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Chapter 2 Order and Life
37
ORDER AND LIFE
INTRODUCTION AND SUMMARY In this and the next chapter I shall deal with some of the basic concepts of systems-theory when applied to living systems and to the general character of their organization. Since this is likely to be familiar ground for only a minority of readers, I shall d o SO into considerable detail. Most of this turns on the requirements of systems-theory to work only with concepts which can be accurately defined on the observable variables and assumed parameters of the systems under consideration. This covers more than just variables relating to their outward behaviour. It includes any variable whose value can in principle be determined by scientific means, internal variables as well as surface variables. Certain features of the activities of living systems will here attract our main attention, especially the directiveness which I discussed briefly in Section 1.7. When we come to describe certain states and activities in the brain which will prove to be relevant to our enquiry, we shall be characterizing some of these activities as appropriately related to the circumstances in which they occur; others will be described as adaptive; again others as coordinated, or as serving some particularfinction. All of these concepts relate to manifestations of that directiveness. We shall also be talking about states of readiness of the brain for some particular events, and about a subcategory of this which will be called states of expectancy. And for the purpose of our analysis we shall need a clear perception of what exactly is meant on all of these occasions and what each of the concepts implies by way of spatio-temporal and in particular, causal relationships. This conceptual clarity is also important if we are to relate our findings to the structure of brain functions in a manner that can be accurately formulated.
Ch.2 - Order and life.
38
Even so, the reader whose main interest lies in the conclusions we shall reach and in the postulates on which they rest, may omit these two chapters at a first reading, refemng back to them only when the need arises.
*** 2.1
- THE DIRECTIVENESS OF VITAL ACTIVITIES
Human beings are living organisms and living organisms are physical systems in the sense in which this term is now generally understood. But they are physical systems of peculiar kind. For, superimposed on the kind of orderliness that we can also find in nonliving systems, e.g. the orderly arrangement of atoms in a molecule or crystal, living systems have another kind of orderliness which we call their organization. It manifests itself in processes which we describe in such terms as regulation, control, adaptation, coordination, integration, and function. Consciousness is one of the most sophisticated manifestations of this organization, and if we want to understand consciousness in its full biological context, it is imperative to start with a clear idea of the distinctive type of orderliness which characterizes this organization, e.g. a clear idea of the general pattern of causal relationships on which it depends. We need this clear idea not only to be able to give precise physical definitions to the many (in general use still fuzzy) biological concepts which relate to it, but also to get a better perception of the general nature of the organic order in which the life of all human beings is embedded, and of the kind of harmony that it appears to produce within its sphere. For in the final chapters of this book I shall relate some aspects of the human psyche to the nature of this harmony and man's intuitive awareness of it. At the most general level, this organic orderliness manifests itselfin one of the most distinctive characteristics of living organisms, viz., the directiveness or goal-directedness of their activities or processes. Whatever you see happening in the living world, especially in the higher orders of life, generally seems to be directed towards the production of some biologically significant end-result: the organism crawls, runs, swims, or flies to get from A to B; it gathers food to fuel its energies; it hides to escape detection; it fights to protect its temtory; it burrows or builds a nest for shelter, it finds a mate in order to reproduce, and so on. Meanwhile its body performs a multitude of internal regulations to safeguard the constancy of the internal environment and to keep itself going as an effectively operating survival machine. In each case the actions or processes in question are seen to be directed towards the achievement of that end-result in the manifest sense that they are seen to be produced or controlled in such a way that over a variety of circumstances they will match those circumstances in a manner conducive to the end-result in question. If the mouse jumps to the left so will the cat.
2 2 - Dynamic versus structural order
39
This directiveness characterizes not only the behavioural responses and physiological reactions of the living organism, but also the much slower processes of ontogenetic development, maturation and learning. In a slightly more restricted sense, it characterizes also the long-drawn-out processes of evolution. For here, too, we see developments taking place which are able to match changes in the ecological conditions in a manner that is conducive to some biologically significant end-result. This, and no more than this, is what I shall mean by the teleological character of vital activities, while by teleological terms or concepts I shall mean all terms or concepts that relate to this directiveness or aspects of it. Many modem artefacts also achieve such directive behaviour, notably artefacts governed by servomechanisms incorporating negative feedback loops. The autopilots of ships and aircraft are typical examples. So are industrial robots and homing missiles. However, we cannot use the concept of feedback loop itself to characterize in objective and sufficiently general terms the nature of directive activities as such. To that end we need a characterization of what is achieved by such mechanisms, not an account of how it is achieved. And a more abstract analysis is required for that purpose. (Readers who are unfamiliar with the notion of 'feedback loop' will find the feedback system of a simple servomechanism illustrated in Fig. 3.1). It will be clear from the above remarks that the 'goal- directedness' of organic activities which I have described, is here viewed as an objective characteristic of the activities concerned, a characteristic which they share with the flight of a homing missile, for example. Unfortunately, such activities are also often described as 'purposeful' or 'purposive', and these terms have obvious mental connotations. They suggest the intervention of a mind motivated by conscious aims. It is important, therefore, not to confuse our objective sense of goal-dmctedness with this subjective or mental sense or purposiveness. The goal-directedness we are talking about does not imply the intervention of a mind at all. Moreover, although rational mental activity may well be regarded as nature's most sophisticated way of producing activities which are also goaldirected in an objective sense, it is not an infallible way. A human action may well be a purposeful one in the above subjective sense without satisfying also the criteria of goaldirectedness in the objective sense I have described. One can have a defmite goal in mind and yet do all the wrongs things.
