Lecture 7b: Cosmology and Theology
Necessary or Singular?
With the abandonment of the steady state theory and the uncertain future of the oscillating universe theory, those who are unable to accept the idea of a Creator have turned their attention to developing the concept of a necessary universe, that is a universe that must be the way that it is. If the universe is necessary, then there is no need to enquire why it is the way it is; it could not be otherwise and so there is no need to look for an explanation, in particular no need for a Creator.
The idea of a necessary universe has a long history, going back to Aristotle. As a scientific hypothesis it encourages the idea that it is possible to obtain the whole of science, including even the values of the fundamental constants, by pure deductive reasoning. There is no need to make experiments; physics, like mathematics, may be carried out by thought alone. Strenuous efforts were made along these lines by Eddington, but in spite of instructive insights, he did not succeed in his endeavours. The structure of the universe is far richer and more sophisticated than could ever be imagined by the mind of man.
But even if it is not possible to discover the structure of the world by thought alone, it remains possible that it is a necessary world. Due to the limitations of our minds we need the help of experiments to understand the order of the universe, and then we could realise that it is in fact a necessary order. The experiments serve as intellectual scaffolding that can be discarded when we have reached our goal.
There are indeed many features of the universe that might seem at first to be given, but which turn out on further examination to be necessary. For example the number of spatial dimensions must be three, for otherwise the solar system would not be stable. As science advances, more and more features of the world seem to be linked together and not at all arbitrary. Indeed the aim of theoretical physics is the unification of our knowledge of the world expressed inevitably in mathematical terms. Already the unification that has been achieved is remarkable, and areas of experience that seem to be quite distinct are seen to be but different manifestations of the same underlying order, as for example electricity, magnetism, optics and radio are all governed by Maxwell's equations. Great efforts are being made to unify the four fundamental forces of nature, and important progress has already been made.
It is quite possible that scientists will eventually succeed in developing a comprehensive theory that explains all phenomena and enables the results of all conceivable experiments to be calculated. Even this, however, will fall short of proving that the universe is a necessary one, as a consequence of a theorem of Godel, who showed in 1930 that no set of non-trivial mathematical propositions can have its proof of consistency within itself, and that there are always meaningful propositions that cannot either be proved or disproved within the system. Thus any scientific cosmology, which is necessarily expressed in mathematical terms must fall short of being a theory that shows that the world must necessarily be what it is. There is always the possibility of the surprising, the unexpected, that points beyond this world for those who have eyes to see.
The Singularity of the Universe
The more closely scientists study the evolution of the universe the more evidence they find of its extreme singularity. A striking example of this has already been quoted: if the proportion of nuclear particles and photons had been slightly different there would have been nearly all hydrogen or nearly all helium, and in each case no heavier nuclei and so no possibility of life. Again, it has been noted that the universe is remarkably homogeneous on a large scale, and this is the result of the initial conditions. It is very difficult to understand why these inhomogeneities should be so small, and yet if they were any larger the matter of the universe would have collapsed into black holes long ago, while if they had been any smaller, there would have been no galaxies.
The evolution of the solar system is also highly specific. There is still no satisfactory theory of how the system of planets was formed, and in particular how they came to be rotating around the sun in nearly circular orbits, and nearly in the same plane. Yet it is only on a planet of a certain size moving on a nearly circular orbit that life could have evolved. The more this evolution is studied, the more we realise that it is immensely improbable that we should be here at all. We have come to where we are on an exceedingly narrow track.
Man in the Universe
We always tend to think that we are at the centre of all things. The ancient Hebrew cosmology, the cosmology of the Greeks, and cosmology of the Hindus all put man in the centre of the universe. In Genesis man appears as God's supreme handiwork on the sixth day, and all creation is his to dominate. This anthropocentric picture received a crushing blow when Copernicus showed that the motions of the planets can be much better understood if they rotate about the sun, so now the sun is the centre, with the earth a rather small planet revolving around it. Man's centrality received further blows when it was shown that the sun, so impressive to us, is a rather undistinguished star near the end of one of the spiral arms of a vast galaxy of billions of such stars, and that this galaxy is but one of many billions of similar galaxies scattered through an unimaginably large universe.
