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1 This view of the cell is briefly outlined in J. G. Adami ,7 be Principles of Pathology , vol. i, London, 1908, pp. 37-8. It is implicit in Sachs’s ‘energid’ theory.
1 This view of the cell is briefly outlined in J. G. Adami ,7 be Principles of Pathology , vol. i, London, 1908, pp. 37-8. It is implicit in Sachs’s ‘energid’ theory.
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Russell ES. The interpretation of development and heredity. (1930) Oxford. Univ. Press.
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X The Organismal Point of View
Materialism as a philosophical doctrine has long been dead, and as a scientific method its limitations are now becoming apparent. Even in their application to physics, in which field they originated and won their most striking triumphs, the simple mechanistic principles are proving inadequate in face of the new facts and the new conceptions.
‘The progress of science’, writes Whitehead, 1 ‘has now reached a turning point. The stable foundations of physics have broken up: also for the first time physiology is asserting itself as an effective body of knowledge, as distinct from a scrap-heap. The old foundations of scientific thought are becoming unintelligible. Time, space, matter, material, ether, electricity, mechanism, organism, configuration, pattern, function, all require reinterpretation. What is the sense of talking about a mechanical explanation when you do not know what you mean by mechanics ?’
‘The appeal to mechanism on behalf of biology was in its origin an appeal to the well-attested self-consistent physical concepts as expressing the basis of all natural phenomena. But at present there is no such system of concepts’ (ibid., p. 129).
The fact is that biology, impressed by the success of physical concepts in their own sphere at the time of the great development of the classical mechanics, took over to itself concepts and methods which were clearly inappropriate and inadequate to the new subject. Now these concepts are found to be unsatisfactory even in their original sphere; in particular, the configuration idea has gone, and with it the old Laplacean conception of universal material determinism . 2
1 A. N. Whitehead, Science and the Modern World , Cambridge, 1926, p. 21. a Cf. Professor A. S. Eddington: ‘On the scientific side, a new situation has arisen. It is a consequence of the advent of the quantum theory that physics is no longer pledged to a scheme of deterministic law. Determinism has dropped out altogether in the latest formulations of theoretical physics and it is at least open to doubt whether it will ever be brought back. . . . The future is a combination of the causal influence of the past, together with unpredictable elements — unpredictable not merely The philosophical foundations of mechanistic biology have crumbled away.
2. What we have to do then is to look round for a new set of concepts which will enable us to establish biology on a footing of its own. These new concepts must of course link up with those of the new physics on the one hand and with psychological principles on the other. The task is not a simple one, considering that neither physics nor psychology has yet come to any settled agreement regarding its own guiding ideas.
It is particularly in connexion with studies of the developing organism that we feel the need of special biological concepts, for the adult and finished organism may be regarded from the point of view of physiology as approximating sufficiently nearly to a mechanism to be treated as such, provided the principle of wholeness or unity be recognized. The same is, however, not true of the developing organism, as Sir Charles Sherrington has pointed out in his Presidential Address to the British Association in 1922.
‘Of not a few of the processes of the living body,’ he writes, ‘such as muscular contraction, the circulation of the blood, the respiratory intake and output by the lungs, the nervous impulse and its journeyings, we may fairly feel, from what we know of them already, that further application of physics and chemistry will furnish a competent key. . . . Turning to other aspects of animal mechanism such as the shaping of the animal body, the conspiring of its structural units to compass later functional ends, the predetermination of specific growth from egg to adult, the predetermined natural term of existence, these and their intimate mechanism, we are, it seems to me, despite many brilliant enquiries and enquirers, still at a loss to understand.’ 1
because it is impracticable to obtain the data of prediction, but because no data connected causally with our experience exist.’ The Nature of the Physical World , Cambridge, 1929, p. 294.
1 Cf. Claude Bernard: ‘II y a dans un ph^nomene vital, comme dans tout autre ph£nom£ne naturel, deux ordres de causes: d’abord une cause premiere, cr£atrice, legislative et directrice de la vie, et inaccessible & nos connaissances, ensuite une cause prochaine ou executive du ph£nomene vital qui toujours est de nature physicochimique et tombe dans le domaine de l’experimentatcur. La cause premiere de la vie donne revolution ou la creation de la machine organisee; mais la machine, une fois creee, fonctionnc en vertu des proprietes de ses elements constituants et sous l’in
Nor are mechanistic concepts really applicable to many of the broader problems of general biology — problems of adaptation, of behaviour, of the factors of evolution. From a strictly mechanistic point of view there is no adaptation, there is no behaviour — there is only a series of material configurations in course of transformation. So-called mechanistic theories of evolution have been from time to time propounded on the basis of random variation and chance selection, but these are neither factually nor logically sound, and carefully ignore most of the obvious features of the process which they purport to explain.
3. The vitalistic solution of the problem of biological method offered by Dricsch cannot be accepted as really satisfactory, for the reason that it does not lead to any distinctively new method of attack. It is, in practice, materialism plus an entelechy — abstraction of the psychical has taken place. The critical and destructive side of Driesch’s work is admirable; his system of philosophy merits the most careful study; but his entelechy is of no practical use as a biological concept. 1
4. The proper alternative to the mechanistic method in biology is in a sense obvious and lies on the surface. It is suggested by ordinary commonsense acceptance of the plain facts without abstraction, and it is in effect used by biologists to a very great extent, whatever their theoretical views may be. Common observation shows us that vital activities are manifested by individuals , whether unicellular or multicellular. Even from the point of view of structure, life is not a property of any substance, however complex, but of an organization. The idea of ‘living substance’ is, as we have seen, a pure abstraction, to which nothing corresponds in Nature. The ascription to sub-cellular and abstract vital units such as biophors and determinants of the full properties of life is likewise inadmissible. The lowest unit that
fluence des conditions physico-chimiques qui agissent sur eux/ La Science experimentale , Paris, 1890, pp. 53-4.
1 For a fuller treatment of Driesch’s views sec The Study of Living Things, 1924, pp. 20 -6.
shows the full range of vital activities and is independently viable is the cell-organism, whether in an elementary form with scattered chromatin, as in some bacteria and algae, or in a more evolved form with definite distinction of nucleus and cytoplasm. This statement may require some modification when more is known of ultra-microscopic, filter-passing ‘organisms’, but proof of their independent life seems still to be lacking . 1
From the point of view of function, the unique character of the living individual as the fundamental unit of biology stands out unmistakably, for the individual is essentially a functional unity, whose activities are co-ordinated and directed towards the development, maintenance, and reproduction of the form and modes of action typical of the species to which it belongs. To quote Sherrington again: ‘. . . the living creature is fundamentally a unity. In trying to make the “how” of an animal existence intelligible to our imperfect knowledge, we have, for purposes of study, to separate its whole into part -aspects and part -mechanisms, but that separation is artificial. It is as a whole, a single entity, that the animal, or for that matter the plant, is finally and essentially to be envisaged .’ 2
There is an interesting parallel in an old Address by St. George Mivart:
‘But as each living creature is a highly complex unity — both a unity of body and also a unity of force, or a synthesis of activities — it seems to me’, he writes, ‘that we require a distinct kind of physiology to be devoted to the investigation of such syntheses of activities as exist in each kind of living creature. I mean to say that just as we have a physiology devoted to the several activities of the several organs, so we need a physiology specially directed to the physiology of the living body considered as one whole, that is, to the power which is the function, so to speak, of that whole, and of which the whole body in its totality is the organ. In a word, we need a physiology of the individual .’ 3
See A. E. Boycott, ‘The transition from Live to Dead: the Nature of Filtrable Viruses’, Proc. Roy. Soc. Medicine , xxii (Path.), pp. 55-69, 1928.
