My objective in this book is to show the living world and especially the animal world as part of yet distinct from the inanimate world and to consider particularly the animal world especially as it appears to approach the human world in behaviour and capabilities. Then I propose to consider man firstly as part of the animal world and secondly as in some respects uniquely different from the animals and to discuss the nature and extent of this uniqueness. I am only too aware of the immensity of this undertaking involving as it does incursions into many branches of science both physical and biological. And as if that were not enough I must attempt substantial raids into the territories of various branches of psychology philosophy linguistic and other arts and not least theology! Though parts of this book must inevitably be complex I have chosen a simple title Animal Nature and Human Nature. In this title I use the word “nature” in its ordinary everyday meaning as denoting the qualities of anything which make it what it is and this implies that we are trying to discover the essential quality character or disposition of the beings we talk about.
There are two key questions to be asked at the outset questions which are continually debated by scientists and to which the answers are very far from clear: Is there a real unbridgeable gap between (1) the living and the non-living and (2) between man and the rest of the living world?
Just because the relationship or lack of relationship between animals and men is central to my whole theme I have in choosing the examples of animal behaviour that I discuss often selected the more complex the “higher” or what appear to be the more “intelligent” instances. But I am anxious not to give the impression that all the animal world is like this; and so it is essential to start with an aspect of the whole subject which is more technical and difficult than most—that is the relations between the animate and the inanimate between the approaches of the physicist chemist and engineer on the one hand and the biologist naturalist and psychologist on the other.
Whenever we discuss the sciences and particularly how to teach them even when we just think about them most of us tend to place them in our minds in a linear series. Mathematics and physics are at the top and the others arranged down the rungs of a ladder up which they are proceeding as they become more exact. The so-called descriptive sciences are at the bottom of the ladder perhaps not even standing on it at all but still waiting for the first lucky throw as in a dice game (Pantin 1968). In fact a little thought shows that this linear arrangement is certainly wrong. We have only to consider astronomy geology and biophysics to see that much. The divisions we make are in fact arbitrary and the divisions between physical science and biological science at first appear as merely those of practical convenience. Obviously the sciences form a multidimensional network—some of them complex some of them apparently much simpler some of them highly precise and exact some with a lot of fluff round the edges.
The Relations Between the Sciences
A hundred years ago it was customary to divide sciences into the observational and the experimental (Pantin op. cit.). When we merely note and record phenomena which occur around us in the ordinary course of nature we are said “to observe.” When we change the course of nature by the intervention of our will and manipulative powers producing new or unusual combinations of phenomena we are said “to experiment.” Sir John Herschel suggested that these two modes would be better called passive and active observation. Obviously observations are made in both cases; experiment is therefore just observation plus the controlled alteration of conditions. There are of course “natural experiments” such as the occurrence of eclipses or the appearance of super nova stars; and the astronomer even today has to wait for the appropriate time or journey to the appropriate place in order to find the conditions most fitted to allow firmer conclusions to be drawn. In the mid-nineteenth century it was frequently said that geologists ought only to observe and not to theorise—in response to which argument Charles Darwin remarked that at this rate a man might as well go into a gravel pit and count the pebbles and describe their colours. He even went so far as to say and we should all agree with him today that even to be a good observer one must be an active theoriser.
But the physical scientists are unwilling to deal with any project where they cannot in at least some and often a very high degree manipulate the conditions. In doing this they are in fact abstracting from the richness and complexity of the natural world and focussing their attention on small parts of it—with the spectacular results that we all know today. Carl Pantin (1968) said that physics and chemistry had been enabled to become exact and mature just because so much of the wealth of natural phenomena is excluded from their study. So there is no need for the classical physicist or chemist as such to go to biology for data; he in fact restricts himself to certain types of material and situations which his techniques and theories can deal with and for this reason Pantin in fact following Clerk Maxwell (in 1877) calls such sciences “restricted.” In contrast biology and geology are “unrestricted.” Scientists devoted to these latter fields may have to follow the analysis of their problems into every other kind of science; whereas the physicist can stick to his last. This selection or restriction enables the physical scientist to make rapid progress with the help of mathematical models of high intellectual quality. To quote Carl Pantin again “Very clever men are answering the relatively easy questions of the Natural Examination Paper. Intellectually magnificent though the attack upon these problems has been the problems they present are easier than those of the unrestricted sciences of which biology is the obvious example.”