***
2.2
- DYNAMIC
VERSUS STRUCTURAL ORDER
The story of life can be told at several distinct levels. One of these is the molecular and cellular level. This is the story of the macromolecules of which living cells and tissues are constructed: the story of DNA, RNA, genes, chromosomes, enzymes, and so on. The type of order that comes into focus at this level is mainly a geomemcal, three-dimensional
40
Ch.2 - Order and life
order: the orderly arrangement of atoms in molecules and of molecules in paracrystals, cellular membranes, tissue fibres, and other structures. It is a type of order which can be quantified in terms of negative entropy, because the thermo-statistical concept of entropy itself is a measure of the disorder that exists in a physical system at any given point of time. All the most spectacular advances of biology in this century have been made at this, the molecular level. But this is not the only level at which the story of life can be told. Inanimate objects are wholly at the mercy of their environment. The extent to which they can resist disruptive forces depends solely on the depth of the potential energy minimum which their physical structure occupies. Any physical force strong enough to lift it out of that minimum and over the surrounding 'energy humps' will prove disruptive. However, with the arrival of life, a new factor appeared on the scene, capable of ensuring endurance in the face of adverse environmental contingencies: systems appeared which had the capacity over long periods of time (spanning many generations) to undergo adaptive changes - that is, changes which were related to the characteristics of the environment in a way that increased the probability of survival. In due course a further improvement occurred: these slow evolutionary changes resulted in the development of mechanisms which could pick up information about the current state of the environment and produce behaviours which could be instantly adapted to the changing demands of the environment. Moreover, the resulting activities did not only take account of the environment but also of each other: they became coordinated and integrated. Responding appropriately to their sensory inputs, these creatures could now move about in search of food, or shelter, or a mate, instantly adjusting their movements to the perceived location of these things and to the varied demands of the terrain. But since all reactions were of the nature of innately fixed and stereotyped responses to the sensory inputs concerned, anything that differed from the norms to which evolution had adapted them was likely to prove disastrous. Thus if the head of a column of Processional Caterpillars is made to join its tail, the creatures will march in a circle until they die of starvation. In due course the mechanisms of natural selection produced yet another improvement: organisms capable of undergoing adaptive changes during their lifetime changes which matched the needs the individuals experienced in the ecological niche which the species had come to occupy. That is to say, they could learn from experience. All these changes were direcrive. hence 'teleological'. in the sense I have described: they matched the circumstances in which they took place in a manner conducive to some biologically significant end-result. In this sense, then, living organisms evolved as harmoniously operating, selfmaintaining and self-preserving, as well as self-reproducing, systems of immense sophistication and adaptive powers. A higher kind of order had come into being - the
2.2 - Dynamic versus structural order
41
dynamic order of a system in which all parts work together towards a common goal. The higher up we move in the scale of life the more impressive this kind of order becomes: impressive both in complexity and pexformance. The story of this organic order is no longer a story of potential energy minima and entropy changes. It is the story of countless interlocked, mutually coordinated, integrated and ingeniously orchestrated controls, regulations, checks, balances, error correcting mechanisms, and adaptive adjustments which, each in its own way, help the organism to maintain its structures and functions, and support its powers to meet the vicissitudes of its life with a vast battery of appropriately matched reactions and skilled behaviour patterns. And since, as I shall show, this type of order rests on distinctive patterns of causal relationships, we are dealing here with relationships in both space and time, i.e. with a four-dimensional rather than a three-dimensionaltype of order. This dynamic order is also the feature to which the living organism owes its distinctive kind of .unity. As Claude Bernard v o t e more than a century ago: "It is the subordination of the parts to the whole which makes of the complex creature a connected system, a whole, an individual". This is true enough. But it has to be realized, of course, that the subordination we are here talking about is again a teleological relationship. It is the subordination of the proximate goals of the individual activities of the parts of the organism to the requirements of the whole, and thus to the ultimate goal of their combined activities. The clarity of our perceptions i n this whole field, therefore, must depend on the clarity of our perceptions of teleological relationships as such. At the physiological level this subordination of the activities of the parts to the demands of the whole manifests itself inter alia in the intricate mechanisms through which the body achieves homeostasis, i.e. a constancy of the internal environment. Familiar examples are the constancy of the body temperature and of the blood concentrations. In the 1930s many of these aspects of organic function were for the first time brought to the attention of a wider public by Cannon's famous book THE WISDOM OF THE BODY (Cannon 1939). By that time even more impressive feats of regulation and control had also come to light in the field of embryology and morphogenesis, mainly in amphibians. People were frankly perplexed by such discoveries as the extent to which it is possible to reshuffle or even ablate cells in the early stages of an amphibian embryo, and still finish with a perfectly normal and viable adult specimen. Even up to the @cell stage the embryo can be divided along any plane into two halves and, yet, two normal adults will develop. Conversely, two early balls of cells can be fused together and a single normal adult will nevertheless result. Again, the amphibian limb bud may be divided into two or three parts and each part will grow into a complete limb; and - perhaps even more surprisingly - the developing eye bud can be transplanted to locations below the dorsal skin and the skin above the transplant will become transparent and develop into a cornea.