1 Presidential Address to the British Association, 1922.
Address to the British Association, 1879. Reprinted in Essays and Criticisms, vol. ii, London, 1892. See p. 223.
The importance of the unity of the developing individual is stressed also by Claude Bernard, who writes: ‘En disant que la vie est l’idee directrice ou la force evolutive de l’etre, nous exprimons simplement l’idee d’une unite dans la succession de tous les changements morphologiques et chimiques accomplis par le germe depuis l’origine jusqu’a la fin de la vie’ (1890, p. 430).
As to the facts there can be no difference of opinion; the obvious conclusion to be drawn is that biology should be the science of individual living organisms.
This is in practice, as we have said, recognized by most biologists ; they deal in the course of their work with organisms as units, and necessarily employ expressions and concepts which relate specifically to organisms and are not applicable to inorganic objects. ‘As a matter of fact,’ writes MacBride in an article on Vitalism, ‘the ordinary biologist, however materialistic he may profess himself in theory, does not in practice avail himself of the “machine comparisons” in order to explain the activities of living beings, but takes such biological concepts as “stimulus”, “reaction”, and “adaptability” — which are certainly neither physical nor chemical ideas — as the building stones of the theories which he constructs.’ 1 This being the case, need we look farther for the biological principles we require ? That biology is essentially the study of living individuals is common ground. Can we not, from this starting-point, develop the principles of an autonomous biology ?
5. Everything depends of course upon what conception we form of ‘organism’. If we take ‘organism’ in a general sense as being merely a provisional concept, and straightway proceed to abstract from the psychical aspect and to treat the living thing as being only a complicated mechanism, if we go on to analyse its activities into part-aspects and partprocesses which are necessarily abstract, we fall back into the analytic and materialistic interpretation. It is true that even on this interpretation there would still be room for provisional generalizations, having the value of temporary biological laws. 1 W. Roux for instance regarded the establishment of the general functions or modes of action of living cells and tissues (his ‘complex components’) as a necessary preliminary to the complete analysis of these modes of action into their simple or physico-chemical components, but such laws would be superseded as soon as the physicochemical determinism was discovered of the processes they described. There is, however — and this is the essential point — no need for biology to be limited by the materialistic postulates; it is perfectly possible to frame a working conception of organism which shall be less abstract than that of mechanism and shall do less violence to the essential facts.
1 Scientia , July 1922, p. 23 of the separate copy.
6. Let us see if we can formulate such a conception. In the first place, the functional unity of the living thing must be emphasized. The activities of the parts work together for the good of the whole; the meaning of any functional activity can be understood only if its relation to the activity of the whole is known. It is not really possible to study adequately any one function, e.g. excretion, without taking into account its relations to other functions and conditions, as assimilation, circulation, the composition of the internal medium, and so on, and without determining what part it plays in the economy of the whole. This teleological conception can, however, be applied also to a machine ; this also is a unity, in which each part has a definite role to play in relation to the functioning of the machine as a whole. But as we saw in the last chapter (pp. 146-9), a machine can properly be analysed into constituent and independent parts, whereas in the living organism separate parts * can be distinguished only by the artifice of abstraction, and its unity is not decomposable without loss. The organism differs from the machine also in another respect, in that all its functions are directed to one or other of three great ends, namely the development of specific form and activities, the maintenance or restoration of such typical form and activities, and the reproduction of specific type. None of these broad characteristics of living things is shared by any machine.
1 I took this point of view in 191 1, in an article on ‘Vitalism’ in Scientia ( Rivista di Sctenza ), ix. 320-45.
We must therefore add to our first point — that the organism is a functional unity — the further characteristic that the functional activities of the living thing are essentially related to the ends of development, maintenance, and reproduction. Implied in this fuller definition are certain temporal relations of vital activities which are fundamental for our conception of organism. The organism is not , like a machine, a static construction, but a constantly changing organization of functional activities, which tends towards some end, and in such tendency is influenced by its past. Its activity is related both to its past and to its future.
That these are not vague general assertions made to bolster up a preconceived notion of the organism is made clear if we consider fairly and with an open mind the general activities of living things. That in development there is a definite progression to an end or goal, i.e. a reference to the future, cannot be denied. That the course of development is essentially influenced by the past history of the race is likewise difficult to deny, and we sum up such facts of the historical background of development in the laws of heredity and recapitulation. The reference to past and future is clear also in all cases of restitution or regeneration, and it is so obvious in behaviour as to need no pointing out. Reproduction too is essentially a preparation for the future, and its course is determined and defined by what, for want of a better word, one might call the organic tradition handed down by countless ancestors.
Let it be made quite clear that this reference to past and future is not necessarily or usually (so far as we know) a conscious reference on the part of the organism. It is, for example, necessary for description and understanding of the bald facts that we use the word ‘end’ in considering the phenomena of development, but it is not implied that the developing organism is conscious of the end or purpose which appears to us to be embodied in its development. Whether the organism makes conscious reference to the past and the future is really a point of minor importance; what is important to realize is that organic activities are objectively of such a character that we cannot fully understand them unless we consider them in relation both to the past and to the future of the organism. 1 The question as to what underlies this apparent reference behind and before in vital activities — whether it is conscious effort, as Samuel Butler was disposed to believe, or unconscious striving, as others think — is hardly one for biology, but rather for philosophy, to decide. That something does underlie it, that there is some real ground for the objective purposiveness of living things, is all we need postulate for our new biology.
We include then in our concept of organism the characteristic that vital activities have a reference to the future of the organism and are influenced in their course by the past history of the organism and of its ancestors. Exactly how this reference is effected by the organism itself, or even whether it is effected by the organism qua individual, we can leave unsettled at least for the present, but on the point that for an understanding of its vital activities we must consider both the past and the future of the organism there should be no difference of opinion. When in an embryo there is formed an eye long before it can function, when we see the germcells segregated early and slowly coming to maturity, when we watch the mother-bird building a nest for eggs that are not yet laid, we must, if we are to understand these actions at all, take into consideration their essential reference to the future. When we see in the development of the frog the reproduction of stages passed through by its ancestors near and remote, the formation and destruction of organs which had significance in some distant past and now have none, when we see the mature eel setting forth on its dangerous journey to spawn thousands of miles away in the depths of the Atlantic, we must in accounting for these facts bear in mind their essential relation to the past history of the race; they can be understood only on the hypothesis that in some way or other the past of the organism and of its ancestors still influences its present activities.
