Paul Davies, PhD, English physicist & professor, 1946-
“Before we leave the problem of contingency, something should be said about the so-called many-universes theory. According to this idea, currently popular with some physicists, there is not just one physical universe, but an infinity of them. All these universes somehow coexist ‘in parallel,’ each differing from the others, perhaps only slightly. It is conceivable that things could be arranged such that every sort of universe that is possible exists in this infinite set. If you want a universe, say, with an inverse-cube rather than inverse-square law of gravity, well, you will find one there somewhere. Most of these universes will not be inhabited, because the physical conditions therein will not be suitable for the formation of living organisms. Only those universes in which life can form and flourish to the point that conscious individuals arise will be observed. The rest go unseen. Any given observer will observe only a particular universe, and will not be directly aware of the others. That particular universe will be strongly contingent. Nevertheless, the question ‘Why this universe?’ is no longer relevant, because all possible universes exist. The set of all universes taken together is not contingent.”
— Paul Davies, The Mind of God, Touchstone, 1992 p190
“Before leaving the problem of the origin of the universe, I should say something about a recent cosmological theory in which the question of origin enters in a radically different way. In my book God and the New Physics I floated the idea that what we call the universe might have started out as an outgrowth of some larger system, which then detached itself to become an independent entity... Here space is represented as a two-dimensional sheet. In accordance with the general theory of relativity, we can imagine this sheet as curved. In particular, one can conceive of a localized bump forming on the sheet, and rising into a protuberance connected to the main sheet by a thin throat. It may then happen that the throat becomes progressively narrower, until it pinches off completely. The protuberance has then turned into a completely disconnected ‘bubble.’ The ‘mother’ sheet has given rise to a ‘child.’
“Amazingly, there is good reason to expect something like this to be going on in the real universe. The random fluctuations associated with quantum physics imply that, on an ultramicroscopic scale, all manner of bumps, wormholes, and bridges should be forming and collapsing throughout space-time. The Soviet physicist Andrei Linde has the idea that our universe started out this way, as a little bubble of space-time, which then ‘inflated’ at a fantastic rate to produce a big bang. Others have developed similar models. The ‘mother’ universe which spawned ours is also continuously inflating at a fantastic rate, and spewing out baby universes for all it is worth. If this state of affairs is correct, it implies that ‘our’ universe is only part of an infinite assemblage of universes, although it is self-contained now. The assemblage as a whole has no beginning or end. There are problems in any case in using words like ‘beginning’ and ‘end,’ because there is no suprauniversal time in which this spawning process takes place, although each bubble has its own internal time.”
— Paul Davies, The Mind of God, Touchstone, 1992 p70
“...Bother mother-and-child and the Hartle-Hawking theories adroitly circumvent the problems associated with a cosmic origin by appealing to quantum processes. The lesson to be learned is that quantum physics opens the door to universe of a finite age, the existence of which does not demand a well-defined prior cause. No special act of creation is needed.”
— Paul Davies, The Mind of God, Touchstone, 1992 p72
“In chapter 2 I argued that, given the laws of physics, the universe can create itself. Or, stated more correctly, the existence of a universe without an external first cause need no longer be regarded as conflicting with the laws of physics. This conclusion is based, in particular, on the application to cosmology of quantum physics. Given the laws, the existence of the universe is not itself miraculous. This makes it seem as if the laws of physics act as the ‘ground of being’ of the universe. Certainly, as far as most scientists are concerned, the bedrock of reality can be traced back to these laws. They are the eternal truths upon which the universe is built.”
— Paul Davies, The Mind of God, Touchstone, 1992 p73
“Undoubtedly the most serious challenge to the design argument comes from the alternative hypothesis of many universes, or multiple realities... The basic idea is that the universe we see is but one among a vast ensemble. When deployed as an attack on the design argument, the theory proposes that all possible physical conditions are represented somewhere among the ensemble, and that the reason why our own particular universe looks designed is that only in those universes which have that seemingly contrived form will life (and hence consciousness) be able to arise. Hence it is no surprise that we find ourselves in a universe so propitiously suited to biological requirements. It has been ‘anthropically selected.’