At first sight it might seem that the fact that sciences like geology deal with gross phenomena is an indication of immaturity. Similarly with psychology. Indeed during the last twenty-five years experimental psychologists have again and again pleaded that the reason why their results are not more satisfactory and firmly established is because their science as yet lacks an Isaac Newton. It should therefore so they argue be their aim to make psychology as precise and exact as physics. But it is an error to suppose that it is only micro-events such as the behaviour of electrons and of molecules which are worthy of the consideration of the true scientist. Indeed the astronomer and geologist would heartily agree with the biologist that there is much to be learned from the study of slow-acting systems of relatively large size; these systems simply cannot be examined with the precision and exactitude characteristic of the work of the chemist and physicist. Nonetheless it is and of course must be the aim of all branches of science to render themselves as exact as possible; and so as the various disciplines mature mathematics is brought more and more into the picture—even nowadays in such apparently unmathematical subjects as taxonomic botany. New mathematical techniques are continually being produced to answer questions which have become too intractable for the old-fashioned methods of observation and description. This is of course just as it should be and reveals another important point: namely that since mathematics is really the study of relations so also is science to a very large extent the study of relationships; and we may find important relations displayed in the interaction of species of animals at one level of size in the movements of strata and the drift of the continents at another level of size as well as in the unimaginable distances of the stellar universes. This does not mean that these sciences are simply becoming new branches of physics and chemistry! On the contrary they are revealing new features and new laws as they become more exact—features and laws which the chemist and physicist by themselves are powerless to investigate.
Knowledge of the “Objective” World
To say that science investigates relationships is of course only one aspect of the truth. The word science formerly meant the whole of knowledge; but by popular usage it has become more or less restricted to knowledge about objects in the natural world—that is the task of the natural sciences. This brings us to the next important question namely—what are the “objects” which the scientist investigates? Nature presents itself to us in one aspect as a continuum. In studying this continuum we recognise complexes of phenomena which retain identity and show a high degree of stability and persistence of pattern in contrast to examples with less cohesive features (Weiss 1969). In practice the scientist like everyone else accepts the reality of descriptions of the external world as in some sense made up of “real” objects. We may all be confused at the first sight of an entirely new object or of an old object in an unfamiliar situation. A curved stick in the forest may look like a snake a toadstool may look like a delightfully sticky bun and we have to look quite carefully before we can decide what it is we are really seeing. At first glance we may be quite certain of our identification only to find perhaps to our embarrassment how wrong we have been. A favourite dog of mine who was fond of chasing cats was not prepared for the fact that a neighbour had acquired a highly miniaturised Yorkshire Terrier which at a distance looked to her like a cat. She chased it and her confusion when it turned and barked at her was comical to behold.
As scientists we must beware of following the psychologists of a previous generation and looking upon sense data as a substance “out of which we build perceptions.” Rather sense data are highly intellectual abstractions from it robbed of those relationships which are the basis of our conviction of reality. But above all the scientist whatever he may say always believes that he is investigating a real world consisting of “objects” whose relationships he can study. Now the most striking feature of the everyday world of objects is the enduring character of the things in it. Apart from cyclical changes daily and seasonal the world is full of things which we see as objects; some of them like the hills and the oceans are constant over immense periods of time; others like snowflakes and lightning flashes and many radio-active atoms and elementary particles may have very brief even infinitesimal existences. So the “real world” is built up of objects that endure though (with the exception of certain primary physical particles) decaying slowly or rapidly and other objects displaying dynamic equilibria (as does our atmosphere) which may endure for an immense period of time. And indeed most of the objects which as biologists we study are in a state of dynamic equilibrium. For though both a man and a mollusc may be presented to our senses as a continuing individual for a long time the tissues of which they are composed are for the most part in a continual state of flux; like a river whose form may remain substantially constant even though the water is continually changing they can be composed of an entirely different set of molecules after the lapse of a few years. So our choice as to what we call “objects” obviously depends on our senses and on the fact that these senses only cover a certain range; our perceptions are in fact limited by what may be called our “sensory spectrum.” We only see with light over a certain range of wavelengths. Bees have a good colour sense but it corresponds to quite different divisions of the visible spectrum from our own and includes a region of sensitivity in ultraviolet. It is difficult for us to imagine what the bee is “seeing” when it can be trained to respond differentially to two white papers that are to our vision identical but one of which reflects ultraviolet and the other does not. Again with our unaided senses we do not perceive things which are too small or too vast or which endure for too short a time. The endurance of an enduring object is to be measured against the time scale of our own lives and senses. Events which are too small too large too quick or too slow are not perceived and unless our attention is drawn to them by indirect means we know nothing about them.