Ch.2 - Order and life
42
Such adaptive processes are not confined to the embryonic stage. In all higher animals there continues to exist a measure of adaptive plasticity well after birth and throughout most of the normal lifespan, except that this capacity diminishes with age so that eventually what will knock a young person down will knock an old person out. The most impressive development of this ontogenetic adaptability is, of course, our power to learn from experience. Yet, although the mechanisms of all this are often well understood, the whole question of the formal structure of the teleological characteristics of vital activities has remained an area of which the average biologist has only a hazy perception. If asked to translate statements containing teleological terms into statements containing only nonteleological terms, he would be hard put for an answer. Indeed, the question itself may strike him as rather too dangerously abstract. Unfortunately one cannot avoid abstract thought if one becomes involved with questions as general and fundamental as those that occupy us in this volume: and we shall find that to cope with these we need above all a set of precise and objective concepts that can be defined in non-teleologicalterms and yet capture the essence of the teleological relationships we are interested in. Past attempts of academic philosophers to analyse teleological concepts, have often resulted merely in a reduction of the concepts concerned to others of the same family. Indeed, this has throughout been a major stumbling block. In his recent TELEOLGY,for example, W d i e l d (1976) reduces them to the basic teleological concept of (organic) function. The philosophy of mind known as Functionalism also accepts function as a primitive concept. This is unacceptable to good systems-theory. It needs technical definitions of teleological concepts which are couched in strictly non- teleological terms, e.g. in terms of clearly stated patterns of causal relationships. The concept offunction is no exception.
*** 2.3
- THE RANGE AND IMPORTANCE OF TELEOLOGICAL CONCEPTS
In ordinary discourse we may well be satisfied that we know what is meant when the movements of the Cheetah are said to be instantly matched or adapted to the changing demands of the terrain, when they are described as highly coordinated or integrated', or to have organic unity; and when its limbs are said to move in perfect unity or perfect harmony. Again, we think we know what is meant when some physiological processes are said to be highly regulated or controlled, or when people speak of the function of an organ. But do we really have a clear idea of what exactly is being asserted in each case?
2.3 - The range and importance of teleological concepts
43
All these concepts are teleological concepts because they all relate to one or other manifestation or aspect of directive activity. And even among biologists they have remained fuzzy concepts. Thus although most biologists may be satisfied that they know what is meant by describing some animal movements as 'coordinated, few are likely to agree on the precise criteria that distinguish coordinated from uncoordinated movements, or what inferences can be drawn about the causal relationships involved when a set of movements are said to be coordinated; or what difference in causal relationships would make us say in one case that A is adapted to B and in another that B is adapted to A . At a more general level, few biologists are likely to agree on the objective criteria that distinguish a biological activity which is goal-directed in the sense I have illustrated, from one that is not. Again, few would be able to state of any given teleological concept what it implies in non-teleloligcal terms. This fuzziness of teleological concepts does not in general impede the work of biologists routinely, but it is unacceptable in the accurate analysis of brain functions we are aiming at - nor, indeed, in a serious discussion of the more abstract characteristics of the organic order of living systems as a whole. The general public, of course, tends to take the teleology of the living world very much for granted. In everyday life we invariably tend to classify the activities of animals, not according to the specific movements they execute, but according to the goals we attribute to those movements - as when we speak of 'flight from danger', 'attack', 'pursuit', 'escape', 'search', 'defence', 'nest- building', 'seeking a mate', 'caring for the offspring', etc. Again, our emotional reactions towards the animal world are mainly governed by the goals we attribute to their activities. We fear the power of a bull only because of the aggressive goals of which we hold it to be capable. And when your dog dies, you do not mourn the irreversible cessation of its metabolic processes: you mourn the cessation of the particular kind of purposeful responses that made the creature the good companion it was. Indeed, our emotional attitudes towards our animal friends, be they dogs, cats or horses, depends in a large measure on the extent to which we can read purposes into their behaviours - and preferably purposes with which we can identify - as when we say of a dog that "she craves attention", "wants to be taken for a walk". "has a guilty conscience", etc. This directiveness is also the one characteristic of observed life which invites us to think of living things as somehow endowed with a soul (the original 'animal of 'animate matter'). Regardless of whether this response is scientifically sound, the fact remains that it forms the basis of any kind of empathy we are able to feel for the living world and the basis of our sense of union with that world - a topic to which I shall return in Chapters 10 and 11. On all these counts, one can say that it is the directiveness of vital activities which gives to the distinction between living and non-living systems the outstanding significance it has in our daily affairs. In this sense it is to us a far more important quality
Ch.2 - Order and life
44
than any of the scientific distinctions between living and non-living objects that we are taught at school - such as growth, reproduction, respiration, water and food intake, disposal of waste products, responsiveness to stimuli and the like. Whatever the schoolbooks may say, if you were to meet some unknown object on a foreign planet, your first instinct would be to prod it to see if its response would be a blindly inert one or a somehow directive one. And if the latter, you would place it on the scale of life, or class it as friendly or hostile, according to the direction and degree of directiveness of its responses. You would not examine its metabolism.
