According to a recent paper, published by Professor Andrei Linde and Dr Vitaly Vanchurin, both of the Department of Physics at Stanford University, there could be as many as 1010^10^7 universes in the cosmological – as distinct from quantum – Multiverse. See: http://arxiv.org/PS_cache/arxiv/pdf/0910/0910.1589v1.pdf.
Andrei Linde is the inventor of the model of cosmogenesis known as ‘cosmic inflation’, whereby, at the earliest instant of time t = (Għ/c3)½ = 1.616 × 10-35 s (the Planck time), the primitive Universe, which was initially super-dense, and ultra-hot, expanded in all directions at a velocity many times greater than the speed of light. This was possible solely because of the then enormous value of the cosmological constant, Λ.
The inflationary expansion continued until the Universe had cooled down sufficiently for the value of Λ to drop to where:
v ≤ c ≤ a(8πGρ/3 – kc2/a2 + Λc2/3)½ .
Here, the scale factor, a, which has the dimension, length, is taken to be numerically equal to 1. When Λ was equal to 10160, ignoring the contributions of ordinary and dark matter (which would have braked the expansion, in any event), and given hyperbolic space (k = –1), v = (1060c/1.732 – c) = 1.7309 × 1068 ms-1.
Clearly, there are very different régimes for high energy, high temperature, low energy, low temperature, physics. During the inflationary epoch, the ‘Big Bang’ (or ‘Big Whoosh’), there was one Universe, with one set of laws of physics, one set of initial conditions, and one, unified field of force, which united all four of the forces we know about today – gravity, electromagnetism, the weak and strong nuclear interactions.
However, after the cooling down, there was a breaking down, with the forces being split up into four, and the Universe becoming the Multiverse, being split up into myriads of separate universes (small ‘u’), of which our observable Universe is but one.
The other universes are too far away for us to see at present – they are beyond the particle horizon. However, as the Universe – our Universe – expands, the Big Bang recedes further and further into the past, becoming ever more distant from us in time and space. As it does so (and remember, from our POV, we are still at the centre of this great Sphere we call the Universe), more and more that was previously hidden becomes revealed to us – the Greek word for this process is apŏkalypsis, btw.
As they are beyond any possible communication range (with each other, not just with us) – ‘Einstein separated’, in the jargon – these separate universes can have different laws of physics. In some, the conditions will be perfectly suitable for life to arise, even conscious life, and so there will be observers. In others, the conditions will be altogether hostile for any kind of life at all, and so there will be none.
This takes care of the mystery of why our Universe is peculiarly advantageous for life, and for consciousness, at least to Professor Linde’s satisfaction. For the fact is that the laws of physics that apply here, and the values of the physical constants are remarkably well-attuned for life. If the value of the electromagnetic coupling constant, α, were the slightest bit different, for example, then organic chemistry, and thus our sort of life, the kind we know on Earth, including ourselves, would be completely impossible. For many other such instances, see Paul Davies’ book, The Accidental Universe, CUP, 1982.
Most scientists, like Linde and Vanchurin, invoke what is termed the ‘weak anthropic principle’ to account for this – namely that, the reason the Universe is so ordered is because, if it weren’t, we wouldn’t be here to observe it being that way. This is unanswerable, in a way, but also seems something of a cheating answer – a cheap debating point, rather than a genuine attempt to grapple with the mystery.
With lots of different universes available, life can play Russian roulette. In most of them, it takes the bullet, and never even gets started. In just a few, however, a very few – maybe only one in 10500, or less, it can get a foothold, because the conditions are right.
In fewer still, consciousness arises, and intelligent beings find themselves wondering why the Universe they are in is suitable for their kind of life, and ask if it is because it was created by a god, or God.
The problem with the Linde scenario is that, when you go back to the inflationary epoch, you go back to a period when there was just one Universe, and one set of physical laws, initial conditions, and only one physical force, as I said earlier.
So: where did they spring from? Let’s say that someone like the new Lucasian Professor of Mathematics at Cambridge, Professor Michael Green, who takes up his post on Sunday, 1st November (my 53rd Birthday!), see press release, University of Cambridge, a world-renowned pioneer and expert in Superstring Theory, comes up with the solution to how to unify quantum mechanics and the General Theory of Relativity, and how to put all four forces of nature, and the Higgs Field, and Professor Linde’s ‘inflaton field’ into one theory.
Even if you can manage to do that, you still haven’t accounted for where the mathematics came from in the first place. In pure mathematics, you get equations like this one (Euler’s identity):
eiπ + 1 = 0.
Here, e is Euler’s number, 2.7818281828459…, i is the square root of –1, and π is Archimedes’ constant, 3.1415926535897932384… (being an Aspie has its compensations – I have an eidetic, or ‘photographic’, memory, and can recall numbers like these from memory. The golden mean, f, is 1.6180339887498948482…).
This is true (and has been proved to be true), because of the meaning of the symbols employed – it is logically true. The same does not apply in the case of statements in physics. They are not a priori truths. They are, at best, hypotheses, which are falsifiable (not verifiable) a posteriori.
Consequently, no theory in physics, no matter how good it is, or no matter how many times it is supported by observation or experiment, should ever be regarded as proved, still less as though it were Holy Writ.
More importantly, though, no physical theory should be regarded as a substitute for Holy Writ, or as a spurious means of ‘refuting’ it. Professor Linde cannot tell me, or anyone else where the laws of physics came from, or who wrote them, or who set the initial conditions, or the parameters of the equations that governed the behaviour of the forces in the very early Universe. Nor can he account for the fact that, at the very beginning, there was literally nothing – i.e., no thing – no matter, no energy, no space and no time, and then there was something, the Universe, the instant of the Big Bang.
Professor Linde is like all too many of his colleagues – he wants Creatio ex nihilo without a Creator.
As for the quantum Multiverse, each separate universe would have to have its own quantum Multiverse, increasing the total number of universes to infinity. The quantum Multiverse arises from the Everett-de Witt Interpretation of quantum mechanics. It is a realist, determinist approach which does away with the idea of ‘collapse of the wave function’ (or ‘state vector reduction’).
Instead, all the possibilities represented by the various probability amplitude waves are realised, in different ‘parallel universes’, or histories. Schrödinger’s Cat is both dead and alive – dead in one universe and alive in another.
However, the laws of quantum mechanics – and thus of physics, generally – must be the same in all of these universes, so each separate cosmological universe, with its own physical laws, must have its own, entirely separate, quantum Multiverse, assuming that the quantum Multiverse idea is correct.