Our usual understanding of possible worlds are simply references to any possible state of affairs. They have no ontic grounding or actuality. It’s a semantic tool. However, there are those who treat possible worlds as actual. (The world actual becomes very fuzzy in modal realism). Philosopher David Lewis is the leading proponent of modal realism (Lewisian modal realism) and he has developed six essential doctrines to understanding modal realism:
- Possible worlds exist–they are just as real as our world
- Possible worlds are the same sort of things as our world–they differ in content, not in kind
- Possible worlds cannot be reduced to something more basic–they are irreducible entities in their own right
- Actuality is indexical. When we distinguish our world from other possible worlds by claiming that it alone is actual, we mean only that it is our world
- Possible worlds are unified by the spatiotemporal interrelations of their parts; every world is spatiotemporally isolated from every other world
- Possible worlds are causally isolated from each other
The first three doctrines entail that when we talk of our own world as being the only actual world, we cannot be asserting that our world has a special property not found in (or instantiated by) any other world – the property of actuality – but that we must be using the term `actual’ much as we use the term `here’ or `now’ — to indicate our position. This then yields the fourth doctrine. This is essential to Lewisian modal realism. The fifth doctrine concerns our principle of demarcation between worlds, and the sixth (although also offering some such principle) follows from the Lewisian analysis of causation.
(Source: please see Peter J. King’s “David Lewis: Modal Realism”)
May 1, 2012 at 10:59
Oh, I think possible worlds exist; so, I think they have an ontic grounding (the mind of God, perhaps). I think of them like properties, or states-of-affairs. They’re abstract objects, to be sure, but they exist. The question is whether or not all of these possible worlds are *actual*. I don’t think they’re all actual. But I don’t think every existing property, for example, is actualized either. So, no problem there. I think possible worlds (in that states-of-affairs sense) exist just the way numbers, sets, properties, and other abstract objects do, and I’m not sure why we should think otherwise.
I don’t know enough about the multi-verse, but doesn’t believing in such a thing commit you to a view very close to that of Lewis’s?
December 5, 2012 at 11:02
Sounds like Plantinga’s view, Roger.
Trackbacks
May 23, 2012 at 13:44