*** 2.4
- PAST MISCONCEPTIONS
Conceptual confusions have bedeviled discussions about the meaning and significance of teleological phenomena ever since Aristotle first drew attention to the "absence of haphazard and conduciveness of everything to an end' in living nature. They have left their mark not only on the history of biology but also on the history of philosophy and theology. Largely responsible for these confusions has been the fact that this aspect of living matter often seemed hard to reconcile with the blind determinism of the laws of physics and chemistry. Thus the 'Vitalists' of the 18th. 19th and beginning of the 20th century argued that it required the existence of forces in living matter which differed in kind from any of the forces found in non-living matter - forces which in some sense seemed to be forward looking. Bergson called it the 'elan vital' of living organisms, Driesch their 'entelechy'. Other thinkers have gone further and argued that the teleology of living nature demonstrates the presence of Mind or Supreme Intelligence in the universe. This vision, too, has a venerable history. No one has expressed it better than Virgil after reflecting on the life of the honey bee and on the manifest purposefulness and harmony of the teeming activities in the hive:"These acts and powers observing, some declare That bees have portion in the mind of God And life from heaven derive, that God pervades All lands, the oceans, plains, the abyss of heaven And that from Him flocks, cattle, princely men, All breeds of creatures wild receive at birth Each his frail,vital breath; that whence they came All turn again dissolving." (4th Book of the Georgics)
2.4 - Past misconceptions
45
To-day there are still many who who see in such images and inferences the foundations of a Natural Theology. I would not wish to dispute that such imagery has a valid place in religion as part of the image-driven way in which religion helps man to relate himself to the nature of life and the conditions of human existence. But it is a fallacy to hold that we are dealing here with phenomena from whose objective description logical inferences can be drawn about the existence of some transcendent mental or spiritual entity. That, in the objective sense I have described, there exist a multitude of teleological systems in living nature, cannot be denied. But anyone who would wish to make this the cornerstone of a Natural Theology would have to show in the same objective terms that in addition to these individual teleological systems there exists one single comprehensive teleological system that embraces them all - and, indeed the whole universe. In the early years of this century, and mainly in response to the astonishing discoveries that had been made in the field of embryology, another school of thought found some favour. This attributed the 'organic wholeness' of an organism to an 'overall plan' which had some kind of transcendental power to restrain the development and activities of the organism and its parts. However, already in those days, leading biologists set themselves against these 'organistic' schools of thought and warned about the lack of explanatory value of illdefined terms like 'organic whole', 'organic part' and 'organizing relation'. More than half a century ago, Woodger (1929) wrote: "It is easy enough to see 'intuitively' what is meant by these terms.......;the
difficulty is to make these notions precise in order to enable us to see how we can use them for scientific purposes. Intuition is the indispensable cutting edge of intellectual enquiry, but the ground won is not consolidated until it has passed from the stage of intuitive apprehension to that of logical analysis.'' Yet for many years to come his remained a voice in the wilderness. Until after the Second World War, when cyberneticists and robot engineers began to apply mathematical analyses to the variety of directive activities they were seeking to achieve in their artefacts, the whole realm of concepts relating to organic order and organization remained a foggy one indeed. In sharp opposition to the Vitalists and Organicists stood a radically mechanistic school of biological thought which dismissed the whole concept of goal-directed activity in living nature as a figment of the imagination. According to this school. the notion of directivenessin vital activities is a mere by-product of a human tendency to project man's own conscious purposiveness and rationality into the environment - in other words, a mere anthropomorphism or primitive aninlism. Indeed, there were times when even such
Ch.2 - Order and life
46
innocent statements as that an animal was trying to escape from its cage might earn an examination candidate a negative mark. This outright rejection of all teleological concepts was at its most influential in the fiist half of this century. Since then is has had to retreat step by step as logical and mathematical analysis came to establish beyond doubt that the goal-hctedness of vital activities can be characterized in objective terms. At the same time the development of feedback-controlled servo-mechanisms and robotics furnished the world with machine examples of activities which were patently goal-directed in an objective sense - and yet clearly ran their course without the intervention of 'mind'. Few things can be more patently goal- directed than the flight of a homing missile. Even so, the old arguments have not yet been wholly laid to rest. Time and again tracts still appear which claim that this directiveness in living nature points to a conscious design. Some even claim that this insight is the hallmark of "a new biology" (Peacocke, 1986; A u p s and Stanciu, 1987).
