In his preface, he discusses the anthropic principle, which is essentially the view that the structure of the universe is such as to make it suitable for life. Strictly, this proposition is the weak anthropic principle. The strong anthropic principle is more controversial in suggesting that the universe has to be like that, rather than just being like it by chance. Davies remarks on the way in which the scientific establishment has gradually gone from viewing the anthropic principle as semi-mystical mumbo-jumbo, to seeing it as a life line alternative to intelligent design, in the face the apparent fine-tuning of the universe.
Much of the book is taken up by the discussion of various versions of the multiverse, a concept now widely promoted as an alternative to intelligent design. In respect of the multiverse idea, Davies discusses the question of the observable universe. Present technology can see about 10bn light years out from Earth, but in principle it should be possible to see 13.7bn light years out. That is the limit of the observable universe, because light would not have had time to reach Earth from more distant regions. Davies points out that galaxies at the limit of the observable universe having been moving away from Earth since the light we are now seeing left them, and would now be nearly 28bn light years away. Further to this, we can see out in all directions from Earth, so the width of the observable universe is twice whichever of the above figures is chosen. Davies points out that these distant regions in opposite directions from Earth would not have any contact with one another, because light or anything else would not have had time to pass between them. They are effectively part of different universes. The same rule applies to parts of the universe that are a long way out from Earth. They would be in contact with parts of the universe that could not be in contact with Earth.
All this appears relevant to one version of the multiverse discussed at some length in this book. This idea is not so much a multiverse, as a single universe split into a huge or even infinite number of domains with different laws of physics. The different laws arise by chance out of the initial Big Bang, and the huge number of domains brought into existence makes it quite probable that one or even a few of them would have laws of physics suitable for the emergence of organic life. However, this proposition seems to give rise to significant problems. In the first place, it appears to violate Occam’s Razor, a scientific principle that favours the selection of the simplest or the most established theories. As far as we can tell the same physical laws operate throughout the observable universe even near its boundaries, and the simplest assumption is that those laws continue to apply throughout the universe that lies beyond the observable boundaries.Occam’s Razor is not the only problem faced by the multiple domain idea. Although Davies does not discuss this, it would seem to be necessary to look at what happens at the boundary between domains. What would happen if neighbouring galaxies to the Milky Way had different laws of physics? It might be argued that a huge area of empty space would be inserted between galaxies with different laws, but this looks much too convenient and orderly given that the whole system is supposed to have arisen by chance rather than design.
The problem has echoes of the argument against dualism. Dualism is the view that spirit is a separate stuff from matter and accounts for mind, God and possibly other entities. It is ridiculed by most scientists, and the core of their argument against it is that it would be difficult for spirit to interact with matter without sharing some of the physical properties of matter. There seems to be hints of the same problem in the idea of domains with different laws of physics co-existing within the same universe.
Some of the best parts of this book are those in which Davies discusses the extent of fine tuning in the universe. The actual power of the Big Bang itself proves to be fine tuned to be favourable to life. A more powerful bang would have dispersed the cosmic gases too widely for them to subsequently aggregate into the stars and galaxies necessary for life. A less powerful Big Bang, however would have allowed the universe to fall back into a black hole.
Another convenient circumstance arose in the first few minutes after the Big Bang, with the weak nuclear force being set at just the right level to give a favourable balance of hydrogen and helium atoms. Later on when stars form, helium atoms become important for life, because they are able to fuse together to produce carbon atoms. However, hydrogen is also vital as the basis of stars, which are also essential for life.
Davies moves on to look at what happens inside stars, which also proves to be a crucial area for making the universe suitable for life. A lot of helium atoms were created in the aftermath of the Big Bang, but another tranche of helium was created inside stars. In fact, stars derive most of their energy from the fusion of hydrogen into helium. However, the fusion of helium in stars uses a slower route than in the aftermath of the Big Bang. This latter process is controlled by the weak nuclear force. This makes the process slower than in the Big Bang, and this in turn allows stars to burn for sometimes billions of years giving organic life the time to emerge and evolve on neighbouring planet(s), another convenient circumstance for organic life.
Another remarkable convenient (for organic life) circumstance emerges when higher-mass stars start to run out of hydrogen. They have sufficient internal temperature to fuse atoms larger than the hydrogen atom, but the next two atoms in weight, lithium and beryllium would not be stable under these circumstances. The next heaviest atom is carbon, but for this to be fused inside a star three helium nuclei have to come together, and at first sight the odds against this look high. However, it has been found that carbon has a resonance that is just right to allow the fusion of three helium nuclei. This resonance is determined by the interplay between the strong nuclear force and the electromagnetic force. It is this that allows carbon, fundamental to living organisms to be plentiful in the universe. If the strong force were only 1% weaker, this resonance would not work, and carbon would not be plentiful. Again this is another piece of fine tuning that is extraordinarily convenient for organic life.The weak nuclear force becomes important for organic life again when larger stars explode in super nova. These are important for disseminating carbon and the other heavier atoms into space, from whence they can eventually come to be present on a planet suitable for life. In this process, the weak nuclear force has to have very close to the strength it actually has for the neutrinos released in the process to not have sufficient strength to react with the stellar core, but to have sufficient strength to explode outwards from the star. Again this is a very convenient piece of fine tuning.Davies also looks at the convenient relationship of the strengths of the electromagnetic and gravitational forces. The electromagnetic force is 1040 times stronger than the gravitational force. A child’s toy magnet can lift a paper clip, and when it does, it outweighs the gravitational force of an entire planet. It turns out that this relationship is necessary to allow smaller stars to run on heat convection, which appears to aid the formation of planets, while large stars rely on radiating energy, which in turn creates conditions suitable for super nova. Both planets and super nova are essential for organic life.The structure of the universe appears to be littered with yet more convenient coincidences. The neutron has a slightly greater mass than the proton. If the tables were turned, it would be the proton that decayed into a neutron, and there would be no atoms, no chemistry and no life.The cosmic microwave background radiation contains ripples that probably originated in quantum fluctuations, and were the basis for the later formation of galaxies. If the size of these ripples were even slightly larger or smaller the formation of life bearing galaxies would be disrupted.
