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  The lack of chance and the serving of ends are found especially in nature’s works. The end for which something has been constructed or has come about belongs to that which is beautiful.

  As an example from the other side, let us look at some fragments of Empedocles on the origins of humans:

  Empedocles believed that the first generation of animals and plants were not generated complete in all parts, but consisted of parts not joined together, the second of parts joined together as in a dream, the third of wholes, while the fourth no longer came from homogeneous substances like earth and water, but by mingling with each other.

  This leads to a rather nightmarish scenario:

  On the earth there burst forth many faces without necks, arms wandered bare bereft of shoulders, and eyes wandered needing foreheads.

  Many sprang up two faced and two breasted, man faced ox progeny, and conversely ox headed man progeny.

  Eventually, human beings with the ability to reproduce would be formed, and this process would come to an end. The problem here is that the Greeks had no concept of evolution, or of genetics. So those who believed that human beings came about by chance had to struggle very hard to come up with some sort of plausible account of their origins. If Plato and Aristotle found these accounts implausible, I think we may well have some sympathy with them. Plato, who was an excellent satirist, was savage about Empedocles’ view. He developed an account of how the demiourgos constructed humans with the best arrangement in mind. First the head is constructed, and then we are told that:

  In order that it should not roll around on the ground, with its heights and depths of every kind, and be at a loss in scaling these things and climbing out of them, it was given a body as a means of support and for ease of travel.

  Aristotle believed in the fixity of species. The cosmos had always existed, as had man and the animals. There was no evolution, and although nature did not deliberate, humans and animals were organised for the best. The teleological accounts of humans that Plato and Aristotle gave must be seen as at least as plausible as the mechanistic accounts of other ancient thinkers, in the context of the resources available in ancient Greece.

  There was another area of contention between Plato and the atomists. Plato believed that there were a small number of well-ordered basic particles out of which the physical world was constructed. As we have seen, he believed that there were two basic types of triangular particle which came together in various ways to produce the elements of earth, water, air and fire. Leucippus and Democritus, by contrast, believed there to be an indefinite number of shapes and sizes for their atoms. Plato explained the forms of his basic particles in overtly teleological terms. God created these particles because they have the best shape.

  While the scientific revolution adopted atomism and a mechanical account of the cosmos (rather like that of the ancient atomists), it is important to remember the following point. The scientific revolution occurred in a strongly Christian context, in which God created the cosmos ready formed, life ready formed, and was supposed to be responsible for the shapes and sizes of atoms as well. The problems with ancient atomism were resolved by supposing the existence of a God who orders things for the best, and so the influence of Plato and Aristotle was still felt. It was not until much later that theories of the origins of the cosmos and of life were able to do without such an idea.

  Remarkably, there is a similar debate in modern cosmology. The problem is slightly different, but the proposed solutions, in their structure, are rather like those pioneered by the ancient Greeks. We can now explain, at least in outline, the origin of the cosmos using gravity. According to modern cosmology, the universe began with the big bang around 15 billion years ago. After the initial expansion there was a period of rapid inflation, followed by a calmer period of expansion. At this time, there were the fundamental particles and there was a great deal of radiation, but none of the elements had formed as yet. This ‘chaos’ gradually sorted itself as the universe expanded and cooled. Firstly, hydrogen and helium nuclei formed, and then matter and radiation decoupled, with electrons binding to the nuclei of the light elements to form the first atoms. It is from this period, about 300,000 years after the big bang, that we can find evidence of the cosmic background radiation. While this is in remarkable accord with predictions, there are slight inhomogeneities. These small variations in the intensity of the cosmic background radiation, ‘ripples’, ‘wrinkles in time’ or whatever one wishes to call them, are the seeds for the future development of the cosmos. Clusters of matter form from these ripples and eventually create stars and galaxies. Stars burn their fuel of hydrogen and helium by nuclear fusion, creating the even-numbered elements up to and including iron. When these stars become supernovae, the other odd-numbered elements, and those heavier than iron, are created. Our solar system is formed out of the detritus of such stars. When sufficiently complex organic chemicals have formed, life gets under way and evolves, which brings us to the present day.

  This solves the ancient problem of how the cosmos acquired its order. There is, however, a different modern problem. We are aware that there are critical constants in nature, known as the ‘fundamental constants’. So, for instance, the intensity of gravity per unit of matter is a constant (the gravitational constant, G = 6.7 × 10−¹¹ Nm²kg−²), and the velocity of light is a constant (c = 3 × 108ms−¹). What we do not understand is why these fundamental constants have these specific values. Nothing determines that they have them, and they could have a whole range of other values. If these values were slightly different, our universe would be very different indeed.