What remains of the centrality of man, and of the world made for him by God? Compared with the vastness of space, we are totally insignificant. We can be filled with awe and reverence, and with the Psalmist we can rejoice that the Heavens show forth the glory of the Lord. Or, with Pascal, we can be terrified by the vastness of space, realising that 'man is but a reed, the most feeble thing in nature. The entire universe need not arm itself to crush him; a vapour, a drop of water, suffices to kill him.'
It is true that we can reply, again with Pascal, that man 'is a thinking reed. If the universe were to crush him, man would still be nobler than that which killed him, because he knows that he dies, and the advantages the universe has over him; of this the universe knows nothing.' But how can we be sure even of this? Is it not very likely that around some other stars in far away galaxies there are sentient beings in civilisations immeasurably superior to our own, who know what we are doing and regard our activities in much the same way as we regard those of ants and bees. There are indeed few grounds for pride when we consider our position in the universe. And if there is no other life in the universe, this raises another question, posed by Margaret Knight, a well-known humanist: 'If life is the purpose of creation, what conceivably can be the point of countless millions of lifeless worlds? Or of the aeons of astronomical time before life existed? The Church has glanced uneasily at these questions but it has never answered them.' In saying this she was but echoing Maimonides' Guide for the Perplexed: 'Consider then how immense is the size of these bodies, and how numerous they are. And if the earth is thus no bigger than a point relative to the sphere of the fixed stars, what must be the ratio of the human species to the created Universe as a whole? And how then can any of us think that these things exist for his sake, and that they are meant to serve his uses?'
Now, when we know far more about the universe, when we begin to understand in a very detailed way the evolution of the very matter of which it is composed, we begin at the same time to glimpse a new truth, that it looks more and more as if the universe was indeed made just for man. At each stage in its development there seem to be many possibilities, and every time the one is chosen that alone leads to a universe that can produce man. Within this perspective the insignificance of man takes on a completely different aspect. We wonder at the vastness of the universe in space and time compared with the smallness and frailty of man. Why this apparent prodigality? Now we see the answer: all this stupendous evolution was necessary in order that the earth should be made as a habitation for man. The process of nucleosynthesis, by which the elements constituting man's body are built up in the interiors of stars, takes billions of years. And in this time the galaxies containing these stars will inevitably move vast distances from their point of formation. So the universe must be as large and as old as it is, in order that it can be prepared as a home for man.
This is why we can say that it is our universe. Freeman Dyson has summed this up in the words: "As we look out into the universe and identify the many accidents of physics and astronomy that have worked together for our benefit, it almost seems as if the universe must in some sense have known that we were coming."
The idea that the universe has taken just that path in its evolution that leads to man is called the anthropic principle. It must be noted that this principle does not explain why the universe evolved in this particular way, unless we already believe in a Creator who intended this result. Since we are indeed here, then of course the universe must be such as to allow our emergence. If the universe had so to speak taken the wrong turning, then we would not be here to talk about it. Or perhaps there have been millions of different universes in non-interacting spaces, and this is just the one that happened to be such as to allow for the evolution of man. We may or may not think that these arguments are plausible, but they are certainly tenable.
It has sometimes been objected that the anthropic principle is not scientific because it is not testable and leads to no new discoveries. However, Hoyle considered how carbon could be formed, and concluded that it must be by the simultaneous collision of three alpha-particles. The probability of such collisions is extremely small, and so the cross-section can only be appreciable if there is a resonance just above the state in carbon formed by three alpha-particles. He looked at the spectrum of carbon and found that there is indeed a resonance at just the required energy.
There is an even stronger form of the anthropic principle that deserves mention. We are accustomed to think of the constants of nature like the velocity of light or the mass of an electron as fixed and unalterable. Now the strong form of the anthropic principle says that the values of these constants are in fact fixed by the requirement that the universe will allow man to evolve. Some rather detailed arguments have been made to support this idea. This raises the possibility that there are many universes with different values of the fundamental constants, and only those with the values we know can produce man. There is however a difficulty with this argument. The number of fundamental constants is about ten, whereas the number of conditions they must satisfy is substantially greater. This implies that it is not possible, even in principle, to fix the parameters so as to ensure the evolution of man; there are not enough of them. The values of the constants cannot be the result of a random process; the universe is our universe, at the deepest level.
