Which is the better explanation of cosmic fine tuning? A multiverse or a creator God?
Is the idea a multiverse a better explanation of cosmic fine tuning than the idea of a creator God? There is no evidence for a multiverse; the idea undermines scientific enquiry; it may not even be able to account for fine tuning; it may just push the problem up a level, and it is a very extravagant idea. For all these reasons, it is a poor explanation.
Quotations that are not attributed are taken from the ‘God: new evidence’ videos, © 2010 Focus Radio.
Most people who think seriously about cosmic fine-tuning agree that there are only two possible explanations: either the universe is the product of a purposeful Creator (who has made it the way it is so that complex life is possible) or there are many universes – perhaps even an infinite number, with different tunings. Given a wide enough range of universes, we feel intuitively that at least one of them will be fine-tuned for life. So we have a choice between God and a multiverse. Why, then, should we choose the ‘God’ option? What’s wrong with a multiverse?
1. A multiverse would not disprove God
Before we start exploring what’s wrong with a multiverse, we notice that if scientists could confirm that there were multiple universes, this would not disprove the existence of a creator God. What it would do (or might do) is to take away one argument for God’s reality – the argument from fine-tuning. It would still leave open the question of whether there is a God.
This is why a scientist and theologian like David Wilkinson can be relaxed about the possibility of a multiverse:
‘I don’t worry about a God who creates many universes. The God who creates this universe with a hundred billion stars in each of a hundred billion galaxies is big enough for me to try to struggle with as a concept. A few more billion galaxies wouldn’t be too worrying to me. It’s just a few noughts at the end of what is already a very long number.’
2. There is no evidence for a multiverse
The biggest single objection to the idea of multiple universes is that there is (at least, so far) no evidence for it. Richard Dawkins says that
‘Scientific belief is based on publicly checkable evidence.’
But he also advances multiple universes as an explanation for cosmic fine tuning, without any supporting evidence. This is self-contradictory.
As Rodney Holder says:
‘Curiously enough someone like Richard Dawkins says ‘no, I believe in a multiverse. That will explain [the fine tuning].’ On the other hand, Richard Dawkins tells you that you should only believe things on the basis of evidence. Well, there’s a massive contradiction there within the thought of Richard Dawkins.’
(Of course, in Dawkins’ own mind, there may not be a contradiction: given that cosmic fine-tuning is a reality, given that there are only two possible explanations, and given that he rules out the ‘God’ explanation in principle, a multiverse is the only option that is left. However, this does seem to put the cart before the horse.)
It is difficult to see how there even could be evidence for a multiverse – at least direct evidence. By definition, if there are other universes, they are what physicists call ‘causally separated’ from us. No information can pass from one universe to another. Without the passage of information, can there ever be direct evidence for other universes? It appears not.
It is often stated that there are theories of cosmology which either require, or suggest, the possibility of multiple universes. For example, in ‘A Designer Universe,’ Stephen Weinberg says:
According to the 'chaotic inflation' theories of André Linde and others, the expanding cloud of billions of galaxies that we call the big bang may be just one fragment of a much larger universe in which big bangs go off all the time, each one with different values for the fundamental constants. In any such picture, in which the universe contains many parts with different values for what we call the constants of nature, there would be no difficulty in understanding why these constants take values favorable to intelligent life. There would be a vast number of big bangs in which the constants of nature take values unfavorable for life, and many fewer where life is possible.
However, these theories are themselves speculative. There is no definite evidence for them. So to appeal to these theories in support of a multiverse is to use one kind of speculation to confirm another kind of speculation.
3. A multiverse undermines scientific enquiry
The idea of a multiverse undermines all scientific enquiry: for example, imagine you see some highly improbable event (all the molecules of air in the room suddenly arrange themselves in one corner, leaving a vacuum everywhere else). Well, so what? We live in a multiverse. Even the most unlikely of events are bound to happen somewhere. The problem is that you can use a multiverse to explain away absolutely anything. This has the potential to put a stop to scientific enquiry.
4. Even a multiverse may not be able to account for fine tuning
We instinctively feel that if there are enough universes, anything is possible. This is a good example of our instincts letting us down:
Even if scientists did discover conclusive evidence for a multiverse, this would not necessarily be enough to account for the fine-tuning. As John Polkinghorne says:
Simply by having a large or indeed an infinite array of universes you couldn’t be sure that you’d get one that was right for life. I mean, for example, there are an infinite number of even numbers, but never in that collection will you find a number with the property of oddness. So it’s not clear that having an infinite collection means you’ve got everything you might want.
So an infinite number of universes may not be enough to solve the fine-tuning problem.
5. A multiverse may just push the problem up a level
If the existence of a multiverse could somehow be proved, this may just push the problem of fine-tuning up a level: we would still need to ask why the laws that govern the multiverse produce such a massive range of diversity as to guarantee that complicated life like ours is possible in at least one universe?
6. The Multiverse is a very extravagant idea
A key scientific principle is ‘Occam’s Razor’ (named after William of Occam, 1285-1349). This says that ‘Plurality ought never to be posited without necessity.’ That is, scientific explanations should be as simple as they can be: you don’t make your explanation any more complicated than it needs to be to cover the ground.
The multiverse certainly seems to contradict this principle. It ‘posits plurality’ on a spectacular scale, multiplying universes without number. As John Polkinghorne says:
The multiverse option is a very extravagant suggestion. It postulates the existence of all these trillions and trillions of universes, all unobservable by us, all different in their characters and so very different that, by chance, one of them turns out to be OK for carbon based life. Now that’s a very bold speculation and it’s certainly not a scientific theory. It’s a metaphysical guess as we might say. It goes beyond physics into some sort of philosophy. As, of course, does the idea that the universe is a creation in the same sort of way. But I think that the multiverse is first of all a very uneconomic assumption to make.
(Some people may want to argue that the idea of multiple universes does not contradict Occam’s razor, because it is only multiplying the same kind of thing. (As a parallel example, we believe that the universe is made up of an imaginably huge number of atoms – but no-one thinks that this is multiplying entities unnecessarily: atoms are just one kind of thing.)
Even if we were to admit this, the most that anyone could claim is that both the idea of multiple universes and the ‘God’ explanation introduce at least one extra level of existence or explanation beyond the observable physical universe. This would mean that the two explanations were equivalent in terms of Occam’s Razor.)
An unwelcome idea
The idea that there could be a creator God is very unwelcome to some scientists. So, for example, Martin Rees, in his discussion of fine tuning in ‘Just Six Numbers,’ mentions the possibility, but then ignores it completely. Steven Weinberg and Richard Dawkins would be other examples of leading scientists for whom the idea of multiple universes offers an alternative to belief in God.
Yet, as John Polkinghorne points out, the multiverse only explains one thing:
It explains, or it explains away, the fine tuning of our universe by saying we’re just the winning ticket in the cosmic lottery. But I believe seeing the universe as a divine creation does lots of pieces of explanatory work. It not only explains the fine tuning, it explains why the universe is rationally beautiful, with wonderful laws of nature. It explains our widely attested human experience of an encounter with the sacred reality of God and so on. So there’s a cumulative case for seeing the universe as a creation, which doesn’t seem to me to have a counterpart on the multiverse side of the argument.
It is widely agreed that cosmic fine-tuning points to either multiple universes or a creator God. If you rule out the possibility of a creator, then you have little option other than to believe in multiple universes. However, if you keep an open mind, the lack of evidence for multiple universes should at least suggest that the ‘God’ option is worth investigating.
David Couchman MA, M.Sc, M.Min, March 2010
 Daily Telegraph Science Extra, Sept 11th 1989