ABSTRACT
T H E N A T U R A L P H I L O S O P H Y OF L I F E were strictly necessary, but both suggested numerous questions which science could then proceed to investigate. If the atom is built like a solar system with electrons moving in orbit around a nucleus, we can ask how an electron can move from one orbit to another, or whether it can spin on its axis as, for instance, the world does. Science is often quite ready to tolerate some logical inadequacy in a theory-or even a flat logical contradiction like that between the present particle and wave theories of matter-so long as it finds itself in the possession of a hypothesis which offers both the possibility of control and a guide to worthwhile avenues of exploration.But although for these reasons one cannot make a sharp distinction between Man's effort to control and to understand the world, there is a considerable difference, at least in emphasis, between these two endeavours. Science which is motivated mainly by the desire to control the world will naturally study those aspects of it, the control of which would be most important in practice. The desire to understand, on the other hand, directs one's attention towards problems which have wide implications concerning the general nature of the world and of Man, even if his ordinary daily life does not urgently demand that he should control them. This might seem a less pressing reason for the development of science than the practical needs of human existence. Historically, however, it was the desire to understand rather than the need to control which led to the development of an orderly and organized body of thought and knowledge. The control of the material basis of existence was at first the province of the technician or craftsman, understanding that of the philosopher. The coming together of these two types of activity produced the first scientists. The predominant part which was played by the wish to understand the world was expressed in the original name of their activity, Natural Philosophy.As science has developed over the last few centuries it has of course provided us with powers of controlling our environment which were quite unthought of, and would have been quite inconceivable, by the early natural philosophers. So much so indeed that we tend nowadays perhaps somewhat to neglect the natural-philosophical aspect of science, and, when the word is
T H E N A T U R E OF L I F E mentioned, to think first of the triumphant manipulations of material things which have given us the automobile, the telephone, drugs, antibiotics, electric light and all the rest, including the atom bomb. But these products of science are essentially developments of the craftsman aspect of its nature. They are enormously important in practical affairs, in fact at the present time our whole life is built on them, and most of us could scarcely survive for a few days or weeks if they all suddenly disappeared; but they are based on enormously specialized and detailed understanding of particular types of process, and there is no very good reason why intelligent people in general should go into them very deeply. We should all, of course, have some inkling of what is meant by such scientific terms as hormones, or enzymes or electromagnetic vibrations or chemical valencies, but there is no reason why everyone should feel called upon to obtain even an outline understanding of modern developments in endocrinology, biochemistry, electrical theory or synthetic chemistry. In this set of lectures I shall not attempt to provide anything of that kind, but shall be concerned almost entirely with the natural philosophical aspects of biology, that is to say its contribution towards Man’s attempt to understand nature and his place in the system of living things.Before we start to discuss the problems of biology it will be as well to consider for a minute the nature of science in general. What sort of activity is it, and by what faculties of man is it produced? Even today there are too many people to whom the word suggests the 'bug-eyed scientist in a white coat’, or the animate calculating machine only by courtesy flesh and blood, who spends his time processing data according to the rules of an inflexible and almost super-human logic. But the ordinary scientist, or even the extraordinary one, is neither a 'commissar square’ nor a 'beat yogi’. He is not in the slightest a creature that stands outside the ordinary community of mankind. In fact, in many ways he is more than most intellectuals a social being.It is one of the most important characteristics of science that it is not the creation of one man, or even of a succession of individual men. Basically, in essence, and all through and through, it is something which has been produced by co-opera
T H E N A T U R A L P H I L O S O P H Y OF L I F E tive effort. An individual man can, of course, add a brick to the structure, or even lay out the plan of a new room, but his brick must be added to a wall which others have already partially built, and his new room must join on and communicate with the rest of the whole palace of knowledge. Science builds on and incorporates its past to a much greater extent than do any of the other major cultural activities of mankind. In painting, in poetry and the literary arts generally, the balance between originality and tradition is a very uneasy one. If, in the work of an artist, we see clear references to the work of his predecessors, we are likely to dismiss him as derivative. In science, unless we see that a man knows and respects what his forerunners have produced, we are inclined to find him unconvincing and ignorant. This communal, co-operative nature of scientific endeavour is one of its major sources of strength.It is important to realize how enormous that strength is. The scientific community is, I am afraid it must be confessed, a subversive organization; and successfully-some people would say too successfully-subversive. In those parts of the world where science has been vigorously pursued it has already destroyed the stability of a way of life which had lasted for many centuries, perhaps from the time of the Greeks and Romans until say three or four generations ago. This is, of course, a platitude. Everybody knows it and lots of people say it. But everiHjiat does not prevent it still being the most important fact in the world.The revolution brought about by science has not been due to the political activities of scientists. No country that I can think of has ever had a government the majority of whose members were trained as scientists; most of the countries we usually consider as civilized have been governed by men who were educated in the arts and humanities. The effects of science have been produced in a more subterranean way. Its effectiveness depends partly on the fact that it has found how to combine the efforts of many individuals into a single whole, but there is another point which provides a further reason for the enormous power of the scientific movement.Let me offer this rather far-reaching argument for your consideration and criticism. I suggest that science can be defined