1 A striking example of ‘prospective reference’ is afforded by certain types of cleavage, especially in teloblastic division. ‘In all such cases’, writes Wilson (1925, p. 1005), *we cannot comprehend the specific forms of cleavage without reference to the end-result of the formative process; and the problems here encountered cannot be separated from those of development in the larger sense. The teleological aspect of cleavage thus suggested has been recognized more or less clearly, by many observers; most adequately perhaps by Lillie, who has urged that with this principle in mind "one can thus go over every detail of the cleavage, and knowing the fate of the cells, can explain all the irregularities and peculiarities displayed”. The egg is not merely a cell dividing as best it may under the stress of simple and obviously mechanical conditions. It is “a builder which lays one stone here, another there, each of which is placed with reference to future development” (Lillie)’. On cleavage as ‘reminiscent* of past conditions, see Wilson, p. 1011.
Time then enters as an essential element into our definition of organism. The living thing at any one moment of its history must be regarded as merely a phase of a life-cycle. It is the whole cycle that is the life of the individual, and this cycle is indissolubly linked with previous life-cycles — those of its ancestors right back to the dawn of life. This is what we mean by the continuity of life. And the activities of the organism at any stage of its career can be understood only if they are reintegrated in the individual and the evolutionary life-cycles.
7. There is yet another characteristic to add to our concept of organism before it can be regarded as reasonably complete, and that is a characteristic belonging to the functions and activities themselves. The actions of the organism as a whole, regarded from one point of view, are extremely complex, in that they appear to be compounded of a multitude of actions of lower order. Every behaviouraction of a Metazoon, for example, entails the functioning of a neuro-muscular mechanism of some complexity, which functioning is made up of the activities of the component sensory, nerve, and muscle cells. The activities of the cells might in their turn, it would seem, be analysed into their physico-chemical components. Any action of the whole organism would appear then to be susceptible of analysis to an indefinite degree — and this is in general the aim of the physiologist, to analyse, to decompose into their elementary processes the broad activities and functions of the organism.
But it is obvious that by such a procedure something is lost, for the action of the whole has a certain unifiedness and completeness which is left out of account in the process of analysis (see above, pp. 145-9). This unifiedness of response can best be illustrated by reference to one’s own experience of living — one’s actions for example in playing tennis are unified responses of one’s whole physical and mental being at the time, and an analysis of them into their constituents would inevitably miss out the essential point, namely their accurate co-ordination and applicability to the situation arising. In our conception of the organism we must then take account of the unifiedness and wholeness of its activities. This is the more necessary since we have seen that the activities of the organism all have reference to one or other of three great ends, and that both the past and the future enter into their determination. Such characteristics can belong only to actions possessing a concrete reality which is not wholly exhausted by analysis into constituent elements or parts.
If this view be accepted, it follows that the activities of the organism as a whole are to be regarded as of a different order from physico-chemical reactions, both in themselves and for the purposes of our understanding. The relation of the whole-action of the organism to the processes underlying it and to purely physico-chemical action will be considered in more detail at a later stage in this discussion. Meantime we shall add to our definition of organism that the actions of the whole have a unique character and unity which renders them irreducible to processes of lower order. We may here recall our law of biological method that the whole cannot be completely explained in terms of its parts (p. 147 above).
It follows from this proposition that in so studying the responses of living things we do not regard them as purely physico-chemical; we are in fact precluded from treating them as being wholly such. Our definition of whole-action is sufficiently wide and general to cover actions which by common consent are called psycho-physical — as for instance the behaviour of man and the higher animals. We shall see later that in many respects, though not in all, the ‘organic* activities of living things — those manifested through growth and differentiation — resemble behaviour-actions.
We have now sketched, in the very broadest outline, a conception of organism which is completely free from any mechanistic assumption, and seems on the face of it to fit the main facts reasonably well. Let us summarize our conclusions. We agree that biology is essentially the study of individual living organisms, that the individual organism, whether unicellular or multicellular, is the unit to which all biological concepts and laws must relate. The organism is essentially a continuing unity, and all its activities are directed towards the ends of development, maintenance, and reproduction ; these have reference to the future and to the past of the organism, and cannot be understood unless these temporal relations are taken into account ; its activities have a certain unifiedness and wholeness which makes them irreducible to processes of lower order ; the action of the organism as a whole is therefore not completely explicable in terms of the actions of the parts, and still less in terms of physical and chemical action.
On these principles, which appear to be consonant with the broad facts of observation, it is clearly possible to build up a biology free from the materialistic limitations which have hampered its development hitherto.
8. There are several ways of arriving at the principles of an autonomous biology similar to those which we have just outlined. There is first of all the way we have taken here — to start from conceptions which are tacitly followed by most biologists (I except biochemists!) in the practical conduct of their researches, and, accepting the broad facts of observation at their face value, to generalize these without paying much attention to ultimate questions of philosophy. We acquire thus a provisional concept of the organism which gives us certain principles for biology, the final test of which must lie in their success or failure in practice.
The conception of the organism as essentially a unified whole is of course a very old one. It was clearly stated by Aristotle, and Kant has formulated it at great length in the Critique of Judgment. Coming to modern times, Driesch has developed the idea fully in his Ordnungslehre (1912, 2nd edit., 1923), and has added the new category of ‘Individuality* or ‘Wholeness* to the Kantian list. Ungerer has applied the conception in the botanical field in his book Die Regulationen der PJlanzen (1919, 2nd edit., 1926). Many other references might be given. 1
A fruitful line of advance has been that taken by Dr. J. S. Haldane, who has clearly distinguished the concepts of mechanism, organism, and personality — starting out, one imagines, from a Hegelian point of view — and has applied the methods of his ‘New Physiology’ with great success in his classical studies on respiration. 2 The following quotations may give a sufficiently good idea of his views.
‘The fundamental facts with regard to life do not fit into the conceptions by means of which we at present interpret inorganic phenomena. Life is something which the biologist as such must treat as a primary reality, and no mere artefact. . . . The ground hypothesis or conception is that each detail of organic structure, composition, and activity is a manifestation or expression of the life of the organism regarded as a separate and persistent whole’ (1917, p. 100).
Conscious personality is, however, more than organism and requires for its study other concepts than the purely biological; there is accordingly a hierarchy of concepts from the psychological down through the biological to the physicochemical.
‘Although a man is a person and not a mere organism, we cannot trace personality throughout all, or nearly all, of what we observe in a man. To interpret the details as best we can, we have to fall back on the conception of life in the biological sense, just as in details of what we observe in connection with living organisms we have to fall back on ordinary physical and chemical interpretations’ (ibid., p. 115).
1 See particularly H. Hoffding, Der Totalitatsbegriff , Leipzig, 1917, and Erkennt nistbeorie und Lebensauffassung , Leipzig, 1926. Also C. G. Joh. Petersen, 4 On Some Biological Principles’, Kgl. Danske Vidensk. Selskab , Biol. Meddel. , vii. 2, Copenhagen, 1928.
2 Mechanism , Life and Personality , London, 1913; Organism and Environment as illustrated by the Physiology of Breathing , New Haven, 1917; The New Physiology , London, 1919; ‘The Relations between Biology and Psychology’, Aristotelian Soc., Suppl. vol., 1923, pp. 56—75 ; ‘The Fundamental Conceptions of Biology*, Brit. Med . Journ ., March 3rd, 1923; 7 be Sciences and Philosophy (Gifford Lectures, 1 927-8), London, 1929.
