Because in any meaningful sense, there aren't various "possible worlds" each with its own God. There's one God, and His knowledge of and will toward the entire range of "possible worlds" (here meaning "worlds He could have made and perhaps did make") are unchanging.

Scott wrote:

Because in any meaningful sense, there aren't various "possible worlds" each with its own God. There's one God, and His knowledge of and will toward the entire range of "possible worlds" (here meaning "worlds He could have made and perhaps did make") are unchanging.

But just because there aren't possible worlds doesn't mean the concept doesn't have its uses. Divine simplicity entails that God is His act of will. But God wills to create this world. It would seem to follow then if God hadn't willed to create this world, He would have been different. And given God simply is His will, it would follow that if God didn't will to create He wouldn't even exist. But that seems ridiculous. So how do we simultaneously hold God is His act of will AND God could have willed otherwise?

(I have my speculations which I think work out, but I am interested in hearing the thoughts of others)

John West wrote:

Hi Tom,

First, I think we ought to introduce the old scholastic distinction between necessity-by-supposition and absolute necessity. For example, on the supposition that I have just eaten soup, it's necessary that I have just eaten soup. It's not, however, absolutely necessary that I have just eaten soup. It would not have been against my nature to choose to not eat soup. Similarly, on the supposition that God created the actual world, it's necessary that He created the actual world and not another world. It's not, however, absolutely necessary that He created the actual world, for it would not have been against His Nature to create a different world. 

My current view is that unactualized possible worlds can be treated as what Gregory Doolan calls pure possibles. Pure possibles are Exemplars that God doesn't actualize, but that would not have been outside of God's Power or against His Nature to actualize. Since this view gets possible worlds without requiring God create a different possible world, it seems to me that this alone deals with much of the problem.

But another useful distinction is Peter Geach's distinction between real properties and mere Cambridge properties. For instance, for Cicero to grow a beard is a real change in him. He acquires a real property. In contrast, if Cicero becomes shorter than Augustus because Augustus grows taller, this is not a real change in Cicero. It's what Peter Geach calls a mere “Cambridge change,” and therefore Cicero acquires a mere “Cambridge property”. The Doctrine of Divine Simplicity allows that God can have accidental “Cambridge properties”. 

Aquinas wrote that: “since therefore God is outside the whole order of creation, and all creatures are ordered to Him, and not conversely, it is manifest that creatures are really related to God Himself; whereas in God there is no real relation to creatures, but a relation only in idea, inasmuch as creatures are referred to Him” (ST I.13.7). This is the same as saying that the creatures' relation to God is a real one, but God's relation to creatures is a mere "Cambridge relation". So, I take it God would not really have been different had He actualized a different possible world. His creating any world is a mere Cambridge property. It would be a mere Cambridge difference[1].


[1]The argument comes from Edward Feser's reply to William Lane Craig's third criticism of Divine Simplicity, here.

The necessity by supposition and absolute necessity seems to be an irrelevant distinction in this context. It is what Stump and Kretzmann do to solve the problem (in their 1985 article in Faith and Philosophy, whose name I am blanking on), but they end up having to say the distinction between what God wills by necessity absolutely (His own nature) and what He wills by supposition (existing contingent things) is a mere logical distinction and not a real one. However, that seems problematic to me. 

Moreover, on simplicity, God is His act of will. But if God's act of will were necessary by supposition rather than by an absolute necessity, then God Himself would only be necessary by supposition which is strange.

Now, with regards to Cambridge properties, I think that is correct that God's being creator is a mere cambridge property. But that response needs to be fleshed out in my view. Here is why: If God is His will, then at least this prima facie seems that God is His will to create which would render creation just as necessary as God. 

TomD wrote:

John West wrote:

Hi Tom,

First, I think we ought to introduce the old scholastic distinction between necessity-by-supposition and absolute necessity. For example, on the supposition that I have just eaten soup, it's necessary that I have just eaten soup. It's not, however, absolutely necessary that I have just eaten soup. It would not have been against my nature to choose to not eat soup. Similarly, on the supposition that God created the actual world, it's necessary that He created the actual world and not another world. It's not, however, absolutely necessary that He created the actual world, for it would not have been against His Nature to create a different world. 

My current view is that unactualized possible worlds can be treated as what Gregory Doolan calls pure possibles. Pure possibles are Exemplars that God doesn't actualize, but that would not have been outside of God's Power or against His Nature to actualize. Since this view gets possible worlds without requiring God create a different possible world, it seems to me that this alone deals with much of the problem.

But another useful distinction is Peter Geach's distinction between real properties and mere Cambridge properties. For instance, for Cicero to grow a beard is a real change in him. He acquires a real property. In contrast, if Cicero becomes shorter than Augustus because Augustus grows taller, this is not a real change in Cicero. It's what Peter Geach calls a mere “Cambridge change,” and therefore Cicero acquires a mere “Cambridge property”. The Doctrine of Divine Simplicity allows that God can have accidental “Cambridge properties”. 

Aquinas wrote that: “since therefore God is outside the whole order of creation, and all creatures are ordered to Him, and not conversely, it is manifest that creatures are really related to God Himself; whereas in God there is no real relation to creatures, but a relation only in idea, inasmuch as creatures are referred to Him” (ST I.13.7). This is the same as saying that the creatures' relation to God is a real one, but God's relation to creatures is a mere "Cambridge relation". So, I take it God would not really have been different had He actualized a different possible world. His creating any world is a mere Cambridge property. It would be a mere Cambridge difference[1].


[1]The argument comes from Edward Feser's reply to William Lane Craig's third criticism of Divine Simplicity, here.

The necessity by supposition and absolute necessity seems to be an irrelevant distinction in this context.

How do you understand necessity? Necessity is defined as that without which something cannot be. There is no necessity in God, as God has no need of necessity.

Perhaps Tom's objection is something like this: God's knowledge of contingent truths seems to imply that God has contingent beliefs, since knowledge involves belief. But if God has contingent beliefs, then there is contingency in God, which conflicts with his simplicity - i.e. some parts of him are contingent, some parts aren't.)