T H E N A T U R E OF L I F E simply as the application, to questions concerning the external world, of all the major faculties which man is capable of exercising. Any complete piece of scientific work starts with an activity essentially the same as that of an artist. It starts by asking a relevant question, and that demands either or both of two things. The first step may be a new awareness of some facet of the world that no one else had previously thought worth attending to. Or the scientific advance may start from some new imaginative idea; ideas, for instance, like that of the quantum of energy, of indeterminacy, or lack of parity, or of a unit of biological heredity, or of the notions of releasers, displacement activities and so on, in which people are now analysing animal behaviour. These germs from which scientific work originates depend on a sensitive receptiveness to the oddity of nature essentially similar to that of the artist. When they are first proposed they" often have the same quality of unexpectedness, and perhaps wrong-headedjaess, as say, cubism, abstract art or atonal music.In science they have to be immediately followed up by the application of another of man's faculties, that for ratiocination. They have to be formulated in precise and probably mathematical language, and incorporated into a body of logical exposition. And then there comes a third activity, that of manipulation and the devising and carrying out of experiments. This is another stage which the scientist shares with the artist, but the latter, of course, leaves out the phase of logical analysis. And then in science there comes a fourth and final phase of the procedure, and this again is one which is usually much less well-developed in the humanities. In his logical analysis and manipulative experimentation, the scientist is behaving somewhat arrogantly towards nature, trying to force her into his categories of thought or to trick her into doing what he wants. But finally, he has to be humble. He has, as T. H. Huxley put it a century ago, to sit down before the fact like a little child. He has to take his intuition, his logical theory and his manipulative skill to the bar of Nature and see whether she answers yes or no; and he has to abide by the result.It is because science does all those things one after the other,
T H E N A T U R A L P H I L O S O P H Y OF L I F E and because they are done not by isolated individuals but cooperatively by the world community of scientists, that it has added, to our understanding of the world we live in, and indeed of ourselves, so much more than many centuries of reliance on pure intuition or pure intellect or on the kind of irrational activity found in magical systems.Living organisms are, of course, much more complicated than the non-living things which man encounters in his surroundings. Biology-the scientific study of living systems-has therefore developed more slowly than sciences such as physics and chemistry, and, as is inevitable in such a social activity as science, has tended to rely on them for many of its basic ideas. These older physical sciences have, on the whole, provided biology with many firm foundations which have been of the greatest value to it, but throughout most of its history biology has found itself faced with a dilemma as to how far its reliance on physics and chemistry should be pushed. Ever since our understanding of the physical world became tolerably satisfactory there have been some biologists who believed that their ultimate object must be to account for all the phenomena of life in terms of processes which can be discovered amongst non-living things. One can perhaps take Descartes as a representative of this point of view at the beginning of the modern period of science. He made a rigid distinction between the subjective phenomena of thought and feeling-—the res cogitans-and the objective observable phenomena of the material world-the res extensa\ and he argued that the latter, which includes the bodies of men and living things in general, must be fully explained in terms of simple material entities and strictly mechanistic principles. Opposed to this 'nothing-but' hypothesis of the bête machine there have always been other biologists, of whom one may take Harvey as the representative in Descartes' time, who believed that processes of life involve some vitalistic principle over and above the agencies which operate in the non-living world.Among the various types of vitalism which have been put forward throughout the centuries it is important to distinguish two main kinds. There is, on the one hand, a thorough-going vitalism, which might be referred to as 'objective vitalism', which