“First we must as what evidence there is for these other worlds. The philosopher George Gale has compiled a list of several physical theories that in one way or another imply an ensemble of universes. The most frequently discussed theory of multiple universes concerns an interpretation of quantum mechanics. To see how quantum uncertainty leads to the possibility of more than one world, consider a simple example. Imagine a single electron immersed in a magnetic field. The electron possesses an intrinsic spin which endows it with a ‘magnetic moment.’...
“...Mathematically, this arrangement is described by representing the electron by a state that is a ‘superposition’ of the two possibilities. That is to say, the state is – again, roughly speaking – a hybrid of two overlapping realities: spin-up and spin-down. If, now, a measurement is made of the energy, the result will always be found as either up or down, and not some weird mixture of the two. But the inherent uncertainty of quantum mechanics forbids your knowing in advance which of these two possibilities will actually prevail. The rules of quantum mechanics will, however, allow you to assign relative probabilities to the alternatives. In the example considered there is equal probability for up or down. Then, according to a crude version of the many-universes theory, when a measurement is made, the universe splits into two copies, one in which the spin is up, the other in which it is down.
“A more refined version envisages that there are always two universes involved, but that prior to the experiment they are identical in all respects. The effect of the experiment is to bring about their differentiation in respect of the electron’s spin direction. In the case that the probabilities are unequal one can imagine that there are many identical worlds in proportion to the relative probability. For example, if the probabilities were 2/3 up and 1/3 down, one could imagine three initially identical universes, two of which remain identical and have spin-up, the other differentiating itself by having spin-down. In general, one would need an infinite number of universes to cover all possibilities.
“Now imagine extending this idea from a single electron to every quantum particle in the universe. Throughout the cosmos, the inherent uncertainties that confront each and every quantum particle are continually being resolved by differentiation of reality into ever more independently existing universes. This image implies that everything that can happen, will happen. That is, every set of circumstances that is physically possible (though not everything that is logically possible) will be manifested somewhere among this infinite set of universes.
“The various universes must be considered to be in some sense ‘parallel’ or coexisting realities. Any given observer will, of course, see only one of them, but we must suppose that the conscious states of the observer will be part of the differentiation process, so that each of the many alternative worlds will carry copies of the minds of the observers. It is part of the theory that you can’t detect this mental ‘splitting’; each copy of us feels unique and integral. Nevertheless, there are stupendously many copies of ourselves in existence! Bizarre though the theory may seem, it is supported, in one version or another, by a large number of physicists as well as some philosophers. Its virtues are particularly compelling to those engaged in quantum cosmology, where alternative interpretations of quantum mechanics seem even less satisfactory.”
— Paul Davies, The Mind of God, Touchstone, 1992 p215-217
“Recently an interesting adaptation of the many-universes theory has been proposed by Lee Smolin which avoids some of the objections to the other many-universes schemes by providing a curious linkage between the needs of living organisms and the multiplicity of the many universes. In chapter 2 I explained how the investigations of quantum cosmology suggest that ‘baby universes’ can arise spontaneously as a result of quantum fluctuations, and that one may envisage a ‘mother universe’ giving rise to progeny in this way. One circumstance under which new universes might be born is the formation of a black hole...
“Smolin’s refinement of this speculation is that the extreme conditions of near-singularity would have the effect of causing small random variations in the laws of physics. In particular, the values of some of the constants of nature, such as particle masses, charges, and so on, might be slightly different in the daughter universe from what they were in its mother. The daughter universe might then evolve slightly differently. Given enough generations, quite wide variations would occur among the many universes. It is likely, however, that those which differ substantially from our own would not evolve stars like ours (recall that the conditions for the formation of stars are rather special). Because black holes are most likely to form from dead stars, such universes would not produce many black holes, and hence would not give birth to many baby universes. By contrast, those universes with physical parameters well suited to form many stars would also form many black holes and thence many baby universes possessing similar values of these parameters. This difference in cosmic fecundity acts as a type of Darwinian selection effect. Although the universes don’t actually compete, there are ‘successful’ and ‘less successful’ universes, so that the proportion of ’successful’ universes – in this case, efficient star-makers – in the total population will be rather large. Smolin then goes on to point out that the existence of stars is also an essential prerequisite for the formation of life. So the same conditions that encourage life also encourage the birth of other life-giving universes. In the Smolin scheme, life is not an extreme rarity, as it is in other many-universes theories. Instead, the large majority of universes are habitable.”