The Approach of the Physicist
But while we must have objects to study and “facts” about them—nevertheless in all branches of science we find that as we analyse so the facts and objects tend to disappear and become systems of relations. It has always been so and very disturbing it is too. Scientists have at times been moved by a robust sense of a reality waiting to be studied of nature as bringing to them an intelligible message which they only have to decipher (Toulmin 1966). Yet at other times the programme of science has been modified so fast as to leave many almost in a state of shock. The popular and semi-popular writings of Eddington in the 1930s played a great part in helping the ordinary man to understand what was going on as the safe material world of Victorian physicists seemed to be dissolving under his very eyes. This is no new problem. Some deplore change some welcome it; and the changes that have taken place in theoretical science may indeed be welcomed even though they may seem to conflict with common sense since by and large they undoubtedly constitute immense advances in our understanding of the very nature of the natural world. But we always feel some pangs for the disappearance of the worlds we knew just as did Newton and Galileo in their last years a feeling which was well expressed by John Donne in 1611 who wrote
And new Philosophy calls all in doubt
The Element of fire is quite put out;
The Sun is lost and th'earth and no man's wit
Can well direct him where to looke for it.
And freely men confesse that this world's spent
When in the Planets and in the Firmament
They seeke so many new; then see that this
Is crumbled out againe to his Atomies.
‘Tis all in peeces all cohaerence gone;
All just supply and all Relation.1
Ever since Victorian times it has been the changes in physics and in astronomy which have in fact seemed so appalling and disconcerting to many thoughtful men. Many of our most cherished beliefs have gone by the board. Atoms were thought to be permanent unchanging elements of nature. Now far from remaining unaltered they appear to be created destroyed and transmuted. What do remain enduring are certain abstract attributes of particles of which the electric charge and the wave aspects of elementary physical particles are the most familiar. Edmund Whittaker (1949) has described what he calls postulates of impotence but which Bronowski (1969) has cleverly entitled the laws of the impossible a break-up of which is particularly disturbing. Thus a great part of mechanics can be derived from the single assertion that perpetual motion is impossible. A great part of electro-magnetism follows from the assertion that it is impossible to induce an electric field inside a hollow conductor. Again in special relativity it is impossible to detect one's motion if it is steady even by measuring the speed of light. In general relativity it is impossible to tell a gravitational field from a field set up by one's own motion. In quantum physics there are several laws of the impossible which are not quite equivalent: the principle of uncertainty is one another is that it is impossible to identify the same electron in successive observations. At bottom all the quantum principles assert that there are no devices by which we can wholly control what state of a system we will observe next: Bronowski translates that into the statement “It is impossible to ensure that we shall copy a specified object perfectly.” And this disturbing process of change seems to be accelerating till one wonders how it will end if end it will! As J. B. S. Haldane once said (not long before his death) “My own suspicion is that the universe is not only queerer than we suppose but queerer than we can suppose.”
Indeed the inevitable conclusion from quantum theory seems to be that nature is fundamentally non-mechanical. Some experts go so far as to suggest on the basis of their knowledge of quantum theory and its effectiveness that it is better (that is to say more rational) to start by being indeterministic in general (Linney and Von Weizsäcker 1971). Von Weizsäcker suggests that belief in quantum theory is similar to the belief that nature is indeterministic. But of course one must not suggest that quantum theory in its present form is final. Indeed at the present time there are strong criticisms of it coming from philosophers and philosophically minded physicists. This tendency is based upon the conviction that ideas like complementarity correspondence uncertainty and indeterminacy have always been indefensible on philosophical grounds. Therefore such physicists all propose the idea that there must be hidden variables in quantum theories and so they proceed to indulge in perfectly respectable and allowable speculation as to what is needed beyond quantum theory to provide a satisfactory philosophical picture. Of course speculation is essential in research as it is in any field of thought which is not fixed by rigid dogma. Theoretical physicists are an exceptionally able and intelligent group. Indeed they exemplify the dictum that an intelligent man is one who can hold two contradictory concepts in his mind simultaneously. The trouble however is that speculation no matter how rational and revealing it may seem is not an alternative to a working theory however imperfect that theory may be. It must be said that the physicists who stick to quantum theory find that it is still an indispensable tool in research. That is to say it turns out results expressible in numerical terms. So far the speculations aimed at refining or replacing quantum theory have not produced results in this way and until they do they are hardly likely to emerge victorious.
One of the most striking differences between physics and biology arises in just this context. I think one can say that in biology there are no genuinely biological postulates of impotence except that spontaneous generation is impossible. Any other postulates of impotence which may appear to be part of biology are in the end I think reducible to physics and it is from that discipline they really come.
But there is another side to all this. There are assumptions which we cannot do without even though all seems to be dissolving. One of these is that there is a real world which we in some measure apprehend by our senses: that is to say that knowledge is possible. And (as Bronowski 1969 points out) in the field of science this means that it is rational. But this is not to imply that nature is necessarily therefore all machine-like. And this idea of a great machine is one of the great misconceptions of our age haunting the biologist now as it haunted the thinkers of the nineteenth century when Tennyson wrote “The stars she whispers blindly run.” But let us come back to biology and particularly to the ideas of modern biology as affecting man's views of nature and his own place in it.