***
ORDER AND LIFE
INTRODUCTION AND SUMMARY In this and the next chapter I shall deal with some of the basic concepts of systems-theory when applied to living systems and to the general character of their organization. Since this is likely to be familiar ground for only a minority of readers, I shall d o SO into considerable detail. Most of this turns on the requirements of systems-theory to work only with concepts which can be accurately defined on the observable variables and assumed parameters of the systems under consideration. This covers more than just variables relating to their outward behaviour. It includes any variable whose value can in principle be determined by scientific means, internal variables as well as surface variables. Certain features of the activities of living systems will here attract our main attention, especially the directiveness which I discussed briefly in Section 1.7. When we come to describe certain states and activities in the brain which will prove to be relevant to our enquiry, we shall be characterizing some of these activities as appropriately related to the circumstances in which they occur; others will be described as adaptive; again others as coordinated, or as serving some particularfinction. All of these concepts relate to manifestations of that directiveness. We shall also be talking about states of readiness of the brain for some particular events, and about a subcategory of this which will be called states of expectancy. And for the purpose of our analysis we shall need a clear perception of what exactly is meant on all of these occasions and what each of the concepts implies by way of spatio-temporal and in particular, causal relationships. This conceptual clarity is also important if we are to relate our findings to the structure of brain functions in a manner that can be accurately formulated.
Ch.2 - Order and life.
38
Even so, the reader whose main interest lies in the conclusions we shall reach and in the postulates on which they rest, may omit these two chapters at a first reading, refemng back to them only when the need arises.
*** 2.1
- THE DIRECTIVENESS OF VITAL ACTIVITIES
Human beings are living organisms and living organisms are physical systems in the sense in which this term is now generally understood. But they are physical systems of peculiar kind. For, superimposed on the kind of orderliness that we can also find in nonliving systems, e.g. the orderly arrangement of atoms in a molecule or crystal, living systems have another kind of orderliness which we call their organization. It manifests itself in processes which we describe in such terms as regulation, control, adaptation, coordination, integration, and function. Consciousness is one of the most sophisticated manifestations of this organization, and if we want to understand consciousness in its full biological context, it is imperative to start with a clear idea of the distinctive type of orderliness which characterizes this organization, e.g. a clear idea of the general pattern of causal relationships on which it depends. We need this clear idea not only to be able to give precise physical definitions to the many (in general use still fuzzy) biological concepts which relate to it, but also to get a better perception of the general nature of the organic order in which the life of all human beings is embedded, and of the kind of harmony that it appears to produce within its sphere. For in the final chapters of this book I shall relate some aspects of the human psyche to the nature of this harmony and man's intuitive awareness of it. At the most general level, this organic orderliness manifests itselfin one of the most distinctive characteristics of living organisms, viz., the directiveness or goal-directedness of their activities or processes. Whatever you see happening in the living world, especially in the higher orders of life, generally seems to be directed towards the production of some biologically significant end-result: the organism crawls, runs, swims, or flies to get from A to B; it gathers food to fuel its energies; it hides to escape detection; it fights to protect its temtory; it burrows or builds a nest for shelter, it finds a mate in order to reproduce, and so on. Meanwhile its body performs a multitude of internal regulations to safeguard the constancy of the internal environment and to keep itself going as an effectively operating survival machine. In each case the actions or processes in question are seen to be directed towards the achievement of that end-result in the manifest sense that they are seen to be produced or controlled in such a way that over a variety of circumstances they will match those circumstances in a manner conducive to the end-result in question. If the mouse jumps to the left so will the cat.
2 2 - Dynamic versus structural order
39
This directiveness characterizes not only the behavioural responses and physiological reactions of the living organism, but also the much slower processes of ontogenetic development, maturation and learning. In a slightly more restricted sense, it characterizes also the long-drawn-out processes of evolution. For here, too, we see developments taking place which are able to match changes in the ecological conditions in a manner that is conducive to some biologically significant end-result. This, and no more than this, is what I shall mean by the teleological character of vital activities, while by teleological terms or concepts I shall mean all terms or concepts that relate to this directiveness or aspects of it. Many modem artefacts also achieve such directive behaviour, notably artefacts governed by servomechanisms incorporating negative feedback loops. The autopilots of ships and aircraft are typical examples. So are industrial robots and homing missiles. However, we cannot use the concept of feedback loop itself to characterize in objective and sufficiently general terms the nature of directive activities as such. To that end we need a characterization of what is achieved by such mechanisms, not an account of how it is achieved. And a more abstract analysis is required for that purpose. (Readers who are unfamiliar with the notion of 'feedback loop' will find the feedback system of a simple servomechanism illustrated in Fig. 3.1). It will be clear from the above remarks that the 'goal- directedness' of organic activities which I have described, is here viewed as an objective characteristic of the activities concerned, a characteristic which they share with the flight of a homing missile, for example. Unfortunately, such activities are also often described as 'purposeful' or 'purposive', and these terms have obvious mental connotations. They suggest the intervention of a mind motivated by conscious aims. It is important, therefore, not to confuse our objective sense of goal-dmctedness with this subjective or mental sense or purposiveness. The goal-directedness we are talking about does not imply the intervention of a mind at all. Moreover, although rational mental activity may well be regarded as nature's most sophisticated way of producing activities which are also goaldirected in an objective sense, it is not an infallible way. A human action may well be a purposeful one in the above subjective sense without satisfying also the criteria of goaldirectedness in the objective sense I have described. One can have a defmite goal in mind and yet do all the wrongs things.