Haldane lays great stress on the importance of normality in the environment, both external and internal. His attitude is essentially that of a physiologist freed from the mechanistic trammels. His views are very similar to those developed here, but they differ in some important respects, notably in the more definite separation of psychology from biology; organic activities are in his view uninfluenced by past experience, and the organism is moved merely by ‘blind immediacy’.
Haldane’s ‘biological’ conception of living things is beginning to exercise a considerable influence on physiological thinking. Thus Pcmbrey fully accepts Haldane’s position when he writes:
‘The physiological unit is the living organism, whether it is a single cell, such as an amoeba, or a complex of millions of cells, such as a man. Physiology deals with living processes which cannot be described in anatomical terms, or even in the terms of chemistry and physics: it is a branch of biology, and must be described in biological language. The most important influence in the return to biological conceptions in physiology in this country has been the work and teaching of Haldane.’ 1
The importance from the physiological standpoint of keeping the organism as a whole in view has been emphasized also by C. G. Douglas in his address to the Physiology Section of the British Association in 1927. 2 ‘The more we examine the normal behaviour of the body’, he writes, ‘the more is it brought home to us that the maintenance of the natural life and integrity of the organism depends on the closest coordination of all its different parts; all the organs are interdependent, and can have no real existence save as active components of a corporate whole’ (p. 846). Accordingly, ‘in physiology the organism as such, be it man or one of the lower animals, is our unit, and whatever methods we may employ in our investigations, we must keep that essential fact before us’ (p. 846). Or again, ‘Unless we deliberately study the normal organism in its entirety, I do not see how we can gain any adequate conception about what is really implied by life’ (p. 846).
1 M. S. Pembrey, ‘Physiology’, in Evolution in the Light of Modern Knowledge , London, 1925, p. 264.
‘The Development of Human Physiology’, Nature , Dec. 10, 1927. See also C. Lovatt Evans’s address to the Physiology Section, Brit. Assoc., 1928.
In 1919 the American zoologist W. E. Ritter published an important book 1 contrasting the ‘organismal’ with the ‘elemental’ theory of the organism — a distinction corresponding almost exactly with that drawn in our last chapter between the unity or organismal and the particulate view. The word ‘organismal’ I have in fact borrowed from Ritter. He subjects the elementalist conception of the organism to very complete and penetrating criticism, particularly in its relation to the theory of development, and in its place he puts the view that the organism as a whole, considered as organism and not as mere mechanism, is the fundamental concept in biology to which all others must be subordinated. His central idea is that ‘The organism in its totality is as essential to an explanation of the elements as its elements are to an explanation of the organism’ (i, p. 24). The organism ‘taken alive and whole’ is the primary unit for biology; ‘living substance’ is a myth, for ‘All the living substance that has existed on this earth or anywhere else has existed through and in and because of individual living beings’ (i, p. 115). A separate function or part-process, e.g. a reflex act, cannot be understood save ‘by considering it in the light of the organism’s entire complex of normal activities ; i.e., in accordance with the conception of the organism as a whole’ (ii, p. 184).
Ritter’s organismal conception of the living thing implies no dualistic vitalism :
‘Ideas, or psychoids, or entelechies, or “principles” of any kind conceived as independent of, or even separable from, sensible objects are quite as repugnant to me, an organismalist, as they are to any elementalist. The essence of my contention is that the natural substitute for these imponderable things are the living , individual organisms themselves , and not the particles of which they are composed.
1 The Unity of the Organism , or the Organismal Conception of Life , 2 vols., Boston, 1919. See also Ritter and Baily, The Organismal Conception. Its Place in Science and its Bearing on Philosophy’, Umv, California Public . Zool. y xxx, pp. 307-58, 1928.
Each and every individual organism is a natural reality by exactly the same criteria that the atoms, molecules, cells, and tissues of which it is composed are natural realities’ (ii, p. 149).
The organism is then a natural unity manifesting activities sui generis, which are of a different order from those manifested by inorganic objects. We cannot draw a hard and fast distinction between those of an organism’s activities that appear to be ‘physical 5 and such as appear to be ‘psychical 5 — all should be regarded as ‘vital 5 or ‘organic 5 .
‘If in all the world there is such a thing as objective truth, what we start with and have ever to deal with in studying psychic phenomena, just as in studying all other phenomena of animals, are individual objects or bodies of very particular construction and activity. And by no possibility can consistent thought and statement avoid acknowledging that that vast assemblage of acts and other manifestations which are called psychical are yet only part and parcel of the still vaster assemblage of acts and manifestations presented by the very same living objects, that is, by organisms. Our occupation will be basally with an object , some particular organism, having innumerable attributes, which being classified fall rather roughly into two great groups, one of which we name physical or material and the other psychical or spiritual. . . . Our discussion, then, will never lose sight of the fact that the acts with which wc deal are acts of the organism and not of any of its parts merely, whether these be conceived as material or psychical. No matter how far particular acts may be dependent upon, and so explicable by, particular parts, this dependence cannot in reality be the whole story, for the sufficient reason that the parts are, finally, non-existent except as derivatives of and dependencies upon the organism’ (ii, p. 215).
It will be seen that Ritter’s point of view is essentially the same as that taken here, though he has arrived at it by a different route. I take this opportunity of acknowledging my indebtedness to Ritter, though I read his book at a comparatively late stage in the development of the ideas set forth in this volume.
My own line of approach, if the personal note may be permitted, was from a position of ‘methodological vitalism 5 (1911) in which I questioned the adequacy of mechanistic explanations to cope with the problem of the ‘composition and co-ordination of organic activities, through a phase of psychobiology, in which I emphasized the importance of the psychical aspect of living things, pointing out that even ‘organic’ activities such as growth-responses had many of the objective characteristics of behaviour-action, to my present position, in which psychological notions play a less prominent part (see below, pp. 190-2). For the sake of completeness a short account of the psychobiological point of view, as I developed it, 1 may be given here. The line of attack consists in starting out from the facts of immediate experience — unifiedness of personality, undividedness of the perception-response relation — and arguing that some measure at least of such essentially psychological unity must pervade all the activities of living things. It follows from these premises that the concept of organism cannot be based on physico-chemical mechanism, but must necessarily take account of the psychophysical unity or individuality of living things. A few quotations in illustration of the psychobiological point of view may perhaps be allowed me.
‘Vital activity is a thing which though directly experienced by each one of us cannot be fully conceptualized or explained by analogy with any other form of activity. We know it best and most intimately under the form of behaviour — of muscular action expressing conation and guided by perception — but there is no reason to suppose that it differs essentially in its less explicit, less conscious modes. In any case, our own experience is the only standard and exemplar of vital activity that we have, and we must, whether we will or no, conceive all other psychical or vital activity upon this model’ (1924, pp. 61-2).
‘The relation — perception, horm£, response — is unique and fundamental, and cannot be translated into terms of another order. The living thing is not a machine, for it shows persistent and prospective tendency or striving, and its responses are adjustable to a wide range of circumstances. It is not a mechanism actuated by a psyche, for this formulation simply pushes the mystery further back, by ascribing to an immaterial agent or element of nature the faculties and powers of the organism as a whole. The living thing is not the clay moulded by the potter, nor the harp played upon by the musician. It is the clay modelling itself, or as Aristotle puts it in a beautiful figure, being moulded directly by Nature herself, without the aid of tools “but, as it were, with her own hands” ’ (ibid., pp. 60-1).