It should also be remarked in connection with the anthropic principle that it is possible that when science advances further we shall see that what appear to be arbitrary choices in the evolutionary process are in fact necessary. That, for example, we might find that the ratio of nuclear particles to photons must be as it is, and similarly for the other apparently very singular parameters. At an even deeper level, the very values of the fundamental constants as we know them might be necessary values, as indeed Eddington tried to show. This would make it even more surprising that we are here.
Although the emergence of life in the universe seems to be a most improbable process, there are so many stars that might conceivably have planets on which life could have evolved that there have been many speculations that conscious beings and perhaps well-developed civilisations exist in many parts of the universe. This has led to ambitious schemes to detect signals that may have been broadcast by such beings, and plans to transmit signals of our own. However until we have factual evidence the whole subject is highly speculative, serving to distract attention from real and solvable problems.
Random or Ordered?
There are two contemporary lines of argument that appear to support the idea of a purely random world, one derived from quantum mechanics and the other from the recent work on chaotic motion.
Quantum mechanics was developed in the nineteen twenties and has been extremely successful in accounting for a wide range of atomic and nuclear phenomena. It is an indispensable part of modern physics. There is however still much dispute about its interpretation, and this is essentially a continuation of the dispute between Bohr and Einstein.
The most important point of difference is that Bohr held that the wavefunction contains all that can be known about each individual system, whereas Einstein held that the wavefunction gives only the average behaviour of a large number of similar systems. Since individual systems behave differently, even if as far as we know they have been prepared in the same way, then according to Bohr they manifest a radical indeterminism. That is what led Heisenberg to say that the law of causality has definitely been disproved by quantum mechanics. Within this perspective it is possible to say that there is no reason to seek the cause of the universe. This denial of causality fails to distinguish between the inability to measure exactly and the objective existence of exact quantities. Einstein however would say that the systems differ because they were different from the beginning, and thus it is quite possible that the world is a fully determined system, although we cannot prove that this is so.
The difference between the two views is thus primarily ontological. Einstein held that there is a really existing objective world that we try to study using the methods of science. We do not yet know all that there is to know, and if there is any apparent indeterminacy then we may be sure that there is some underlying determining process that we may one day hope to discover. Bohr, on the other hand, held that 'it is wrong to think that the task of physics is to find out how nature is. Physics concerns only what we can say about nature.' We see here very clearly how a positivistic stance weakens our grasp on the objective reality of the universe, and leads us to infer a spurious indeterminism. It is not surprising that another fruit of the Copenhagen Interpretation is the misuse of the Heisenberg Uncertainty Principle to explain the production of matter out of nothing. Even more bizarre is the claim that the universe can exist only because of the presence of an observer, necessary to collapse its wavefunction.
The other line of thought that has strengthened the general belief in the randomness of the world is that connected with what is called chaotic motion. We are familiar with the idea that if we know the initial conditions, then application of the laws of physics enables us to calculate the subsequent behaviour. If, for example, we know the position and velocity of a planet, then using Newton's laws we can calculate its subsequent motion. Recent studies have however shown that in many systems the motion is exceedingly sensitive to the initial conditions. A very slight change will soon lead to completely different behaviour. For example, if we try to calculate the motion of molecules of gas that are continually colliding with each other, then the motion after a collision depends sensitively on the initial trajectory, and so a very small change may easily determine whether a subsequent collision takes place or not.
The effect of this is that it is impossible to predict the future behaviour of such systems. All measurements are limited in precision, and the imprecision of our measurement is always such that our calculations of the future behaviour of a system very soon become quite unreliable. Once again it is an ontological matter. Because we cannot predict the behaviour of a system it does not mean that the system is undetermined or random.
Thus whenever we hear talk about a process that is described as chance or random, this refers to the way it is described mathematically, not to its intrinsic nature, which is strictly determined. We cannot prove that this is so by the methods of science; we know it from the Christian doctrine of creation, on which all science is ultimately based.
Creation from Nothing
There have recently been many speculations about the possibility of providing a scientific explanation of creation itself. The first difficulty is to know whether the laws of physics still apply. It is always possible to invoke the power of God, but it is the duty of the physicist to try to solve problems by scientific methods alone. Thus it might well be thought that creation requires the violation of the conservation laws, but it seems that this is not necessarily the case. There is no difficulty about the total electric charge and angular momentum, since these have values consistent with zero, and the total linear momentum is not definable. The main problem concerns the principle of conservation of energy, and it was realised that the negative potential energy of the universe could exactly balance its positive kinetic energy, so that the total energy of the universe is just zero. So there is no need for God to override the conservation laws during the creation of the universe.
