CHAPTER IV

_An Evolutionary Experiment_

Questions are often made unnecessarily difficult by their being expressed in an abstract or theoretical form, and instead of asking What is life? it will be more valuable to put forward a practical issue for discussion: Could an infinitely wise physicist order the necessary chemicals to-day, and to-morrow put together a synthetic man? If not, why not? What are we really up against, that seems to put some aspects of life beyond our control?

Let us watch this ambitious physicist as he enters his laboratory. He has started quite easily and has in a moment prepared some simple molecules from their elements. Now he has completed the first colloid that he will require, and is starting on his first organic synthesis. But his infinite wisdom does not give him eternity within a minute, and we notice that he is getting on more slowly. While the actual combination of the first molecules took only about a thousandth of a second, once he had the apparatus ready, the simplest colloid took about a second. The organic colloid has taken him about a minute; it seems that nature won’t work faster than that. She has her own rhythm and won’t be rushed. If we wait patiently till the end of the day our friend may have his first speck of protoplasm, and all the skill in the world would only have helped him to make more of it, not to have got any further in his game of evolution.

But look at him now! He is making a hasty calculation as though he had just realized some great secret of nature, and knew that he could never create his homunculus. We look over his shoulder and read:

_Estimated minimum time required by the synthetic processes of nature to attain various evolutionary stages._

Starting from the Minimum elements, to Time

Simple inorganic compound 1/1000 sec. Simple colloid 1 sec. Protein 1 hour Primitive protoplasm 1 month Simplest uni-cellular organism 10 years Flagellate 1,000 years Mammal, including _Homo sapiens_ 1,000,000 years

This highly speculative estimate is based on suggestive facts. A certain amount of time is necessary for two atoms to approach one another and form a molecule. The time required will be greater if many atoms have to settle down together into some special arrangement. For instance, the metal silver is normally crystalline, but if silver vapour is condensed too quickly the atoms will not have time to arrange themselves, and it is found that they pile up anyhow into an amorphous mass.

Colloidal processes require even longer periods, because great clumsy molecules have to arrange themselves on the surface of the colloidal particles. In elementary forms of protoplasm the molecular patterns are still more complex, and yet more time must be necessary to get the molecules properly adjusted.

It is probable that only our ignorance prevents us from building up protoplasm, but that we shall require rapidly increasing amounts of time for each successive stage of evolution. This will certainly be the case when we have reached organisms which can only be rendered more complex by controlling their environment while they reproduce themselves for many generations. A higher organism cannot be built up directly; the molecular arrangements in its body can only be reached through the synthesis of some simple form of life which must then be allowed to evolve through countless generations. Organic heredity resides in molecular patterns which can only be built up by this very slow process of repeated reproduction. Thus it is _shortage of time_ that our ambitious scientist is up against in his haste to create a homunculus. Only the synthetic alchemy of time can build up organisms, each bearing within itself a long heredity.

The estimates given for the minimum time required in each case are about a thousandth of the actual time taken in a laboratory experiment or in the history of evolution as known from geological records. It may have taken a million years or more for the first mobile cells to have developed from inorganic materials and a thousand million years for the mammals. Yet perhaps these processes might have gone on more quickly. The times given are mere suggestions of a minimum time which may be necessary under ideal conditions. We waste a lot of time adjusting the apparatus in a laboratory experiment, and in evolution there may have been stationary periods with little or no new development. But it seems likely that when we know more about it we shall discover that a certain time is required for the formation of organic systems of given complexity. In this sense we may say that then human spermatozoon and ovum carry within them the synthesis of at least a million years.

Only an International Institute of Evolutionary Research under the most stable of Leagues of Nations could hope to create an artificial man, and even then man could hardly take the credit, for Time would have done more than man. But with sufficient consistency of purpose man could do this, provided he learnt how to make use of every moment of the creative power of time, and never made a slip by which the accumulated treasure of the years (i.e. heredity) might be broken. How man would learn to value life, and how profoundly such an experiment might alter his view of human beings, each one a priceless miracle, fruit of a million years!