Thunderstorms and Organisms Compared
In 1944 Professor Schrödinger wrote a little book entitled What Is Life? This treatise of less than a hundred small pages has perhaps had more influence on recent thinking on this topic among both physicists and biologists than almost any other recent study. Schrödinger points out that when a piece of matter is said to be alive it is because it goes on “doing something”—moving exchanging material with its environment and so on. Moreover it goes on doing this for a much longer period than we would expect an inanimate piece of matter to “keep going” under similar circumstances. A system that is not alive if isolated or placed in a uniform environment usually ceases all motion very quickly as a result of various kinds of friction. Temperature becomes uniform by heat conduction and after that the whole system fades away into a dead inert “lump of matter.” A permanent state has been reached in which no macroscopically observable events occur a state which the physicists speak of as thermodynamical equilibrium or “maximum entropy.” During a continued stretch of existence it is by avoiding rapid decay into the inert state of equilibrium that an organism appears so enigmatic; so much so that from the earliest stages of human thought some special non-physical or supernatural force was claimed to be operative in the organism.
Pantin in discussing such statements points out that almost everything that Schrödinger has said about life could at least in some measure be said about a thunderstorm. A thunderstorm goes on doing something moving exchanging material with the environment and so forth; and that for a much longer period than we would expect of an inanimate system of comparable size and complexity. It is by avoiding the rapid decay into an inert system of equilibrium that a thunderstorm appears so extraordinary. But the parallels between living organisms and thunderstorms and indeed some other meteorological phenomena are remarkable. It is true that thunderstorms arise by spontaneous generation and since they are incapable of sexual reproduction natural selection can only act upon them by selecting individuals and not by acting upon the whole species. Like living organisms they require matter and energy for their maintenance. This is supplied by the situation of a cold airstream overlying warm moist air. This situation is unstable and at a number of places vertical up-currents occur. Once these have developed they are maintained at least for a while through the liberation of heat consequent upon the formation of rain as the warm damp air rises. Each up-current “feeds” upon the warm and damp air in its neighbourhood and is thus in competition with and can suppress its neighbours. A storm is in fact parasitic on the increase of entropy which would result from the mixing of warm moist and cold air to form a uniform mass. Moreover the storm itself has a well-defined anatomy of what can almost be called functional parts. The two accompanying (Figures 1 and 2) illustrations show this better than would a long detailed description. But although certain non-living systems of which the thunderstorm is such a striking example do show what we can call “organismal characters.” This property is nowhere found in so high a degree as it is in living organisms.
Woodger (1960) pointed to the importance of the fact that living things have parts which stand in a relation of existential dependence to one another—e.g. limbs digestive organs circulatory systems and brains. And even in a single cell (Figure 3) we find organelles so to speak micro-organs all of which seem to constitute some essential part of the cell's machinery. So we can ask of the structures in a living organism just as we can ask of the structures in a man-made machine what is this for? We can often give fairly exact and plausible answers. It has been argued I think convincingly that we cannot sensibly ask that kind of question of natural non-living systems. It is surely nonsense to ask of a solar system or its parts or of a nebula or an atomic structure or of the parts of a mineral “What is this for?” Any answer which we think we can give is an answer of an entirely different kind from that which we can give in the case of a man-made machine or the parts of a living organism. Another distinction of course concerns reproduction. If we compare this in living and non-living systems we find that in non-living systems (e.g. thunderstorms or vortex rings) new examples are generated but the new ones do not exactly reduplicate the old. In the reproduction of living organisms however reproduction is essentially reduplication of all the essential features of the design (Pantin 1968). It is the fact that the organisation of living creatures whether great or small is determined by a molecular and therefore precisely repeatable template that makes biological reproduction possible. So we can say (a) what organisms do is different from what happens to stones. (b) The parts of organisms are functional and are interrelated one with another to form a system which is working in a particular way or appears to be designed for a particular direction of activity. In other words the system is directive or if we like to use the word in a very wide and loose sense “purposive.” (c) The material substances of organisms on the one hand and inorganic materials on the other are in general very different. And there is still another difference (d) which seems to me of great importance and that is that organisms absorb and store information change their behaviour as a result of that information and all but the very lowest forms of animals (and perhaps these too) have special organs for detecting sorting and organising this information—namely the sense organs and specialised parts of the central nervous system. I shall return to this very important aspect later.
First we must make it clear as of course Michael Polanyi (1967) has done that we adhere to the basic assumption that all local structural or physiological organisations and events inside the living being occur according to a local biochemical determinism. That is to say that there is no firm evidence whatever against and an immense amount of evidence for the view that the “ordinary” laws of physics and chemistry are holding within the organism just as they do within a man-made machine. The problem is how to explain the stability and reproduction of even the simplest organism in space and time in terms of the organisation of the structure itself.