  We know that the universe is expanding, and we also know that the rate of expansion is critically dependent on the value of the gravitational constant and the amount of matter in the universe. If gravity were significantly stronger, the universe would have collapsed long before the conditions for the origins of human life had come about. If gravity were significantly weaker, the universe would expand so rapidly that galaxies, stars and planets would not form.

  The carbon that is critical to carbon-based life-forms such as ourselves has not always existed. It was produced by a process known as ‘stellar nucleosynthesis’ in stars. In fact, all of the elements heavier than hydrogen and helium (the two lightest elements) are produced by stars. The production of carbon is part of a chain. Hydrogen atoms fuse together to form helium, then helium undergoes fusion to form beryllium (2He4 > Be8). The beryllium is short-lived, though, and very quickly another fusion reaction takes place between beryllium and helium to form carbon (Be8 + He4 > C12). The energy levels mean that this reaction proceeds quickly and very little beryllium is left. Some, but not all, carbon is eventually fused into oxygen (C12 + He4 > O16). This reaction is not so efficient, which means that some carbon is left unburnt. So, some of the elements are favoured in this chain – that is, a large amount of them is produced from the previous member of the chain, but relatively little is converted into the next member. Fortunately for us, carbon is reasonably well favoured. This is critically dependent on the energy levels in carbon atoms, which in turn are dependent on the strength of gravity and the electrical forces in the carbon atom. So our universe is critically dependent on the values of the fundamental constants.

  There is a split in modern cosmology. Some, rather like Plato and Aristotle, believe that we need some extra explanatory principles in order to explain why the one cosmos has these characteristics. Answers vary from there being a God who set the values of the fundamental constants in order that human life could come to exist, to some version of the anthropic principle. The anthropic principle is a sort of modern teleological principle which assumes that the cosmos must be such as to allow the eventual existence of humans. Others, rather like the ancient atomists, believe that our universe is only one among infinitely many others, the others differing in the values of their fundamental constants. The modern term for a collection of universes is a ‘multiverse’. There is a third approach to this probl
em which is distinctly modern rather than ancient. This approach says that we simply do not know enough about the universe yet, and that our physics is incomplete. Only when we have the complete physics, and we have a ‘theory of everything’ (a ‘TOE’), will we understand why the fundamental constants must have these values. It was a weakness of ancient science that each of the Greeks tended to believe that they had produced a final and definitive account of the cosmos, rather than contributed something to our knowledge in an ongoing programme of research.

  Figure 26: The modern cosmological problem. If the value of the gravitational constant is too great, then the universe will collapse again after the big bang and nothing interesting will be formed. If the gravitational constant is too low, then the universe will expand too rapidly for galaxies, stars and planets to form, and there will be no life. So does the gravitational constant have just the right value, and just the right relation to other fundamental constants, to allow the formation of galaxies, stars and planets – and ultimately life? According to some, we need further principles, such as the anthropic principle, to explain this, or perhaps we need to think of a God deciding on these values. According to others, our universe is just one part of a ‘multiverse’ of different universes, each with different values of the fundamental constants.

  Figure 27: The ancient cosmological problem. Why does chaos organise itself into a well-ordered cosmos (like that of Plato or Aristotle, shown here), rather than simply stay as chaos? Or, if a like-to-like principle is operating, why doesn’t the cosmos simply separate out into the constituent elements?

  Figure 28: The answer of Plato and Aristotle was that something more was required to explain how the universe was well-ordered. Plato saw good order as imposed by his craftsman god, the demiourgos, while Aristotle thought that good order, or the ability to develop towards the best order, was inherent in nature. The answer of the ancient atomists was that there were an indefinite number of cosmoi, some chaotic, some with partial order, and so the order of our cosmos had come about by chance.

  The origins of life are a different matter, since we now have a good account of both origin and evolution, the key mechanisms being genetics and DNA. However, these are relatively recent developments, and even after the scientific revolution, people struggled to give a convincing account of the origins of humans. During the seventeenth century, mechanical biology was developed, functioning on two levels. On a ‘macro’ level, it treated the body as a machine: limbs and muscles were levers and ropes; the circulation of the blood was a hydraulic system driven by a pump (the heart); and the stomach was a device for crushing and pulverising food. On a ‘micro’ level, the ultimate goal was to explain the functioning of the body in terms of the matter and motion of its constituent parts. Since matter was conceived to be passive, ultimately all explanation had to be in terms of immediate, mechanical causes.