In twenty years’ time scientific knowledge will be adequate for the beginning of this giant task, and we shall be subscribing our guineas for the foundation of the Institute. Time has created man; man may use time to create man once more. With a million years ahead of us before we reach the sensitive mammals, we need hardly fear criticism from the Society for the Prevention of Cruelty to Animals. We are simply going to allow life to evolve itself under ideal conditions with Switzerland as the State for Evolutionary Research.

It may happen that under such perfect conditions life will evolve more swiftly than it did on this rough-and-ready planet. But equally well we--or rather our descendants--may find that the Darwinian struggle for survival is essential for evolution, and then the nations would have to debate on the morals of reproducing the ‘cruelty of nature’ inside the World’s Evolutionary Zoo. Perhaps a wrathful god will seek to punish mankind for attempting to build this ladder to the secret of life, this modern Tower of Babel, and amuse himself by watching the community of scientists stricken by a plague of inconsistency amongst their weights and measures.

The possibilities of such grand schemes have to be taken seriously. We are now highly self-conscious beings with a tremendous technique for research. Men with genuine creative imagination who reverence life must shoulder the responsibilities of the twentieth-century consciousness, and use scientific technique for creative not life-destroying purposes. One can imagine a growing fraction of the interest now given to war, other people’s adultery, and greyhound racing, turned towards Switzerland, whence at critical moments wireless bulletins would announce that the first amoeba had just successfully taken nourishment. If we wish it, the future of science can be such as to recompense for its recent occupation with gunpowder. Governments would be powerless to make war if the physicists refused to make the guns and the Royal Society called upon scientists to go on strike until each war crisis had been settled by arbitration.

The problem of life may be seen in a new light if the speculations of the last section are accepted and we assume that a definite period of time is necessary for the building up of any living organism. For if this is so the laws which govern life must involve the age of the organism since some definite moment in its history. We might choose for this moment the instant when the parent spermatozoon entered the ovum in the case of a higher organism, or in the evolutionary experiment just described the age might be reckoned from the moment when the first elementary chemicals were combined into molecules. The point is that this whole evolutionary process must be described by laws which take into account the age of the system under consideration.

Let us take a very simple, indeed the simplest possible, example. If two hydrogen atoms having just the correct total energy for the formation of a hydrogen molecule have approached one another and combined, the law describing what has happened must indicate that at a definite moment the combination was complete and the process at an end. This is an example of an irreversible process, since the molecule does not _spontaneously_ break up again. Moreover, the mathematical formulation of this process must include the definite age of the system at which the process was complete, this age being measured from some selected initial moment.

This process provides an interesting limitation to a principle put forward by Maxwell as the basis of physical science. He suggested that the laws of physics must be considered to be eternal and unchanging and that therefore they must be expressed in a form which does not contain the time explicitly. This means that for physical laws there can be no difference between to-day and to-morrow. The laws are concerned with small changes which systems undergo in small time intervals, and need not express any fundamental distinction between one moment and another.

Such laws cannot express the fact that anything sudden ever occurs which makes an essential change in the system as when two systems become one, or when one system breaks up into two. The laws of organic growth or the evolution of individual systems must display the fact that at a certain age of the system special things happen, such as the combination of two hydrogen atoms, or the attainment of maturity by an organism. Maxwell’s principle puts a limitation on the form of physical laws which precisely eliminates the laws that would be appropriate for organisms. But there is no reason why a broader physics should not try to frame this new type of law that would be applicable to the history and development of individual systems, and it is probable that if this could be done the reversible laws of Newton, Maxwell, and Einstein would appear as approximations which were valid when nothing of special interest was happening, i.e. when only spatial movements were involved without synthesis, disintegration or the emission of light.

Laws of the Newtonian type which Maxwell had in mind assume that one can adequately describe the present state of a system without specifying its past history. But we cannot say anything very precise about the inside of a living organism, and it is found far more efficient to describe what is known of its past history. We do not try to say where atoms are in an organism; instead we mention its species, age, etc. Organisms might be defined as systems whose future behaviour is more easily estimated from their past history than from what can be known about their immediate internal structure. The most convenient formulation of organic laws will therefore be expressed in terms of the age of the organism and take account of how its life has been spent. These laws are necessarily irreversible, since the assimilation of oxygen or food is always going on in a manner which can never be reversed. Life is like a function which must always alter in one direction; when this development ceases life has disappeared.