***
2.2
- DYNAMIC
VERSUS STRUCTURAL ORDER
The story of life can be told at several distinct levels. One of these is the molecular and cellular level. This is the story of the macromolecules of which living cells and tissues are constructed: the story of DNA, RNA, genes, chromosomes, enzymes, and so on. The type of order that comes into focus at this level is mainly a geomemcal, three-dimensional
40
Ch.2 - Order and life
order: the orderly arrangement of atoms in molecules and of molecules in paracrystals, cellular membranes, tissue fibres, and other structures. It is a type of order which can be quantified in terms of negative entropy, because the thermo-statistical concept of entropy itself is a measure of the disorder that exists in a physical system at any given point of time. All the most spectacular advances of biology in this century have been made at this, the molecular level. But this is not the only level at which the story of life can be told. Inanimate objects are wholly at the mercy of their environment. The extent to which they can resist disruptive forces depends solely on the depth of the potential energy minimum which their physical structure occupies. Any physical force strong enough to lift it out of that minimum and over the surrounding 'energy humps' will prove disruptive. However, with the arrival of life, a new factor appeared on the scene, capable of ensuring endurance in the face of adverse environmental contingencies: systems appeared which had the capacity over long periods of time (spanning many generations) to undergo adaptive changes - that is, changes which were related to the characteristics of the environment in a way that increased the probability of survival. In due course a further improvement occurred: these slow evolutionary changes resulted in the development of mechanisms which could pick up information about the current state of the environment and produce behaviours which could be instantly adapted to the changing demands of the environment. Moreover, the resulting activities did not only take account of the environment but also of each other: they became coordinated and integrated. Responding appropriately to their sensory inputs, these creatures could now move about in search of food, or shelter, or a mate, instantly adjusting their movements to the perceived location of these things and to the varied demands of the terrain. But since all reactions were of the nature of innately fixed and stereotyped responses to the sensory inputs concerned, anything that differed from the norms to which evolution had adapted them was likely to prove disastrous. Thus if the head of a column of Processional Caterpillars is made to join its tail, the creatures will march in a circle until they die of starvation. In due course the mechanisms of natural selection produced yet another improvement: organisms capable of undergoing adaptive changes during their lifetime changes which matched the needs the individuals experienced in the ecological niche which the species had come to occupy. That is to say, they could learn from experience. All these changes were direcrive. hence 'teleological'. in the sense I have described: they matched the circumstances in which they took place in a manner conducive to some biologically significant end-result. In this sense, then, living organisms evolved as harmoniously operating, selfmaintaining and self-preserving, as well as self-reproducing, systems of immense sophistication and adaptive powers. A higher kind of order had come into being - the
2.2 - Dynamic versus structural order
41
dynamic order of a system in which all parts work together towards a common goal. The higher up we move in the scale of life the more impressive this kind of order becomes: impressive both in complexity and pexformance. The story of this organic order is no longer a story of potential energy minima and entropy changes. It is the story of countless interlocked, mutually coordinated, integrated and ingeniously orchestrated controls, regulations, checks, balances, error correcting mechanisms, and adaptive adjustments which, each in its own way, help the organism to maintain its structures and functions, and support its powers to meet the vicissitudes of its life with a vast battery of appropriately matched reactions and skilled behaviour patterns. And since, as I shall show, this type of order rests on distinctive patterns of causal relationships, we are dealing here with relationships in both space and time, i.e. with a four-dimensional rather than a three-dimensionaltype of order. This dynamic order is also the feature to which the living organism owes its distinctive kind of .unity. As Claude Bernard v o t e more than a century ago: "It is the subordination of the parts to the whole which makes of the complex creature a connected system, a whole, an individual". This is true enough. But it has to be realized, of course, that the subordination we are here talking about is again a teleological relationship. It is the subordination of the proximate goals of the individual activities of the parts of the organism to the requirements of the whole, and thus to the ultimate goal of their combined activities. The clarity of our perceptions i n this whole field, therefore, must depend on the clarity of our perceptions of teleological relationships as such. At the physiological level this subordination of the activities of the parts to the demands of the whole manifests itself inter alia in the intricate mechanisms through which the body achieves homeostasis, i.e. a constancy of the internal environment. Familiar examples are the constancy of the body temperature and of the blood concentrations. In the 1930s many of these aspects of organic function were for the first time brought to the attention of a wider public by Cannon's famous book THE WISDOM OF THE BODY (Cannon 1939). By that time even more impressive feats of regulation and control had also come to light in the field of embryology and morphogenesis, mainly in amphibians. People were frankly perplexed by such discoveries as the extent to which it is possible to reshuffle or even ablate cells in the early stages of an amphibian embryo, and still finish with a perfectly normal and viable adult specimen. Even up to the @cell stage the embryo can be divided along any plane into two halves and, yet, two normal adults will develop. Conversely, two early balls of cells can be fused together and a single normal adult will nevertheless result. Again, the amphibian limb bud may be divided into two or three parts and each part will grow into a complete limb; and - perhaps even more surprisingly - the developing eye bud can be transplanted to locations below the dorsal skin and the skin above the transplant will become transparent and develop into a cornea.