The Approach of the Biologist
It is a claim of molecular biologists a claim with which we can in general agree that they have made very large steps towards reducing the problem of the organisation of the living being (including even the problem of its hereditary processes) to physical laws. Some indeed would claim to have accomplished the whole task already. We shall come back to the question of the hereditary organisation later. Here we can say that what has been done by the molecular biologists is to develop a model of the cell which behaves very much like a classical man-made machine or an automaton but one in which the “secret of heredity” is found in the normal chemistry of nucleic acids and enzymes. The implication of this is that parts functioning like a machine can be described as a machine even though these parts may be single molecules; and machines are understood in terms of elementary physical laws. This is an attractive analogy and is indeed one which we have all been using for a long time. As has been explained above we repeatedly and successfully ask the question “What is this for?” when considering the different structures in living organisms—quite as successfully and legitimately as we can ask this of a piston a lever or an electric circuit in any machine designed by man.
The Nature of the Organisation Shown by Living Beings
But we can easily be trapped by this useful analogy into losing sight of two basic aspects of living beings which are clearly evident to the physicist but curiously enough overlooked by the biologist. It is of course no satisfactory answer to respond to the question “How does a man-made machine or living machine work?” by saying that it obeys the laws of physics and chemistry. As Pattee (1971) points out if we ask “What is the secret of a computing machine?” no physicist would consider it in any sense an answer to say what he already knows perfectly well that the computer obeys all the laws of mechanics and electricity. If there is any problem in the organisation of a computer it is the unlikely constraints which so to speak harness these laws to perform highly specific and directive functions which have of course been built into the machine by the expertise of the designer. So of course the real problem of life is not that all the structures and molecules in the cell appear to comply with the known laws of physics and chemistry. The real mystery is the origin of the highly improbable constraints which harness these laws to fulfil particular functions. This is in fact the problem of hierarchical control. And any claim that life has been reduced to physics and chemistry must in these days if it is to carry conviction be accompanied by an account of the dynamics and statistics and the operating reliability of enzymes ultimately in terms of present-day groundwork of physics namely quantum mechanical concepts. So we have two questions “How does it work?” and “How does it arise?” The second question has in fact two facets: (a) how does it arise in the development of the individual organism during the process of growth from the moment of fertilisation of the egg and (b) how does the egg itself come to get that way; that is to say how can we conceive of evolution as having “designed” the cell?
The Idea of Hierarchy
It is the necessary concept of hierarchy in biology which pinpoints the problem. And the problem is one of hierarchical interfaces. In common language a hierarchy is an organisation of individuals with levels of authority—usually with one level subordinate to the next one above and ruling over the next one below. For an admirable account of this see Koestler and Smythies (1969). So any general theory of biology (which must include the concept of hierarchy) must thereby explain the origin and operation the reliability and persistence of these constraints which harness matter to perform coherent functions according to a hierarchical plan. Pattee (1970 1971) says
it is the central problem of the origin of life when aggregations of matter obeying only elementary physical laws first began to constrain individual molecules to a functional collective behaviour. It is the central problem of development where collections of cells control the growth or genetic expression of individual cells. It is the central problem of biological evolution in which groups of cells form larger and larger organizations by generating hierarchical constraints on subgroups. It is the central problem of the brain where there appears to be an unlimited possibility for new hierarchical levels of description. These are all problems of hierarchical organization. Theoretical biology must face this problem as fundamental since hierarchical control is the essential and distinguishing characteristic of life (1970 p. 120).
He goes on to point out that a simpler set of descriptions at each level will not suffice. Biology must include a theory of the levels themselves.
I have said above that even the simplest biological mechanism is to a superlative degree more complex than the most complex of humanly constructed machines. It is perhaps instructive to consider this complexity as it appears when we look at the human body and brain. Professor Paul Weiss (1969) has put this very dramatically by pointing out that the average cell in our bodies contains about 105 macromolecules. The brain alone contains 1010 cells hence about 1015 macromolecules. To get these figures themselves into perspective it is worth remembering that the age of the galaxy in which our solar system resides is estimated at 1015 sec! This is to say each of us has in our brains about as many cells as there have been seconds since our part of the cosmos began to assume its present form. Paul Weiss says:
Could you actually believe that such an astronomical number of elements shuffled around as we have demonstrated them to be in our study of cells could ever guarantee to you your sense of identity and constancy in life without this constancy being insured by a superordinated principle of integration? Well if you could for instance by invoking a “micro-precisely” predetermined universe the following consideration should dispel that notion. Each nerve cell in the brain receives an average of 104 connections from other brain cells and in addition recent studies on the turnover of the molecular population within a given nerve cell have indicated that although the cells themselves retain their individuality their macromolecular contingent is renewed about 104 times in a lifetime. In short every cell of our brain actually harbours and has to deal with approximately 109 macromolecules during its life. But even that is not all. It is reported that the brain loses on the average 103 cells per day irretrievably rather at random so that the brain-cell population is decimated during the life span by about 107 cells expunging 1011 conducting cross-linkages. And yet despite that ceaseless change of detail in that vast population of elements our basic patterns of behaviour our memories our sense of integral existence as an individual have retained throughout their unitary continuity of pattern (p. 13).
