how many theists define him.


Yes, but there are different interpretations of the concept of necessary existence.


Yes, accepted. One thing I don't like about this subject is that some of the vocabulary can be hard to pin down.