Ch.2 - Order and life
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Such adaptive processes are not confined to the embryonic stage. In all higher animals there continues to exist a measure of adaptive plasticity well after birth and throughout most of the normal lifespan, except that this capacity diminishes with age so that eventually what will knock a young person down will knock an old person out. The most impressive development of this ontogenetic adaptability is, of course, our power to learn from experience. Yet, although the mechanisms of all this are often well understood, the whole question of the formal structure of the teleological characteristics of vital activities has remained an area of which the average biologist has only a hazy perception. If asked to translate statements containing teleological terms into statements containing only nonteleological terms, he would be hard put for an answer. Indeed, the question itself may strike him as rather too dangerously abstract. Unfortunately one cannot avoid abstract thought if one becomes involved with questions as general and fundamental as those that occupy us in this volume: and we shall find that to cope with these we need above all a set of precise and objective concepts that can be defined in non-teleologicalterms and yet capture the essence of the teleological relationships we are interested in. Past attempts of academic philosophers to analyse teleological concepts, have often resulted merely in a reduction of the concepts concerned to others of the same family. Indeed, this has throughout been a major stumbling block. In his recent TELEOLGY,for example, W d i e l d (1976) reduces them to the basic teleological concept of (organic) function. The philosophy of mind known as Functionalism also accepts function as a primitive concept. This is unacceptable to good systems-theory. It needs technical definitions of teleological concepts which are couched in strictly non- teleological terms, e.g. in terms of clearly stated patterns of causal relationships. The concept offunction is no exception.
*** 2.3
- THE RANGE AND IMPORTANCE OF TELEOLOGICAL CONCEPTS
In ordinary discourse we may well be satisfied that we know what is meant when the movements of the Cheetah are said to be instantly matched or adapted to the changing demands of the terrain, when they are described as highly coordinated or integrated', or to have organic unity; and when its limbs are said to move in perfect unity or perfect harmony. Again, we think we know what is meant when some physiological processes are said to be highly regulated or controlled, or when people speak of the function of an organ. But do we really have a clear idea of what exactly is being asserted in each case?
2.3 - The range and importance of teleological concepts
43
All these concepts are teleological concepts because they all relate to one or other manifestation or aspect of directive activity. And even among biologists they have remained fuzzy concepts. Thus although most biologists may be satisfied that they know what is meant by describing some animal movements as 'coordinated, few are likely to agree on the precise criteria that distinguish coordinated from uncoordinated movements, or what inferences can be drawn about the causal relationships involved when a set of movements are said to be coordinated; or what difference in causal relationships would make us say in one case that A is adapted to B and in another that B is adapted to A . At a more general level, few biologists are likely to agree on the objective criteria that distinguish a biological activity which is goal-directed in the sense I have illustrated, from one that is not. Again, few would be able to state of any given teleological concept what it implies in non-teleloligcal terms. This fuzziness of teleological concepts does not in general impede the work of biologists routinely, but it is unacceptable in the accurate analysis of brain functions we are aiming at - nor, indeed, in a serious discussion of the more abstract characteristics of the organic order of living systems as a whole. The general public, of course, tends to take the teleology of the living world very much for granted. In everyday life we invariably tend to classify the activities of animals, not according to the specific movements they execute, but according to the goals we attribute to those movements - as when we speak of 'flight from danger', 'attack', 'pursuit', 'escape', 'search', 'defence', 'nest- building', 'seeking a mate', 'caring for the offspring', etc. Again, our emotional reactions towards the animal world are mainly governed by the goals we attribute to their activities. We fear the power of a bull only because of the aggressive goals of which we hold it to be capable. And when your dog dies, you do not mourn the irreversible cessation of its metabolic processes: you mourn the cessation of the particular kind of purposeful responses that made the creature the good companion it was. Indeed, our emotional attitudes towards our animal friends, be they dogs, cats or horses, depends in a large measure on the extent to which we can read purposes into their behaviours - and preferably purposes with which we can identify - as when we say of a dog that "she craves attention", "wants to be taken for a walk". "has a guilty conscience", etc. This directiveness is also the one characteristic of observed life which invites us to think of living things as somehow endowed with a soul (the original 'animal of 'animate matter'). Regardless of whether this response is scientifically sound, the fact remains that it forms the basis of any kind of empathy we are able to feel for the living world and the basis of our sense of union with that world - a topic to which I shall return in Chapters 10 and 11. On all these counts, one can say that it is the directiveness of vital activities which gives to the distinction between living and non-living systems the outstanding significance it has in our daily affairs. In this sense it is to us a far more important quality
Ch.2 - Order and life
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than any of the scientific distinctions between living and non-living objects that we are taught at school - such as growth, reproduction, respiration, water and food intake, disposal of waste products, responsiveness to stimuli and the like. Whatever the schoolbooks may say, if you were to meet some unknown object on a foreign planet, your first instinct would be to prod it to see if its response would be a blindly inert one or a somehow directive one. And if the latter, you would place it on the scale of life, or class it as friendly or hostile, according to the direction and degree of directiveness of its responses. You would not examine its metabolism.