1 ‘Psychobiology’, Proc . Aristotelian Soc., 1922-3, pp. 141-56; ‘The Relations between Biology and Psychology’, Aristot. Soc.> Suppl. vol., 1923, pp. 76-85; The Study of Living Things , London, 1924. For another presentation of the psychobiological point of view, sec A. Wagner, Vorlesungen fiber Tier - und Pfianzenkunde , Leipzig, 1912. Das Zweckgesetz in der Natur , Miinchen und Leipzig, 1923, and Die Vernunft der Pflanzen, Dresden, 1925. Also W. Mackenzie, Alle Fonti della Vita Genoa, 1912.
We shall see more clearly later that the concept of organism which we are working out here does include essential elements derived from the psychobiological view.
Another line of thought which converges in practice to similar conclusions regarding the method of studying living things, and opens up the possibility of an autonomous biology freed from at least some of the mechanistic assumptions, is the doctrine of emergence, which has been developed from the philosophical side particularly by Professor S. Alexander, 1 and in its application to biology expecially by Professor C. Lloyd Morgan. 2
9. For our special purpose here — the elaboration of a concept of organism adapted to the study of development — the most valuable philosophical contribution of recent years is, however, that made by Professor A. N. Whitehead, in a series of important books, 3 particularly in his Science and the Modern World. He propounds in the book referred to a theory of ‘organic mechanism’ which is of the highest interest and importance for biology. The doctrine which he maintains is, ‘that the whole concept of materialism only applies to very abstract entities, the products of logical discernment. The concrete enduring entities are organisms, so that the plan of the whole influences the very characters of the various subordinate organisms which enter into it. In the case of an animal, the mental states enter into the plan of the total organism and thus modify the plans of the successive subordinate organisms until the ultimate smallest organisms, such as electrons, are reached. Thus an electron within a living body is different from an electron outside it, by reason of the plan of the body. The electron blindly runs either within or without the body; but it runs within the body in accordance with its characters within the body; that is to say, in accordance with the general plan of the body, and this plan includes the mental state. But the principle of modification is perfectly general throughout nature, and represents no property peculiar to living bodies’ (1927, pp. 98-9).
1 Space, Time and Deity , 2 vols., 2nd edit., London, 1928.
2 Emergent Evolution , London, 1923; Life, Mind and Spirit , London, 1926; ‘Biology’ in Evolution in the Light of Modern Knowledge , London, 1925; ‘A Concept of the Organism, Emergent and Resultant’, Aristot . Soc. Proc., 1926-7, pp. 144-76. See also C. D. Broad, The Mind and its Place in Nature , 1925, and Symposium (E. S. Russell, C. R. Morris, and W. Leslie Mackenzie) on the Notion of Emergence, Aristou Soc., Suppl. vol., 1926.
General Smuts’s well-known book Holism and Evolution (London, 1926) develops generally this same conception of the emergence of ‘wholes’ in cosmic evolution.
3 An Enquiry concerning the Principles of Natural Knowledge , Cambridge, 1919; The Concept of Nature , Cambridge, 1920; Science and the Modern World , Cambridge, 1926, New Impression, 1927; Process and Reality , 1929.
Whitehead bases his whole philosophy of nature on the concept of organism, as being much more concrete than the abstract ideas of matter and mind, and he defines it in such a wide way as to make it apply to all unities in nature, from the living thing down to the electron. He regards their modes of action as not being mechanically determined in the sense of the classical materialism, and he allows for mental states as influencing the general ‘plan’ of the living organism. This conception of organism is developed from a standpoint which is practically the same as that from which the psychobiologist sets out, for individual living experience is taken to be the ultimate standard of reality.
‘In this sketch of an analysis more concrete than that of the scientific scheme of thought’, he writes, ‘I have started from our own psychological field, as it stands for our cognition. I take it for what it claims to be: the self-knowledge of our bodily event. I mean the total event, and not the inspection of the details of the body. This self-knowledge discloses a prehensive unification of modal presences of entities beyond itself. I generalize by the use of the principle that this total bodily event is on the same level as all other events, except for an unusual complexity and stability of inherent pattern. The strength of the theory of materialistic mechanism has been the demand, that no arbitrary breaks be introduced into nature, to eke out the collapse of an explanation. I accept this principle. But if you start from the immediate facts of our psychological experience, as surely an empiricist should begin, you are at once led to the organic conception of nature* (ibid., pp. 91-2).
This quotation may not be altogether clear without a knowledge of Whitehead’s nomenclature, but the general purport is perfectly plain. He turns the tables completely on the materialist, and instead of attempting to explain nature from below upwards, with the help of a few highly abstract concepts, he takes the problem by the other end and generalizes the concrete idea of organism, as given in immediate experience, so that it applies right down the scale, from the organic to the inorganic in its minutest details. All unities that we meet with in the world of nature are organisms, albeit of different degree. ‘The character of existent reality is composed of organisms enduring through the flux of things. The low type of organisms have achieved a selfidentity dominating their whole physical life. Electrons, molecules, crystals, belong to this type. They exhibit a massive and complete sameness. In the higher types, where life appears, there is greater complexity’ (pp. 250-1). This doctrine of a hierarchy of ‘organisms’ is, as we shall see, of great assistance to us in understanding the relation to the whole of the various subordinate individualities in the living body, and the relation generally of physico-chemical action to organic activity.
It follows on Whitehead’s view that the inorganic world, as it is presented to our senses, is for the most part a series of aggregates of the lower (‘inorganic’) organisms, and ‘the characteristic laws of inorganic matter are mainly the statistical averages resulting from confused aggregates. So far are they from throwing light on the ultimate nature of things, that they blur and obliterate the individual characters of the individual organisms. If we wish to throw light upon the facts relating to organisms, we must study either the individual molecules and electrons, or the individual living beings. In between we find comparative confusion’ (p. 139). The theory of evolution in particular forces the organic conception of nature upon us.
‘Evolution, on the materialistic theory, is reduced to the role of being another word for the description of the changes of the external relations between portions of matter. There is nothing to evolve, because one set of external relations is as good as any other set of external relations. There can merely be change, purposeless and unprogressive. But the whole point of the modern doctrine is the evolution of the complex organisms from antecedent states of less complex organisms. The doctrine thus cries aloud for a conception of organism as fundamental for nature. It also requires an underlying activity — a substantial activity — expressing itself in individual embodiments, and evolving in achievements of organism. The organism is a unit of emergent value, a real fusion of the characters of eternal objects, emerging for its own sake. Thus in the process of analysing the character of nature in itself, we find that the emergence of organisms depends on a selective activity which is akin to purpose. The point is that the enduring organisms are now the outcome of evolution; and that, beyond these organisms, there is nothing else that endures. On the materialistic theory, there is material — such as matter or electricity — which endures. On the organic theory, the only endurances are structures of activity, and the structures are evolved 5 (p. 135).