This is just another way of putting the problem that Schrödinger poses in his book What Is Life? The problem is mainly that of the contrast between the degree of potential freedom on the one hand and on the other hand the perseverance and the essentially invariant pattern of the functions of such systems. (By “degrees of freedom” we mean simply the number of variables necessary to describe or predict what is going on. Thus there is a potential freedom amongst trillions of molecules making up the brain or for that matter the whole body.)
Consider this for our nervous system and following this our thoughts our ideas our memories. Schrödinger was forced to the conclusion that as he put it “I … that is to say every conscious mind that has ever said or felt I … am the person if any who controls ‘the motion of the atoms’ according to the laws of nature.” This puts the problem of the boundary conditions which have to be maintained all the time in both simple and complex examples of biological mechanisms as it appeared to one of the most able physicists of his time who had given particular thought to these problems. Polanyi as we have seen assumes that all molecules work according to natural laws but concludes that since no one has accounted for hierarchical organisation by these laws there must be principles of organisation which will in due course be found not to be reducible to the laws of physics and chemistry. Many others would be rather more cautious. Thus the physicist Pattee (1970) expresses himself as neither satisfied with the claim that physics explains how life works nor the claim that physics cannot explain how life arose. In his view (I) the concept of autonomous hierarchy involves collections of elements which are responsible for producing their own rules as contrasted with collections which are designed by an external authority to have hierarchical behaviour. He then (II) assumes of course that they are part of the physical world and that all the elements obey the laws of physics. He limits his definition of hierarchical control (III) to those rules or constraints which arise within such a collection of elements but which affect individual elements of the collection. Finally and perhaps most important he points out (IV) that collective restraints which affect individual elements always appear to produce some integrated function of the collection. In common language this is to say that such hierarchical constraints produce specific actions or are “designed for” some purpose.
It is in considering the third of the above four statements in relation to classical mechanics that the difficulties are seen to be at their greatest. Classical physics appears to provide no way in which an explanation can be reached because it requires a “collection” of particles which constrains individual particles in a manner not deducible from their individual behaviour. However it has been pointed out that in quantum mechanics the concept of the particle is changed and the fundamental idea of a continuous wave description of motion produces the stationary state or local time-independent collection of atoms and molecules. So it seems to be not impossible that hierarchical structures could be reducible to quantum mechanics although as we shall see later the whole scheme of quantum mechanics is now in such confusion that to the outsider it seems far from clear to what extent they will be able to help. But even if structural hierarchies can be explained ultimately in this way there is still something missing when we come to biological systems. Complexities of physical structure seldom if ever by themselves provide any feature which seriously suggests to biologists that such structures are in any sense alive. As has been said above what organisms do is different to what happens to stones. The piece missing in the hierarchies of the non-biological world is once again function. What is so exceptional about enzymes and what creates their hierarchical significance is the simplicity of their collective function which results from their very detailed complexity. This is the core of what is meant by integrated behaviour.
We are generally content with the view that a physical system at least a macrophysical system may appear completely deterministic; but the attempt to reduce living systems to such that is to say formal reductionism fails in part because the number of possible combinations or classifications is generally immensely larger than the number of degrees of freedom. And then as we have seen and as we shall see more clearly later living systems are self-programming; this means that the particles of which they are composed form an internal simplification or self-representation; and these systems of self-representation which assume control of the whole seem utterly baffling in many cases because they appear to originate spontaneously. Again this means that the organism is self-programming. This concept of living organisms being uniquely different from non-living systems in having internal self-representation raises a point of most profound importance. As will be argued later in this book it is difficult to know if and where in the animal kingdom one has the need to postulate “self-consciousness” “self-awareness” or to use Eccles' phrase “the experiencing self.” We come to the conclusion that as we proceed from man downwards through the animal series the lower we go the less useful (as predictive of animal behaviour and as leading to an understanding of animal nature) the concept becomes. Until with the lowest animals and with the plants the usefulness of the idea becomes vanishingly small. But if it be true that all living organisms have internal self-representation does this not amount to saying that the seeds of self-consciousness are present in all living creatures—from the virus and the bacterium upwards?!
