Some Problems with the Multiverse
But the more you look at the idea of the multiverse, the less it seems to present an acceptable alternative to God. Believers in God have no difficulty in accepting that there is a large number of possible universes. They will exist in the mind of God, but they will not be actual physical universes. They will include, for example, universes in which there is intolerable suffering for all sentient beings for no reason at all. There will be universes in which I, or someone exactly like me, exists but does the exact opposite of everything I do in this universe. If I decide not to steal a large sum of money in this universe, I will decide to steal it in some other universe.
In Tegmark's (2007) view, there will be universes in which pink elephants endlessly dance gavottes and other universes in which unicorns and mermaids really do exist. There will be universes in which there is a creator God but other universes in which there is not and some universes in which there are many gods. Everything will be true somewhere. To most people, this idea seems a more extravagant proposal than any known religious creed. Indeed, every system of religious belief will be true in some universe. That does not have much to offer in the way of economy, simplicity, or plausibility.
What makes the range of possible universes what they are? Is there an exhaustive realm of all possibilities? What principle could ensure that all of these possibilities actually exist? If the set of possibilities is infinite, could all of them actually exist—can one have an actual infinite number of universes (that is, a number that is always larger than any number you can think of)? The problems multiply on reflection. It is not that the proposal is silly, but to say that it is simpler than proposing an intelligent Creator is not convincing.
But the extreme proposal that all possible universes exist is the only one that makes the existence of this universe virtually certain. If you go for the less extravagant "bubble universe" view or the "splitting universe" view, you only get a limited number of universes. What number of universes is needed to make the existence of this universe less improbable? If the set of possible universes is infinite, we might have to say that the existence of any universe at all is hugely improbable. But the existence of a large number of universes would not be less improbable; if anything, it would be more improbable. For, if the existence of one universe is highly improbable, then the existence of 1 + n universes is even more improbable, by a factor of n. So, a limited multiverse would not really help to make this universe more likely. It would only compound the problem of why the precise number of universes, having the nature they do, exists.
It could be said that universes are generated by chance from quantum laws. But now the problem is that of where and in what sense the laws of quantum physics exist. And how does a set of laws produce actual physical universes? As Stephen Hawking has said, "What is it that breathes fire into the equations and makes a universe for them to describe?" (1998, 190). How can you get physical things out of sets of mathematical equations? That would indeed be the modern equivalent of the Philosophers' Stone, which was supposed to turn lead into gold. But it would be much more powerful, for it would turn nothing into everything.
We are back to the final question: if there is something that is ultimately self-existent, that logically precedes the existence of everything else, what is it? The multiverse theory, in at least some forms, seems to place that ultimate in a Platonic realm of mathematical truths. But in what sense does such a Platonic realm exist?
At just this point, theism offers what seems to be a wholly rational hypothesis.
First, mathematical equations are conceived by minds, so this ultimate existent is suspiciously mind-like—more like God than like matter. If possible universes are considered as mathematical structures, they will be necessary, and it is reasonable to postulate that there must be an actual necessary mind in which they subsist.
Second, there is no reason that God may not create many universes, so the multiverse theory does not compete as an alternative to God. It just extends the creative power of God further than we had thought.
Third, most people would think that there needs to be a selection principle, by which some universe or universes are selected to be actual out of the realm of possible universes. The quasi-Platonic mathematical realm, which is a realm of pure necessity, cannot itself account for the existence of contingent universes. You need an additional, non-mathematical principle that can account for the existence of contingent universes. As I suggested in chapter one, a good explanatory selection principle is that a universe is chosen for the sake of realizing some otherwise unobtainable value or worthwhile set of states and processes. But that implies that the Ultimate Reality has something analogous to purpose or intention—again, that it is mind-like.
Fourth, it seems plausible to suppose that values only exist as values if there is something like a consciousness that places a value on them, that recognizes and appreciates their value. The selection principle will operate only if there is a consciousness that can appreciate the possibility of value.
Fifth, only a Being with active causal power can bring physical universes into being. That causal power must be different from, and not part of, any universe that it brings into being. It must be sufficient to produce all the amazing complexity of physical universes. This suggests a reality of enormous power, existing beyond any particular physical or material universe. Further than that it is hard to go, but a Being that conceives, intends, and brings matter into existence is remarkably like the classical idea of God as the cause of all finite existence through knowledge and intention.
Of course, this does not prove God. But if your choices are between the existence of a huge number of universes, all of which exist for no particular reason, and a Supreme Intelligence, existing by necessity, that selects contingent universes from the realm of all possibilities for the sake of their value, anyone may be forgiven for thinking that God is the simpler and more rational hypothesis.
The problem of the multiverse is a complex and exciting one, and it places the hypothesis of God firmly on the intellectual agenda. The God hypothesis seems to be at least as good as the available alternatives, though this consideration alone will not intellectually compel anyone to believe there is a God. The whole issue is discussed from many different viewpoints, theistic and naturalistic, by Bernard Carr (2007), and his book, Universe or Multiverse?, provides a masterly discussion of state-of-the-art thinking at the time of its publication.