10. In our general sketch of a conception of the living organism which should be the basis of a new biology freed from the materialistic assumptions, we did not probe very deeply into the relations between the activity of the organism as a whole, or the activities of its parts, and the physicochemical processes which in some way form the basis or foundation of vital activity in general. It is necessary now to consider this point in more detail.
The problem has always been a difficult one for any theory of an autonomous biology. So long as one is dealing with living unities as independent wholes, the position is clear enough and the principles we have worked out above can be applied. But when or if one attempts to analyse the activities of a vital unity into its constituent elements, one is immediately brought up against (1) the problem of the relation of the parts to the whole, and (2) the more general problem of the relation of vital activity to physico-chemical process. The first we have partially discussed in the preceding chapter and it will occupy us again in the chapters which follow. As regards the more general problem, we saw reason above to conclude that vital activities could not be completely analysed into their physico-chemical constituents, that in the process of analysis something is dropped out and the essential unity of organic action left unexplained. This conclusion remains perfectly valid, but the general question requires further consideration. What for instance should be the relation between the results of our proposed organismal method and those of biochemistry ? The biochemist frankly treats the living thing in its physico-chemical aspect only, but his method is a perfectly legitimate and fruitful one. We must try to connect up the organismal method with the biochemical in some rational way.
The danger for biology here has always been to fall into a dualism of the physical and the psychical, of means and agent, of mechanism and entelechy. If, when the activities of the organic unity are analysed into physico-chemical part-processes, there is always something left unaccounted for, some ‘surd’ element, one is very apt to hypostatize this into an active agent of some kind — an entelechy, a psychical factor, or the like — which in some way uses and modifies the physicochemical processes of the organism, just as in synthesizing a new compound the chemist intervenes to regulate the reactions in view of the desired end. But such a conception is clearly inadmissible ; it is arrived at by abstracting from the living unity those properties that distinguish it from an inorganic aggregate, and investing these properties with a hypothetical entity on which is thrown the onus of organizing physico-chemical processes into vital actions . 1 It leads to an irremediable dualism.
The real solution of the problem is, I think, that given us by Whitehead. If, as he maintains, the materialistic conception is an abstraction applicable to Nature only under severe limitations ; if the real elements in Nature are organisms of various degrees, from the living thing down to the atom ; if their modes of action are never purely mechanical in the sense of the classical materialism ; then the apparent dualisms which have continually troubled the philosophical biologist disappear — dualism of mind and matter, of the ‘vital principle’ and physico-chemical processes — and we have instead the more manageable problem of the relations to one another of the different grades of ‘organisms’ forming the hierarchy of Nature. Of these, living things are clearly marked off by their special modes of activity, and of this activity we cannot say that it is either physical or psychical — it is distinctively ‘vital’ or ‘organic ’. 1
x Cf. the similar train of thought which leads to the postulation of the ‘materialistic entelechy’, the germ-plasm.
Living things are, clearly, to use Whitehead’s phrase, ‘organisms of organisms’. They are compounded of separate organs, which have a certain degree of independence but are bent essentially on the service of the whole; the organs are composed of cells, which may have a considerable measure of functional autonomy, and might rank therefore as organisms of the second degree . 2 The cells in their turn have organs, or distinguishable parts different as to function, and these, though no longer capable of independent life and no longer showing the full range of vital activities, have definite functional capabilities not shared by units of lower degree; the nucleus, for example, has in situ powers of assimilation and growth; we might recognize therefore as ‘organisms’ of the third degree such semi-independent intra-cellular units as the nucleus and its parts, Golgi bodies, plastids, mitochondria and the like . 3 Below these organized and visible units there come the various grades of ‘inorganic’ organisms, as crystals, molecules, atoms, and electrons. The point is that there is nowhere an absolute break, there is no absolute division between the organic and the inorganic, nor between actions into which ‘mind’ enters and actions which are purely ‘physical’. And for us the continuity must be regarded as one from above downwards ; it is impossible to explain the modes of action of any one grade of unities by the modes of action of any lower grade; on the contrary, something of the character of the higher grades, as it were, filters down and colours the action of even the lowest grades. It is important to note that the sub-organismal units are organized and arranged so as to form the individual living thing, which is made of them plus their ‘composition’, to use Aristotle’s term. For this, if for no other reason, it is impossible fully to explain the global activity of the whole in terms of the activities of its subordinate and necessarily abstract unities.
1 It is this characteristic of the activity of living things which we have attempted to express hitherto by using the somewhat misleading word ‘psycho-physical* (see above, p. 139).
2 How far the cell may be regarded as an independent unity will be discussed in Chapters XI-XII.
3 One must bear in mind that all these subordinate organic ‘unities* are to a large extent abstractions.
On a previous occasion 1 I proposed a classification of vital phenomena into responses, functions, and material conditions, including the physico-chemical properties of living matter. My ‘responses’ were the activities of the organism as a whole, ‘functions’ the activities of the parts, and ‘properties’ the action of the physico-chemical constituents of the organism. This classification requires very little modification to fit the organic conception of things which we have taken over from Whitehead. Generalizing the classification, I should prefer to speak now of the modes of action of unities of different degree — instead of ‘responses’ to speak of ‘modes of action of the organism as a whole’, instead of ‘function’ to speak of ‘modes of action of organs and cells’. I should insert a separate category of modes of action of intra-cellular units, and for convenience keep the old terms of properties and material conditions, these being re-defined as the modes of action of inorganic unities within and without the organism, respectively.
It is not proposed at this stage of the discussion to enter into an analysis of the actual relations between the different grades of unities concerned in the functioning of the living organism; this will occupy our attention in the succeeding chapters. But, as we have already seen, one thing is abundantly clear — that the modes of action of lower unities do not ‘cause’ or fully account for the modes of action of higher ; their role is rather to condition these higher modes, both to limit them and to render them possible.
To take a few simple illustrations — a frog or a bird cannot
1 Study of Living Things , 1924, pp. 100 ff. chapter (XIV, pp. 279-83) that the chromosomes, for example, may condition and modify the developmental pro parts, and physico-chemical processes) and to the main ends of the organism (development, maintenance, and reproduction). Bio-chemistry continues downward the study of the conditioning factors, and the two methods dovetail into each other.
On the other hand, at the opposite end of the scale, organismal biology merges easily into comparative psychology, so soon as the modes of action of the whole reach such a level as to give clear evidence of having reference to a perceived environment, when the organism must be regarded not merely as organism, but as percipient organism. Such is the case certainly with the higher insects and vertebrates and probably also much farther down the scale of beings. Organismal biology therefore appears to fit comfortably in between the psychological sciences on the one hand and the physical on the other.
1 2 . It follows from our definition of the aims of organismal biology that its primary task is to study the modes of action of organic unities; it must not seek to resolve them completely into modes of action appertaining to unities of lower degree, though it may and should study these lower unities in their aspect of conditioning, co-operating and modifying factors. It must then deal with the fundamental functions of living individuals as its irreducible elements of explanation, and not seek to compound these out of properties belonging to unities of lower order. It will accordingly work with, and in terms of, such biological functions as assimilation, respiration, excretion, growth, differentiation, mnemic retention, perception (if the facts demand it), and response, as its fundamental elements, and will eschew the attempt to analyse these into their constituent part-processes, leaving this task to the bio-chemists.