Another theoretical physicist Walter M. Elsasser (1966) has approached some of these problems in an original manner by considering the number of internal configurations in which a complex system may exist in theory. Astronomers assume the existing finite total of atomic nuclei is of the order 1080 but as we have seen the lifetime of our galaxy is assumed to be no more than 1018 sec. Elsasser (1966) argues that the number of distinguishable events which can occur in a finite universe is correspondingly limited. In considering these systems of increasing complexity we must soon reach a point where a number of internal configurations in which the system may exist will vastly exceed the number of actual examples of any one given class that can possibly be collected in our universe. It follows that if the discrepancy between the number of possible states and the number of possible samples is large enough we can assert without fear of contradiction that no two members of a class e.g. no two members of an animal or plant species not even two bacteria can ever be in the same internal state. This leads Elsasser to suggest another characteristic of living organisms as distinct from non-living. He says that in physics the classes of things e.g. atoms protons electrons etc. are very homogeneous. It is a fundamental assumption that all the helium atoms in the universe are identical; though when we come to larger aggregations however fully homogeneous the class the objects would have to be not only chemically equivalent but also in the same quantum state. That is to say for complete homogeneity all the members of a class have to be at the absolute zero point of the temperature scale so that their molecules are in the ground state. But the point is that in principle we do have and can work with the idea of homogeneous classes in physics. And all fundamental questions of theory may be evaluated in terms of these. This can never be the case in biology even in principle as the number of individuals in any class in existence at one time is far too small to allow statistical prediction to have any physical significance. The resulting conclusion is that while physics is a science dealing with essentially homogeneous systems and classes biology is a science of inhomogeneous systems and classes. In physical terms one may say that an organism must be a system that is endlessly engaged in producing regenerating or increasing inhomogeneity and thereby the phenomenon of individuality at all levels of its functioning.
Polanyi seems so convinced of the impossibility of the physical explanation of these biological constraints that he often appears to be speaking as a vitalist. That is to say he is coming near to returning to the original idea of indwelling vital principle guiding the organism in some manner completely independent of its physical nature. Elsasser does not go as far as this and he suggests that there is room for (and we must assume the existence of) separate laws—biotonic laws as he calls them—which are compatible with the quantum laws but not deducible in principle from them. Two other physicists have considered this matter carefully (E. H. Kerner in Waddington 1970 and D. Bohm in Bastin 1971). Bohm indeed appears to find not only room for but even within physics itself a necessity for “hidden variables” which the usual scheme of quantum theory has ruled out as a matter of principle. Kerner considering this hesitates as yet to espouse either biotonic law or the incompleteness of quantal law for he feels that no clear set of observations seem thus far to compel either. And we must not forget that a quantum-mechanical calculation even on one particular bacterial cell would be incorrect for every other cell even of the same species—a point clearly made by Elsasser in his conclusions about the heterogeneity of the material with which the biologist has to deal. Finally one must here bring in again the most important biological discovery of recent years and this is the discovery that the processes of life are directed by programmes. And not only directed by programmes and not only manifesting activity but in some extraordinary way producing their own programmes. Professor Longuet-Higgins (in Waddington 1970) sums this up from the biological point of view by showing that it results in the biological concept of the programme being something different from the purely physical idea of the programme; and we can now point to an actual programme tape in the heart of the cell namely the DNA molecule. Even more remarkable is that programmed activity which we find in living nature will not merely determine the way in which the organism reacts to its environment; it actually controls the structure of the organism and its replication including the replication of the programmes themselves. This is what we mean by saying once again (a statement that can hardly be reiterated too often) that life is not merely programmed activity but self-programmed activity.
Monod (1971) has suggested that the combination of processes which must have occurred to produce life from inanimate matter is so extremely improbable that its occurrence may indeed have been a unique event (an event of zero probability). Monod also rightly points out that the uniqueness of the genetic code could be the result of natural selection. But even if we assume this the extraordinary problem remains that the genetic code is without any biological function unless and until it is translated that is unless it leads to the synthesis of the proteins whose structure is laid down by the code. Now Monod shows that the machinery by which the cell (or at least the non-primitive cell which is the only one we know) translates the codes “consists of at least fifty macromolecular components which are themselves coded in DNA.” Thus the code cannot be translated except by using certain products of its translation. As Sir Karl Popper (1972) comments “this constitutes a really baffling circle: a vicious circle it seems for any attempt to form a model or a theory of the genesis of the genetic code.” In fact this undreamed of breakthrough of molecular biology far from solving the problem of the origin of life has made it in Sir Karl Popper's opinion a greater riddle than it was before. Thus we may be faced with a possibility that the origin of life like the origin of the universe becomes an impenetrable barrier to science and a block which resists all attempts to reduce biology to chemistry and physics. So difficult does it now seem to suppose that this earth can have supplied the necessary conditions for long enough to allow even a reasonable probability of the origin of life here that Crick and Orgel (1973) have been carefully and seriously considering the possibility that some simple form or forms of life may have been deliberately transmitted to this planet by intelligent beings on another!