  There were, however, certain very important phenomena that mechanical biology struggled to explain in anything like a plausible manner. Some of these were standard ancient objections, some were generated by the use of the microscope, newly invented by Leeuwenhoek. The basic problem for mechanical biology was that organisms appeared able to organise themselves beyond anything that mechanical biology could explain in terms of matter, motion and mechanical causes. This manifested itself in the question of reproduction, in which things as (mechanically) similar as equine and human embryos in things as (mechanically) similar as equine and human wombs would consistently grow into things as different as horses and humans. A further problem lay with the development of the human embryo, which in its early stages looks nothing like a human being at all, and seems to develop due to some internal dynamic rather than being determined by outside mechanical causes. The ability of some animals to regenerate significant body parts (such as some crabs), or reorganise into two new organisms after being divided (some worms), or reorganise themselves after being turned inside out (water hydra), also indicated a greater ability to self-organise than the mechanical philosophy could allow. A further blow to the mechanical programme was the discovery of the cell, thanks to the new microscopes. The cell appeared to be a living entity in itself, whereas the parts of the body were supposed to be simply mechanical.

  So mechanism could not account for the organisational abilities of animals and cells, nor their ability to pass this on. Even Aristotelian ideas of form and the actualisation of potential seemed to provide a better conceptual framework for understanding these phenomena than did mechanical biology. Biology in the eighteenth century therefore adopted vitalist ideas.

  The Greeks, and Aristotle and Plato in particular, are often criticised for their teleological approach. Yet it was a popular approach in the ancient world, and indeed for nearly 2,000 years up to the scientific revolution. It is easy to see why. Firstly, purely mechanical accounts were weak in the ancient world. The Greeks simply did not have the resources we now possess to explain the order that we see about us. Lacking a conception of gravity, they struggled to explain how the cosmos could have acquired its current order. Lacking any conception of genetics and DNA, or any serious idea about evolution, they struggled to explain how human beings might have originated. So we see a split between those who believed that these things came about by chance and postulated multiple cosmoi, and those who believed in a teleological ordering of the single cosmos. In that context, a teleological explanation looked at least as plausible as any other. Nor ought we to be critical of the Greeks for weak mechanical explanations, since people were struggling to make these work as recently as the seventeenth and eighteenth centuries. A Christian God was often the explanation of the order of the cosmos and the origins of life. It is only relatively recently that we have had a plausible explanation for the origins of life in solely physical and mechanical terms, and there is still a problem within modern cosmology, which splits scientists into ‘teleology’ and ‘multiple worlds’ camps, echoing the divisions of the ancients.

  6 Medicine and the Life Sciences

  Healing is a matter of time, but it is sometimes also a matter of opportunity.

  Hippocrates, Precepts, chapter 1 (translated by W.H.S. Jones, 1923)

  Virtually all societies have had some form of healing practice, just as virtually all have had some form of technology. The Babylonians and Egyptians had reasonable practices, and even possessed some rudimentary knowledge of the human body. It was the Hippocratics, though, who were the first to insist that all diseases had a natural cause, against the previous view that some, or indeed all, were of a supernatural nature. The first task of the healers in ancient Babylon, before any healing could take place, was to decide upon what sin had been committed, in order that the proper purifications and recompense could be made. This was in marked contrast to the early Greek scientists, who generally considered the cosmos to be an entirely natural place, and the Hippocratics, who launched a generalised attack on magical healing practices.

  In ancient Greece, there was no established medical profession, and there was a great deal of competition between the various healing practitioners. There were folk-healers, herbalists, magicians and purifiers, to name but a few. One aim of the Hippocratics was to establish themselves as the professional doctors, the people that any well-informed person would turn to in times of illness. So the attack on the supernatural was crucial in the founding of medical science and a medical profession. The Hippocratics claimed that they were the real doctors – the magicians were mere charlatans. They were very keen to insist that there was a proper science of medicine and that they were its practitioners, unlike their opponents or any ‘idiotes’ (the Greek for ‘laymen’, from which we derive the word ‘idiot’).

  The Hippocratics recorded marvellously detailed case studies, though they were not the first to do so. As the Edwin Smith papyrus (which recorded Egyptian medical practices) shows, the Egyptians also recorded cases quite carefully. However, the Hippocratic case studies were remarkable for their detail, their candour, and the fact that
they included negative outcomes as well as positive ones. They attempted to study many sufferers from disease, to see how the disease progressed and how various treatments worked. They were very keen on studying fevers, recording the days on which a crisis would occur that would then determine the course of the disease. They were careful to note such indicators as the patient’s posture, skin colour and temperature, the reactions of the eyes and the nature of the sputum, vomit, stools and urine.

  Admirable though these case studies were, they must be linked to the role of prognosis in the standing of a healer in the ancient world. The arts of diagnosis and prognosis were very important for the early doctor. As one of the Hippocratic writers tells us:

  If, when he visits his patients, he is able to inform them not only about the previous and present symptoms, but is also able to tell them about what will happen, as well as give further details they have left out, he will increase his standing as a doctor and people will not have worries about placing themselves under his care.