Further to the recent news about Stephen Hawking’s views on the origin of the universe, Paul Davies has written a column for the Guardian’s ‘Comment is Free’ feature entitled ‘Stephen Hawking’s Big Bang Gaps’. In it, he makes some interesting points.
First, he points out that it was probably not only the universe, but also time itself, that began at the Big Bang:
Cosmologists are agreed that the universe began with a big bang 13.7 billion years ago. People naturally want to know what caused it. A simple answer is nothing: not because there was a mysterious state of nothing before the big bang, but because time itself began then – that is, there was no time “before” the big bang.
After warning us against ‘God-of-the’gaps’ approaches to science and apologetics (the origin of the universe being the biggest ‘gap’ that we like to take advantage of to prove the existence of God), he sets out Hawking’s view that the origin of the universe is not, after all, a gap for God to fill, as God is not necessary in order for the universe to come into existence:
The laws of physics can explain, (Hawking) says, how a universe of space, time and matter could emerge spontaneously, without the need for God. And most cosmologists agree: we don’t need a god-of-the-gaps to make the big bang go bang. It can happen as part of a natural process.
This however presents us with a further problem, as I mentioned in my earlier post on Hawking, and Davies seems to agree:
A much tougher problem now looms, however. What is the source of those ingenious laws that enable a universe to pop into being from nothing?
Indeed. And what do we mean by saying ‘It can happen as part of a natural process’, when the big bang is supposed to be the beginning of the process? How can the natural process cause anything before it has itself been initiated?
But this is where things get even more interesting (and – it must be added – speculative). Having told us that not only the universe, but also time itself, began with the big bang, Davies then goes on to talk about the possibility of the existence of a ‘multiverse’ – many universes, that is – the feeling being that if the laws of physics could produce one universe spontaneously, presumably they could do it with many more.
The favoured view now, and the one that Hawking shares, is that there were in fact many bangs, scattered through space and time, and many universes emerging therefrom, all perfectly naturally. The entire assemblage goes by the name of the multiverse.
Our universe is just one infinitesimal component amid this vast – probably infinite – multiverse, that itself had no origin in time. So according to this new cosmological theory, there was something before the big bang after all – a region of the multiverse pregnant with universe-sprouting potential.
This might have the added benefit (to an atheist, that is) of providing an alternative explanation for the fact that the laws of physics seem oh-so-carefully tuned to make possible the emergence of life as we know it. That might not be the case in the multiverse; each universe might have slightly different laws, and in the vast majority of them, our existence would not be possible.
An appealing feature of variegated bylaws is that they explain why our particular universe is uncannily bio-friendly; change our bylaws just a little bit and life would probably be impossible. The fact that we observe a universe “fine-tuned” for life is then no surprise: the more numerous bio-hostile universes are sterile and so go unseen.
But Davies is well aware that this theory does not, in fact, answer all the questions:
The multiverse comes with a lot of baggage, such as an overarching space and time to host all those bangs, a universe-generating mechanism to trigger them, physical fields to populate the universes with material stuff, and a selection of forces to make things happen. Cosmologists embrace these features by envisaging sweeping “meta-laws” that pervade the multiverse and spawn specific bylaws on a universe-by-universe basis. The meta-laws themselves remain unexplained – eternal, immutable transcendent entities that just happen to exist and must simply be accepted as given. In that respect the meta-laws have a similar status to an unexplained transcendent god.
I would agree with that assessment, with a further observation that the meta-laws share this further characteristic with God: there is no thoroughly conclusive proof of their existence. This, by the way, goes for a few other items in this discussion as well. As a commentator on another site put it:
What’s rather slipped by unnoticed with all this is that there’s absolutely no scientific evidence for M-theory, the anthropic principle or the multiverse…Compare and contrast with general relativity, which predicted the double-Newtonian deflection of light, and was vindicated within three years. String theory has been going for forty years now, and there’s still no evidence…
The “law” of gravity has got nothing to do with the early universe. Gravity occurs when there’s a variation in spatial energy density, usually caused by a concentration of energy tied up as matter. In the early universe there was no such inhomegeneity, and gravity didn’t stop the expansion of the universe. And what’s with this spontaneous creation? That’s just another non-answer. It reminds me of the old recipe for the spontaneous generation of mice. A piece of soiled cloth plus wheat and 21 days, and voila!
As I’ve said before on this blog, I’m certainly no scientist, but it seems to me that, despite the claims of Hawking, Dawkins, and others to have found perfectly satisfactory scientific answers to the question of existence, there are still a few outstanding items.