T H E N A T U R E OF L I F E claims that the phenomena which we observe in living things cannot be fully accounted for by means of the concepts which are adequate for the non-living world. For instance, Driesch was a prominent advocate of this view at the beginning of this century. He argued that the results of certain experiments, in which he cut eggs into fragments and found that each fragment had developed into a complete adult, could not be explained without invoking the activity of some non-material and nonmechanical whole-making active agent, which he called an entelechy. At the other end of the range of the vitalistic theories there is a point of view which could allow that all observable phenomena are potentially explainable in terms of concepts essentially similar to those of physics and chemistry, but which insists that phenomena of self-awareness-which we can never observe objectively, but only experience subjectively in ourselves-are of a radically different nature and cannot be accommodated within the same structure of ideas.The distinction which such theories draw is perhaps not quite the same as that between Descartes' res cogitans and res extensa. It is not that the processes of thought as such are completely excluded from the sphere to which a mechanistic explanation might apply. These processes have an aspect which is theoretically open to objective observation, for instance, by some very refined analysis of the electrical currents passing through various nerve cells in the brain. But subjective vitalists would argue that, even if we knew exactly what currents were passing through which cells when a given man thinks of a particular concept, there is no way of jumping the gap which separates our notions of electrical processes in material systems from the subjective awareness of an image, an emotion or an abstract concept. A large proportion of the workings of our nervous system and brain will proceed, as we well know, without our being aware of them; not only such processes of nervous adjustment as those by which we keep our balance when walking, but, as the psycho-analysts have shown, a great deal which has a character much more closely comparable to that which when it is conscious we know as thought. Thus, subjective experience does not seem to be an inevitable correlate of certain types of
T H E N A T U R A L P H I L O S O P H Y OF L I F E nervous activity, but appears to be something special; not merely an item which we have not yet allowed for in the conceptual scheme with which we account for observable phenomena, but something which lies in a different realm. Subjective vitalism is difficult to refute; I will have something more to say about it at a later stage in these lectures.In the last century or so it has been the conflict between mechanism and objective vitalism that has provided the main polarity between which biologists have ranged themselves. Even as recently as my own student days it seemed that the most important question facing a general biologist was to take some position vis-a-vis this great conflict of opinion. But actually at just about that time, or a few years before, the antimony between the two views was resolved, and the whole controversy evaporated. Objective vitalism amounted to the assertion that living things do not behave as though they were nothing but mechanisms constructed of mere material components; but this presupposes that one knows what mere material components are, and what kind of mechanisms they can be built into. In late Victorian times, in the heyday of the physics of Newton and Faraday and the chemistry of Dalton, people had a surprising confidence that they really knew what the world of matter consists of. Atoms and electricity seemed to be well known and completely comprehended things. It appeared quite natural to start from such certainties and to enquire whether they could or could not be used to explain the more complex phenomena observed in the living world. Those who thought they could, or at any rate should, were mechanistic biologists; those who thought they could not, were objective vitalists. A half-way house was represented by the theory of emergent evolution. This argued that when two or more simple entities come together in a particular arrangement they may gain new properties which they previously did not possess. For instance, it was suggested that when sodium and chlorine atoms come together to form common salt there emerges a new property of the compound which was not contained previously in the isolated atoms.It was, more than anyone else, the philosopher Whitehead who provided the new way of looking at the situation which de
T H E N A T U R E OF L I F E horned the dilemma. The physicists had, by the first two decades of the twentieth century, realized that atoms were not after all the hard billiard balls that their Victorian grandfathers had envisaged, and as the sciences of the inanimate world moved towards a theoretical structure in terms of relativity, quantum theory and indeterminacy, it became less and less plausible to suppose that there is any clear-cut mechanistic system of thought against which vitalism could rise as a reaction. It was Whitehead who put in general terms the point of view that this ancient dilemma arises essentially from seeing the situation upside down. It is not the case that we begin by knowing all about the ultimate constituents of the inorganic world, and can then ask whether they can account for the observable phenomena of biology. Always, whether in physics or in biology, it is from observable phenomena that we have to start; ultimate, or penultimate, or pen-penultimate constituents are what we hope to approach. It was one of the only too numerous aberrations of Victorian self-confidence to think that they knew enough about atoms to provide vitalists and mechanists anything to argue about.Whitehead's thought was certainly strongly influenced by that of the emergent evolutionists such as Alexander. In fact his ideas about biology can to some extent be regarded as emergent evolution seen from the other end. We start from a variety of observable phenomena, and from these we construct concepts (or models) of simpler entities, by combinations of which we can account for what we have observed. These simpler entities remain, however, mysterious things about which we know no more than we have been able to discover by inspecting the phenomena in which they take part. If we could observe the behaviour of sodium and chlorine only when each is in isolation, and if we regarded these two substances as made up of atoms, we might be able to discover something about these atoms, but not very much. There is no reason why we should expect to be able to become aware of the properties which allow them to combine with one another and form common salt. When this compound is formed, it is not that some new 'emergent' properties appear; it is simply that a new avenue is open to us for discovering a little more about the sodium and chlorine atoms.