The Concepts of Information
I have already used the terms “communication” and “information” and shall do so more as we proceed. And already we see that a recording and a read-out of information are both ideas fundamental to the concept of “life.” So from the behavioural point of view it is very important to get our minds clear as to what we mean by communication. Here and in what follows I shall try to use the term “communication” only in the sense of interactions between organisms. This is different from the use of communication by many communication engineers who use it loosely to mean the transmision of information regardless of its origin or destination. They will happily speak of a rock or a hillside as communicating with an observer if some light reflected from the rock reaches his eyes. Worse still as Donald MacKay has pointed out the engineer's definition of a communication channel does not even require a causal connexion between the two points in question! Provided that the sequence of events at A shows some degree of correlation with the sequence at B authors are ready to define a channel capacity “between A and B” regardless of the possibility that the correlation is due to a third common cause and not after all to any interaction. So in their sense communications between A and B may imply (a) correlation between events at A and B; (b) causal interaction between A and B; (c) transmission of information between A and B regardless of the presence of a sender or recipient and/or finally (d) a transaction between organisms A and B.
MacKay (1972) gives a delightful example. If we see a man walking in the street carrying sandwich boards can we legitimately say that he is communicating a message to all who see the sandwich boards? Surely not! The man may have his eyes on the ground and not see most of the people who look at the boards. Some people may be foreigners who cannot read the boards and the man himself may be unable to read! On the other hand most people when they speak (or if they signal by Morse code) are directing their signals to some individual known or unknown with the expectation that communication will be established. It seems then that it is best to restrict the term “communication” to the sense in which a person or animal A communicates with a person or animal B only when A's action is goal-directed towards B. When I say “goal-directed” I mean either programmed by heredity or experience to be appropriate to perception by B or to be deliberately emitted in order to affect B or individuals of a similar class or type. If this relationship between A and B does not exist then it is better simply to say that B perceives this or that about A or that “information flows” from A to B.
There is another criterion relevant to the attempt to define a living organism—namely that the organism is primarily something which perceives. And in saying this we mean that an organism (however simple and primitive it may be) in some sense searches for information and has some means of organising and storing its perceptions. This conclusion has been reached independently by a number of different workers as for instance by Agar (1943) an investigator with a wide zoological and philosophical knowledge and having especial experience of the zoologically lower animals namely the invertebrates. It was espoused also by Woodworth (1938) a comparative psychologist of broad outlook and wide experience who was too well informed to consider as did many of his psychological colleagues rats as “lower animals.” (See Thorpe 1963.) I do not propose in this context to discuss the very simplest organisms of all such as viruses and bacteria. But when we come to the protozoa and then to the somewhat high invertebrate animals it is very instructive to consider perceptual abilities and in what sense if any communication is taking place.
Perception and Learning in Organisms
Information storage must be occurring in some form or another in all organisms which show a predictable change of behaviour as a result of the impact of environmental conditions encountered by the individual—provided of course that this change in behaviour is not a mere loss of information resulting from traumatic injury. A change of behaviour as a result of individual experience comes very near to the most general definition of learning which has been put forward. I myself in order to rule out the effect of injury included in my first definition of learning the word “adaptive”; and by this I meant adaptive to the conditions of life of the organism over a considerable period of time. However an objection can be raised to this in that it includes as learning a great deal of homeostatic or self-regulative response of the non-sensory systems the result of say the direct effect of temperature light chemical stimuli especially hormones etc. on the animal body. This is not what is usually meant by learning and to avoid this diffculty I now define learning as “adaptive change in behaviour as a result of individual sensory experience.” This does leave a difficulty in that as in the lower organisms where there are no certainly identified special sense organs it is difficult and sometimes impossible to tell what is sensory and what is not. However by sensory I intend to imply a process of co-ordinating and structuring sense experience in some sort of systematic way in short what in a higher organism we should call perceptual learning—an organisation of what the psychologists used to call “raw sense data” into a systematic organised unit of information upon which behaviour can subsequently be based. This of course is a kind of process which is continuing unceasingly in all of us as we build up a perceptual world by the use of our eyes ears and other sensory systems. I shall have a good deal more to say about this later in respect of higher animals and in man. But I think for the immediate problem of our understanding of the storage and use of information it is best to consider how far animals can learn. So in the next chapter we shall commence with the most primitive animals such as the protozoa sea anemones and their relatives; then proceeding to the slightly higher type of organism namely the harmless necessary flatworm about which so much ink has been spilled both in professional journals and in the newspapers in recent times.