The contrast of living and dead now appears less important than the following classification of natural processes:

1. Processes which are reversible and whose laws can be expressed independently of the age of the system, e.g. gravitational and mechanical motions which do not involve light or heat.

2. Processes which are irreversible, the laws being best expressed in terms of the total time which has passed since some initial state, e.g. chemical combination, growth, evolution, radioactivity, and all changes involving light or heat.

Physics has always asserted that processes of the first type were fundamental in nature, and astronomy provided the ideal example in planetary motion. It was this assertion that gave rise to the essential issue behind the conflict of mechanism and vitalism. But if Born is right, and the fundamental atomic processes are irreversible, then the situation is completely altered. There is no longer a question of life being an arbitrary irruption in a world of mechanical law, since the laws of gravitation and mechanics must then be looked on as the limiting case, when the irreversibility is vanishingly small, of a whole series of irreversible processes which constitute the most important examples of the fundamental order in nature. This series would include the atomic processes connected with heat, light, and electricity, chemical combination, colloidal effects, organic growth and evolution, and the highly co-ordinated electrical processes which form the physiological basis of consciousness.

If this view is correct the atomic processes of radiation and chemical combination should be just what the biologist needs to build up organisms. Instead of a chaos of little particles obeying inverse square laws, the modern physicist offers to the biologist a new kind of atom with electrical and magnetic properties which cause it to build up stable compounds.

The biologist may reply: “Yes, but organisms have four chief characteristics, their behaviour is irreversible, and displays growth, memory, and purposiveness. If you tell me that your atoms obey irreversible laws, so much the better, because my organisms certainly do. But your crystals grow very differently from my cells and organisms, and you can’t explain away the apparent purposiveness of all life.”

To which the physicist may answer: “Suppose that two hydrogen atoms are some distance apart with the total energy necessary to make a molecule. If they begin to move towards one another under some attractive influence which they exert we display no surprise. But they are moving towards a final end, which is an end, even though they are of course unconscious of it; and provided that nothing interferes they will reach one another, form a molecule, and the process will be consummated. The atoms move under an irresistible law of attraction towards a final condition which is unavoidable unless outside influences prevent it. The system of the two atoms develops necessarily towards a consummation, and the process has in this sense a teleological quality, though this need not mean that any god or man had consciously planned the end for these particular hydrogen atoms.

“This quality was not present in Newton’s law of gravitation precisely because it failed to say what happens at the end of any process, for instance when a meteorite hits the earth. Newtonian laws avoid the responsibility of dealing with all the exciting events, like the wedding of the atoms or the death of the meteorite. On the other hand it appears probable that all irreversible laws can be interpreted as leading either from or to some critical end condition. Thus all heat processes tend towards an approximate uniformity of temperature, and chemical reactions also move towards a final condition.

“Such systems as these display the rudiments of unconscious purpose. One must imagine these systems made much more complex so that it takes a long time and considerable nourishment before their unconscious purpose is fulfilled, whether this be the instinctive reproduction of their kind or any other biological function.”

“Maybe. I like the unconscious purpose which you have revealed in irreversible physics, because I am troubled by colleagues who see conscious mind everywhere.

“But if I grant that your view of the atom, and hence of molecules and colloids, allows me two of the four features I find in life, i.e. irreversibility and unconscious purpose, you have still to deal with growth and organic memory.”

“Yes. Growth and memory are things that physics has as yet little to say about. But we have at any rate reduced the problem of life to smaller proportions. It is no longer the question what is life? but, how do colloidal processes build themselves up into continuously-active, developing systems which can react to their surroundings so that some distant condition can ultimately be attained? This is a much less difficult question. Moreover, since the problem of radiation underlies all the chemical processes which are associated with the maintenance of life, we may expect considerable assistance when physics has cleared up this crucial problem.”