*** 2.4
- PAST MISCONCEPTIONS
Conceptual confusions have bedeviled discussions about the meaning and significance of teleological phenomena ever since Aristotle first drew attention to the "absence of haphazard and conduciveness of everything to an end' in living nature. They have left their mark not only on the history of biology but also on the history of philosophy and theology. Largely responsible for these confusions has been the fact that this aspect of living matter often seemed hard to reconcile with the blind determinism of the laws of physics and chemistry. Thus the 'Vitalists' of the 18th. 19th and beginning of the 20th century argued that it required the existence of forces in living matter which differed in kind from any of the forces found in non-living matter - forces which in some sense seemed to be forward looking. Bergson called it the 'elan vital' of living organisms, Driesch their 'entelechy'. Other thinkers have gone further and argued that the teleology of living nature demonstrates the presence of Mind or Supreme Intelligence in the universe. This vision, too, has a venerable history. No one has expressed it better than Virgil after reflecting on the life of the honey bee and on the manifest purposefulness and harmony of the teeming activities in the hive:"These acts and powers observing, some declare That bees have portion in the mind of God And life from heaven derive, that God pervades All lands, the oceans, plains, the abyss of heaven And that from Him flocks, cattle, princely men, All breeds of creatures wild receive at birth Each his frail,vital breath; that whence they came All turn again dissolving." (4th Book of the Georgics)
2.4 - Past misconceptions
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To-day there are still many who who see in such images and inferences the foundations of a Natural Theology. I would not wish to dispute that such imagery has a valid place in religion as part of the image-driven way in which religion helps man to relate himself to the nature of life and the conditions of human existence. But it is a fallacy to hold that we are dealing here with phenomena from whose objective description logical inferences can be drawn about the existence of some transcendent mental or spiritual entity. That, in the objective sense I have described, there exist a multitude of teleological systems in living nature, cannot be denied. But anyone who would wish to make this the cornerstone of a Natural Theology would have to show in the same objective terms that in addition to these individual teleological systems there exists one single comprehensive teleological system that embraces them all - and, indeed the whole universe. In the early years of this century, and mainly in response to the astonishing discoveries that had been made in the field of embryology, another school of thought found some favour. This attributed the 'organic wholeness' of an organism to an 'overall plan' which had some kind of transcendental power to restrain the development and activities of the organism and its parts. However, already in those days, leading biologists set themselves against these 'organistic' schools of thought and warned about the lack of explanatory value of illdefined terms like 'organic whole', 'organic part' and 'organizing relation'. More than half a century ago, Woodger (1929) wrote: "It is easy enough to see 'intuitively' what is meant by these terms.......;the
difficulty is to make these notions precise in order to enable us to see how we can use them for scientific purposes. Intuition is the indispensable cutting edge of intellectual enquiry, but the ground won is not consolidated until it has passed from the stage of intuitive apprehension to that of logical analysis.'' Yet for many years to come his remained a voice in the wilderness. Until after the Second World War, when cyberneticists and robot engineers began to apply mathematical analyses to the variety of directive activities they were seeking to achieve in their artefacts, the whole realm of concepts relating to organic order and organization remained a foggy one indeed. In sharp opposition to the Vitalists and Organicists stood a radically mechanistic school of biological thought which dismissed the whole concept of goal-directed activity in living nature as a figment of the imagination. According to this school. the notion of directivenessin vital activities is a mere by-product of a human tendency to project man's own conscious purposiveness and rationality into the environment - in other words, a mere anthropomorphism or primitive aninlism. Indeed, there were times when even such
Ch.2 - Order and life
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innocent statements as that an animal was trying to escape from its cage might earn an examination candidate a negative mark. This outright rejection of all teleological concepts was at its most influential in the fiist half of this century. Since then is has had to retreat step by step as logical and mathematical analysis came to establish beyond doubt that the goal-hctedness of vital activities can be characterized in objective terms. At the same time the development of feedback-controlled servo-mechanisms and robotics furnished the world with machine examples of activities which were patently goal-directed in an objective sense - and yet clearly ran their course without the intervention of 'mind'. Few things can be more patently goal- directed than the flight of a homing missile. Even so, the old arguments have not yet been wholly laid to rest. Time and again tracts still appear which claim that this directiveness in living nature points to a conscious design. Some even claim that this insight is the hallmark of "a new biology" (Peacocke, 1986; A u p s and Stanciu, 1987).
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