Organismal biology will accordingly require a whole set of concepts and methods, different from those which are current in the physical sciences, and in part analogous to those employed in psychology. Its concepts must have reference to the individual organism, and not at all to abstractions like ‘living substance’, the ‘organic machine’, or hypothetical entities like biophors : they must be able to take account of the forward-looking and backward-looking aspects of vital activities. All its laws must be stated in terms of organic unities, regarded as individuals persisting in time, whose activities are related both to the past and to the future.
Many of the necessary concepts we shall find already in use by biologists, especially of the older and sounder tradition, but they require for the most part accurate re-statement, and freeing from any tinge of materialism that may still cling to them. Certain general concepts which are often rather loosely used, such as ‘function’, ‘cause’, ‘potentiality’, ‘conditioning’, ‘determining’, will also require careful analysis and definition. We shall not attempt the task here. 1
13. We cannot claim for organismal biology anything like complete adequacy, or a close approach to full understanding of the living thing. The full secret of life will always elude a purely scientific treatment ; it may be experienced, imagined, and felt, but never completely pinned down and explained. Something will always escape definition and measurement. Nevertheless we may rightly claim that the organismal method gives us a biology less remote from the truth than the abstract and schematic account to which the materialistic assumptions would limit us. It gives us a unitary biology, in which the abstractness and excessive analysis of the materialistic method are avoided ; it allows us to look upon the living thing as a functional unity, disregarding the separation of matter and mind, and to realize how all its activities — activities of the whole, and activities of the parts, right down to intra-cellular unities — subserve in co-operation with one another the primary ends of development, maintenance, and reproduction.
In the materialistic scheme there is no room for such concepts. Mechanism with its unrestrained use of the method of analytical abstraction means the disintegration of the organism into a concatenation of processes of lower order, to the arrangement and collaboration of which, to their orderliness in space and time, it can supply no key. Such analysis leaves always an unknown surd, which is hypostatized as an entelechy or as a materialistic ‘controlling’ agent, such as the germ-plasm. The mechanistic method can study only the conditions of vital functioning; the specifically organic modes of action of the higher unities, cells and organisms, dissolve away in its hands into a tangle of physico-chemical processes. The organismal method, on the other hand, accepts the fact of unity and does not try to analyse organic activity completely into factors of lower order. It regards the organism not as purely material, in the sense of being merely a structural configuration, nor as a body plus a soul or entelechy, but as a unity sui generis , having ways of action which are not fully explicable in terms of mechanism, nor for the most part in terms of psychology, which are therefore distinctively ‘organic’.
1 Valuable work has been done in this direction by J. H. Woodgcr, in his Biological Principles , London, 1929.
14. A word as to the relation of the organismal to the psychobiological point of view, which is based upon a particular philosophy. From the standpoint of psychobiology the organism is regarded as a monad, somewhat in Leibniz’s sense, and its modes of action as being essentially of the same nature as the perception-response relation which is characteristic of conscious behaviour. This point of view certainly emphasizes one factor which it is important to realize in the formulation of the organismal method, namely that the concept of organism in the functional sense is in the long run derived from an analogy with our own conscious life as experienced. Only in immediate experience have we direct knowledge of what a living organism is, and any adequate concept of individuality, of organism, which we may form must ultimately draw upon this experience, and have reference to this experience, as the ultimate standard. The psychobiological point of view is certainly applicable to the study of animal behaviour — of response to a sensed environment by means of bodily movement — and it opens up the possibility of tracing out through the animal kingdom the evolution of the separate worlds of perception in which as monads all animals live distinct from one another, each mirroring its own little corner of the universe and attending to such elements in it as are important for its welfare. It is applicable in all cases where the organism must be regarded as percipient. Whether and how far the psychobiological point of view may be profitably extended to the study of such activities as metabolism, growth, differentiation, and the like, is much more doubtful, and can only be decided by trial. 1 Clearly one must not apply psychological concepts unless the facts absolutely demand them, but on the other hand their use must not be excluded. One must remember that there are other forms of perception besides the perception of external relations — interoceptive perception, for example. It may be that growth- responses, such as the regeneration of lost parts, which take place under the control of the organism as a whole are mediated by interoceptive sensations. Wherever perception enters, be it even in rudimentary form, a psychobiological interpretation is called for.
It may be well to emphasize again the point that from the organismal standpoint there is no separation of vital activities into ‘physical’ and ‘psychical’ — all are organic. All actions of the organism as a whole show certain characteristics — unity, reference to past and future, adaptability — whether they are behaviour-actions or growth-actions. They must be treated then as irreducible to processes of lower order. Of these actions, a certain class require for their adequate interpretation the assumption that the organism performing them is percipient : such actions demand therefore a psychobiological interpretation, employing concepts borrowed from psychology. These are in general behaviour-actions, but the possibility must not be absolutely excluded that morphogenetic activities also may in some cases require a psychobiological interpretation.
In connexion with this question of applying psychological concepts to biological facts, it is worth while remembering that the existence of consciousness in other organisms is always a matter of inference, and is not susceptible of proof. But the point is really irrelevant. In judging whether such and such actions are ‘psychological’, we consider whether they belong to the general type of actions known to us in immediate experience as psychical, but which even in experience are not always or necessarily conscious. We cannot use ‘consciousness’ as an explanation in biology.
1 I tried to make clear even in my Study of Living Things that ‘once we leave the domain of animal behaviour, psychology is not going to help us in the study of organic responses*, but this point has been generally missed even by sympathetic and understanding readers.
15. In conclusion, it may be useful to apply in a preliminary way the ideas we have worked out above to the problems of development and heredity which were briefly characterized in Chapter I. In the succeeding chapters of this book certain of these applications will be considered in more detail, though no attempt will be made to work out a complete theory of development on organismal lines. For this the time is not yet ripe ; all that can be done at present is to indicate some obvious lines of attack upon these problems.
The biological principles which we have provisionally adopted can be used (1) for criticism, and (2) for construction. Employed as an instrument of criticism, they enable us to make a clean sweep of certain ideas regarding development and heredity which general acceptance has rendered almost sacrosanct, namely the germ-plasm theory in all its forms, including all theories of representative particles and all theories relying upon the configuration idea. We shall reject a limine all particulate theories of development.
If we hold fast to the principle that the whole cannot be completely explained in terms of its parts, that the modes of action of higher unities may be conditioned, but cannot be fully accounted for, by the modes of action of lower unities, it follows that no substance and no sub-cellular unities can be invoked as sufficiently accounting for the phenomena of development and heredity, which are essentially phenomena manifested by whole organisms — unicellular or multicellular. The connecting link between one generation and the next is in general the cell. Now the cell is unique in that it can be either a whole organism or a constituent of a higher organism — a peculiarity not shared by any sub-cellular unit. Hence the lowest common measure of development and heredity, the lowest unity in terms of whose modes of action the problems may be rationally stated at all is the cell-organism. Sub-cellular units such as chromosomes or chromomeres may have their importance as conditioning development and heredity within organismal unities, and there may even be direct transmission of special substances from cell to cell, but it is fundamentally wrong in method to ascribe either to such substances or to such sub-cellular units (and d fortiori to abstract and hypothetical units like genes or biophors) the essential determination of the phenomena of development and heredity, or to attempt to explain these phenomena of organisms in terms of sub-organismal units. The modes of action of the organism can be developed and displayed only by the organism as a whole, and they can be transmitted only by the new organism which it makes, usually though not invariably in the form of a single cell, carrying in potentia the modes of action of its progenitor. The true germ-plasm must be the cell-organism.