Vilenkin has suggested that the universe could come into being by quantum tunnelling from nothing; this assumes that quantum mechanics can be applied to the whole universe, an assumption that rests on a discredited interpretation of quantum mechanics. Hawking has suggested that time, like space, has no boundary. There is thus no initial singularity, no moment of Creation. Thus 'the boundary condition of the universe is that it has no boundary. The universe would be completely self-contained and not affected by anything outside itself. It would be neither created nor destroyed. It would just BE.' This proposal has the merit that it does not require an initial singularity where the laws of physics break down. However he also supposes that if there is no beginning, then there is no need for a Creator. This is a misunderstanding of the nature of creation, which is the causing of existence, an activity that is continuous. The continuation in existence requires God's causal agency just as much as the initial beginning, so even if there is no initial singularity the creative act of God is still necessary.
It should be remarked that the physicist's concept of the vacuum is quite different from that of the theologian. For a physicist, a vacuum is rich in potentialities, but even then it requires an external agency to cause anything to happen. The theologians' vacuum is absolutely nothing at all, no matter, no space, no time and no potentialities of any kind. From that nothing, nothing can come. The physicist's vacuum, however, needs to be created.
Some attempts have been made to give a scientific account of creation out of nothing by a chance process. Chance is referred to as if it is a causative agent, not as indicating unknown causes. There is a more general difficulty: all a scientific theory can do is to say that if there exists matter with such and such properties that obeys certain equations, then if it is started off in a particular configuration it will behave subsequently in a way calculable from those equations. What it cannot say is whether there indeed exists matter with such and such properties, and how it is put into a particular configuration and no other. As Hawking asked, "what is it that breathes fire into the equations and makes a universe for them to describe?" And who sets the initial conditions? Furthermore, a scientific theory is only reliable in the regions where it has been thoroughly tested; when it is extrapolated to other regions its predictions must be less certain. And what is more unpredictable or more singular than the moment of creation?
Another point worth noticing is the way creation is associated with the very simplest structures. Thus Atkins has remarked: "The creation can generate only the most primitive structures, structures of such simplicity that they can drop out from absolutely nothing." But it must be said that, simple or complicated, small or large, the passage from non-existence to existence is the most radical of all steps. It cannot be glossed over, and no one with any sense of ontological reality could accept this for an instant. However large or small the object may be, the passage from non-being to being is the greatest possible transition. We are talking about creation itself, and that is an activity that belongs to God alone.
Cosmology remains highly speculative, with many new theories but insufficient data to test them thoroughly. One of the most recent is the instanton theory proposed by Hawking and Turek. An instanton is a 'sort of Jump which couples gravity, space, time and matter together', 'a twist in matter and spacetime'. It forms the rounded top of the spacetime cone at the initial singularity of the Big Bang. In this region the distinction between space and time is blurred. The authors of this theory have been asked what are the implications for the existence of a Creator, and have replied that there are none. However, they add, with remarkable confidence, that 'if a divine being wanted to create a universe, the simplest way to do it would be to use our instanton'.
Following the COBE satellite in 1992, the Micro-Anisotropy Probe is scheduled to be launched in 2000, and the Planck Explorer in 2005. These should provide extensive data to test the wide range of current cosmological speculations. Turek comments that 'cosmology is on the threshold of turning into a science', and is confident 'that an understanding of the beginning of our universe is within sight'.
All these scientific developments show in ever-increasing detail the awesome extent and wonderful complexity of our universe. Beneath this complexity we are finding a unified structure, so that the discoveries of nuclear and particle physics can enable us to calculate in detail the processes that took place billions of years ago and eventually spread out over unimaginable distances. Thinking about this can increase our reverence for the power of the Creator. However, as many examples have shown, it is always unwise to base any arguments for the existence of God on particular scientific results. Very often what has seemed at first to have been a remarkable coincidence suggesting a supernatural cause has be shown by further work to be entirely explicable by the laws of physics.
The story of our attempts to understand the world thus shows a complex interaction of theological beliefs, scientific observations and theoretical speculations. It is notable that it was Christian theology that made science possible in the first place. and with it all the vast development that has led to our modern understanding of the universe.
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