In discussing the multiverse, Davies feels that this concept has only been partly successful in getting rid of the need for intelligent design. He suggests that it has simply shifted the problem from explaining the universe to explaining the multiverse. Inflation, originally thought up to explain the thermal equilibrium of the early universe, is the basis for presupposing the creation of many universes out of quantum fluctuations during the process of inflation. The problems come with inflation itself. This pre-supposes something that generates a universe in the Big Bang, plus the quantum laws and the laws governing gravitation and spacetime, which needed to be fine tuned themselves to produce inflation.
Davies feels that much of mainstream cosmology is too dismissive of both life and with it consciousness, as something happening on the surface of an obscure planet, with no great importance for the universe as a whole. However, Davies passes over the chance to explain the origin of life as something related to the laws of physics. He argues that life is 1% physics and 99% environment. However, while the evolution of organisms as a function of their environment is quite well understood, the actual origin of life is not, because of the enormous chances against a soup of organic molecules turning into a basic replicator, the start point of life.
There seems to be an opportunity in this book, to speculate that something like the way that laws of physics, against all the odds, make super nova disseminate carbon and other heavy atoms, might also apply in the pre-origin of life relations of organics molecules. Some researchers have suggested a form of quantum search engine that eventually lights on the right combination for a replicator. However, Davies does not enquire into this area.
Despite this, Davies still toys with the idea of a law-like trend towards life in the universe. Davies’s seeks a quantum route to this. He goes back to the most basic of quantum experiments, the two slit experiment. Here a beam of light passes through two slits in a screen, before falling onto a second screen. The image will appear in the form of light and dark bands. This demonstrates the wave-like nature of light, because the pattern shows that waves from the two slits interfere with one another.
As technology advanced this experiment was refined. Instead of a beam of light containing countless photons, photons were fired one at a time. The really surprising thing was that an interference pattern still gradually formed, although the photons had no conventional information about the photons that had gone before them, or the ones that would come after them. However, if a photon counter is placed at one of the slits, the quantum wave function collapses, the waves become particles and the interference pattern disappears. Possibly the most common explanation of this puzzling behaviour is that as a wave the single photon passes through both slits and interferes with itself.
Davies discusses a further refinement to this experiment devised by the physicist, John Wheeler. He changed the second screen into a Venetian blind and placed detectors behind this blind, and pointing at the slits in the first screen. If the Venetian blind is closed, the experiment is seen to proceed in the normal way. However, if the blind is open, light photons pass through it, and the detectors can find which slit in the first screen the photons went through. As a result of this observation the photons become particles. The experimenter can choose whether or not to direct the detector at the slits, and thus whether or not to get waves or particles. However, the final stage is to delay the decision whether or not to detect the particle until it has reached the Venetian blind. In this case, the particle does not ‘decide’ on whether to take the wave or the particle form until it ‘sees’ the detector, but this is after it has already passed through either two slits as a wave or one slit as a particle.
The experiment thus delivers an apparent backward causation in time. To makes matters still worse, Wheeler extended this actual experiment to a thought experiment. Supposing the photons came not from a lamp in a laboratory but from a distant star, with photons in a superposition of passing round both sides of an intervening galaxy. If these photons eventually arrived at Wheeler’s Venetian blind contraption, the decision as to whether to pass on one side of the galaxy as a particle or both sides as a superposition could be referred back in time by billions of years to a period before the Earth even existed. Wheeler and Davies with him seem to favour the idea that conscious life now could have a backward causation effect stretching to the Big Bang, and creating a closed loop of cosmos–life–cosmos.
I have to say that I am not very taken by Wheeler’s proposition in terms of explanatory power. While it might be arguable that existing life forms could exert some backward causation, this does not explain how the first life forms intelligent enough to exert backward causation came into being. On the basis of the rest of the book, these first backward causers would never appear without the whole paraphernalia of fine tuning, which backward causation is supposed to explain.
The main virtue of Davies’s approach may be to open the door just a crack to the involvement of mind in the development of the universe. It would seem possible to do without a thunderbolt throwing type of God, but still allow some involvement of mind in the laws of physics. (See, Mind-Like Universe)