These considerations in themselves are sufficient to eliminate all theories which attempt to explain development and heredity in terms of a specific germinal substance, of a ‘material basis of heredity’, contained within the cell, for these are palpably inadequate to express or explain the facts. The germ-plasm or material basis is a conceptual fiction imposed upon the facts by the exigencies of the mechanistic method. If the germ-plasm disappears there disappear also all representative particles, determinants and genes. All that these concepts were invented to explain can be equally well accounted for by the conditioning action of intra-cellular units such as the chromosomes (see Chapter XIV, pp. 285-7). The purely physico-chemical theories of development also are seen from the organismal point of view to be unequal to the task they attempt, for the simple reason that development cannot possibly be explained in terms of substance, or of physico-chemical system, but only in terms of individual organic unities and their activities.
In considering the phenomena of hereditary transmission from the organismal point of view it will be necessary to analyse carefully the respective parts played by the organism, the cell, the intra-cellular units, and any specific substances that may be involved, for it is already clear that transmission may mean different things when applied to these different objects; there may be a direct physical sharing out of specific substances from cell to cell, or a handing on of specific metabolic processes associated with intra-cellular units such as the chromosomes, or the inheritance of the general developmental potentialities by the cell-organism which we call the fertilized egg. How this last process is to be conceived is indeed one of the deepest and most inscrutable problems that confront the human intellect, and it is far from being solved. This much is however abundantly clear, that the inheritance of the modes of action of the organism as a whole and of its constituent, collaborating parts, must be on a different level altogether from the mere physical transmission of substances or even of the metabolic rhythms of subcellular units. We shall see that the problem of transmission is closely linked up with the general problem of reproduction (see pp. 302-4 below).
With regard to differentiation and to the course of development as a whole, these can no longer be thought of as due to the mysterious determinant action of a hypothetical germinal configuration or of any intra-cellular mechanism whatsoever. Weismann’s attempt to explain development as due to the orderly disintegration of a determinant-complex must be regarded as faulty in conception and useless in practice. We must take the facts as they are, and not invent complexities to account for the baffling simplicity of the process. The future task of organismal biology will be to analyse the facts of development — differentiation, harmony, autonomy, regulation — in terms of the modes of action of the organism as a whole, both as conditioned, and as executed, by the activities of the parts. It will pay much attention to the fundamental fact of differentiation and limitation of function.
It were premature to attempt here to enumerate all the fundamental activities or modes of action of the whole organism, whether unicellular or multicellular, but the more important may be briefly mentioned. There is first of all the group of metabolic functions — assimilation, dissimilation, excretion, respiration, and the like — those that Bichat called the functions of the vegetative life. Closely connected with these are the functions which have to do with the production, maintenance, and restoration of form, both the form of the single cell and the arrangement of differentiated cells to constitute organs and organisms. These may be called the morphogenetic or morphoplastic functions, and are of special importance in the study of development. A third great group comprises those associated with the behaviour of the organism in relation to its external environment and to its own body; they include on the one hand sensory perception in its different forms — extero-, intero-, and proprioreception — and on the other hand responses of various kinds. Other fundamental capabilities of living things, which apply to or affect the more special functions, are the power of mnemic retention and repetition, and the power of selfregulation so much stressed by Roux. 1
With regard to the problems of heredity and recapitulation, and generally of the historical basis of development, our new principles render possible a line of attack which is closed to the mechanist, but was followed with much success by Samuel Butler. We have seen that the modes of action of the organism as a whole must be construed in relation to the past history both of the individual and of its line of progenitors, and this enables us to envisage the possibility of giving some rational account of the stereotyped repetition of developmental rhythm which shows itself as heredity in the broad sense of the word, and of the reminiscence of ancestral states which we signalize in the law of recapitulation. The mechanist can take no account of this historical aspect of development. The further principle that developmental events have objective reference to a future end enables us to interpret the phenomena of non-functional differentiation and generally all cases of anticipatory action — or at least indicates the line along which such explanation is to be sought. It will probably be found that there is a close relation between past experience and anticipatory action, so that the one may explain the other, through some law of organic habit as yet undiscovered. Looked at from this point of view, the much-debated question of the transmission of acquired characters or of acquired experience takes on a new aspect.
1 It will be noted that our fundamental organic ‘modes of action* correspond roughly with Roux’s ‘complex components’, which were, however, attributes of cells.
In conclusion, and as a preliminary to the fuller discussion of the question which will be undertaken in the remaining chapters, let us consider very briefly the significance of the cell in relation to the organism as a whole and to reproduction. The question is of great importance methodologically, in connexion with the principles of organismal biology, and for this , reason it will be dealt with in some detail in the present book. It is a test case for our thesis that the whole is more than the sum of its parts.
We have seen that in two respects the cell is a specially important unit; first, because it is the lowest unit that is capable of independent life, the simplest type in which the phenomena of life can be fully manifested, and second, because in multicellular organisms reproduction is as a rule carried out through the agency of single cells, which represent in fotentia the whole organism. The egg-cell is therefore a true ‘cell-organism’. One must remember that the fundamental unity with which we deal is the organism, and that it is only when the cell is at the same time an organism that it acquires a particular significance. As a constituent or part of a multicellular organism it has much less importance. According to our principles, we cannot resolve the activities of the whole multicellular organism into the activities of its component cells. As De Bary pointed out long ago, it is the organism that makes the cells, not the cells that make the organism. We shall see in the next chapter that from the point of view of the organism as a whole the cell is mainly a ‘metabolic convenience’, that the association of nuclear and cytoplasmic substance in the size relations characteristic of cells is primarily conditioned by the nature of metabolic processes, and by the relation between the surface and volume of the nucleus. 1 As a necessary condition for metabolism, and therefore for life, the celltype of organization must characterize living things, and it is only when the scale of magnitude required is small that the cell acquires the rank of organism. As a constituent of a multicellular body it has much lower rank and significance. We shall see that the cell-theory has much exaggerated the importance of the cell, and obscured the importance of the organism. In considering the relation of the cell to differentiation we shall see that the egg-cell is essentially not merely a cell, but the organism-to-be, and that segmentation and nuclear division have little to do with differentiation. In the succeeding chapters we shall develop this question of the relations between the organism and its parts (cells, nuclei, chromosomes), and consider the bearing of our conclusions on the general theory of development, heredity, and reproduction.
1 This view of the cell is briefly outlined in J. G. Adami ,7 be Principles of Pathology , vol. i, London, 1908, pp. 37-8. It is implicit in Sachs’s ‘energid’ theory.
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Cite this page: Hill, M.A. (2020, April 6) Embryology Russell1930 10. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Russell1930_10
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