— Paul Davies, The Mind of God, Touchstone, 1992 p221-222
Richard Dawkins, PhD, British evolutionary biologist, 1941-
“...Different physicists espouse different kinds of anthropic solutions to the riddle of our existence.
“Hard-nosed physicists say that the six knobs [of physical constants necessary for life] were never free to vary in the first place. When we finally reach the long-hoped for Theory of Everything, we shall see that the six key numbers depend upon each other, or on something else as yet unknown, in ways that we today cannot imagine. The six numbers may turn out to be no freer to vary than is the ratio of a circle’s circumference to its diameter. It will turn out that there is only one way for a universe to be. Far from God being needed to twiddle six knobs, there are no knobs to twiddle.
“Other physicists (Martin Rees himself would be an example) find this unsatisfying, and I think I agree with them. It is indeed perfectly plausible that there is only one way for a universe to be. But why did that one way have to be such a set-up for our eventual evolution? Why did it have to be the kind of universe which seems almost as if, in the words of the theoretical physicist Freeman Dyson, it ‘must have known we were coming’?...
“This objection can be answered by the suggestion, which Martin Rees himself supports, that there are many universes, co-existing like bubbles of foam, in a ‘multiverse’ (or ‘megaverse,’ as Leonard Susskind prefers to call it). The laws and constants of any one universe, such as our observable universe, are by-laws. The multiverse as a whole has a plethora of alternative sets of by-laws. The anthropic principle kicks in to explain that we have to be in one of those universes (presumably a minority) whose by-laws happened to be propitious to our eventual evolution and hence contemplation of the problem...
“Another theoretical physicist, Lee Smolin, has developed a tantalizingly Darwinian variant on the multiverse theory, including both serial and parallel elements. Smolin’s idea, expounded in The Life of the Cosmos, hinges on the theory that daughter universes are born of parent universes, not in a fully fledged big crunch but more locally in black holes. Smolin adds a form of heredity: the fundamental constants of a daughter universe are slightly ‘mutated’ versions of the constants of its parent. Heredity is the essential ingredient of Darwinian natural selection, and the rest of Smolin’s theory follows naturally. Those universes that have what it takes to ‘survive’ and ‘reproduce’ come to predominate in the multiverse. ‘What it takes’ includes lasting long enough to ‘reproduce.’ Because the act of reproduction takes place in black holes, successful universes must have what it takes to make black holes. This ability entails various other properties. For example, the tendency for matter to condense into clouds and then stars is a prerequisite to making black holes. Stars also, as we have seen, are the precursors to the development of interesting chemistry, and hence life. So, Smolin suggests, there has been a Darwinian natural selection of universes in the multiverse, directly favouring the evolution of black hole fecundity and indirectly favouring the production of life...”
— Richard Dawkins, The God Delusion, Mariner Books, 2008 p172-175
“It is tempting to think (and many have succumbed) that to postulate a plethora of universes is a profligate luxury which should not be allowed. If we are going to permit the extravagance of a multiverse, so the argument runs we might as well be hung for a sheep as a lamb and allow a God. Aren’t they both equally uparsimonirous ad hoc hypotheses, and equally unsatisfactory? People who think that have not had their consciousness raised by natural selection. The key difference between the genuinely extravagant God hypothesis and the apparently extravagant multiverse hypothesis is one of statistical improbability. The multiverse, for all that it is extravagant, is simple. God, or any intelligent, decision-taking, calculating agent, would have to be highly improbably in the very same statistical sense as the entities he is supposed to explain. The multiverse may seem extravagant in sheer number of universes. But if each one of those universes is simple in its fundamental laws, we are still not postulating anything highly improbable. The very opposite has to be said of any kind of intelligence.”
— Richard Dawkins, The God Delusion, Mariner Books, 2008 p175-176
Martin John Rees, British cosmologist & astrophysicist, 1942-
"If there is a large stack of clothing, you're not surprised to find a suit that fits. If there are many universes, each governed by a different set of numbers, there will be one where there is a particular set of numbers suitable to life. We are in that one."
— Martin Rees, PhD, (quoted by Lee Strobel), A Case for a Creator, Zondervan, 2004 p145
