VITALISM
By J. W. Jenkinson
In one of the oldest biological treatises in the world, the soul or life of an organism is defined in the most general way as an activity of a natural organic living body—ἐντελέχεια σώματος φυσικου̑ ὀργανικου̑ δυνάμει ζωὴν ἔχοντος—life being autonomous nutrition and growth and decay. The activity may, however, be latent or patent, passive or active, sleeping or waking, without losing its peculiar characters. It is substance (οὐσία), but substance as ‘form’ as opposed to the material substance of the body, and the living body is therefore also a substance in a double sense.
It is not identical with the body; but as form, proportion (λόγος), activity (ἐνέργεια), essence (τὸ τί ἠν εἰναι), it is related to the body, mere matter (ὕλη), and potentiality (δύναμις) in just the same way as the seal is related to the wax; and the body is the instrument whereby it effects its purposes; though subsequent in time, it is prior in thought to the body, as all activities are to the materials with which they operate.
At the same time neither it nor its parts are separable from the body, with the exception, possibly, of mind (νου̑ς); it is indeed the actual or possible functioning of the body, like the seeing of the eye or the cutting of the axe, and with the disappearance of the capacity of this functioning the soul itself also perishes. Lastly, it is a cause (ἀρχὴ καὶ αἰτία) in a triple sense: first, as the source of motion; secondly, as that for the sake of which the body exists; and thirdly, as its essence (οὐσία) or formal cause. The soul or life is of several kinds, which form together an ascending series each member of which is necessarily involved in those above it.
The lowest is the nutritive soul (θρεπτική), found in all living things, and the only soul possessed by plants. It is defined as motion in respect of nutrition, decay, and growth, processes which involve alteration (ἀλλοίωσις) in the body; and its functions (ἔργα) are to utilize food for the maintenance and reproduction of the form of the body, and to control and limit growth.
The second is the perceptive soul (αἰσθητική), the possession of which distinguishes animals from plants. This also is a kind of alteration (ἀλλοίωσις τίς) and consists in being moved and affected. The fundamental and indispensable perception is touch (ἁφή), for it is concerned in the acquisition of the food. It is invariably present: the others may or may not, some or all, coexist with it.
Thirdly, some animals are possessed of a capacity for locomotion, and the performance of this function requires again a special kind of soul.
Lastly, there is the reasoning soul (διανοητικά) or mind (νου̑ς). This is found in man alone, unless there be other beings similar to him, or even nobler than he. Mind alone is eternal and separable from the body.
Though the observation and experiment of modern science would doubtless find much to alter in the details of these simple definitions, yet it must be conceded that, by what is certainly a most fortunate guess if it is not the most wonderful insight, Aristotle has laid his finger on the cardinal point of modern physiological doctrine. For, putting aside for the moment the mental faculties, it is here laid down in the clearest manner that not only the functions of growth and decay, nutrition, and reproduction, but also the capacity of responding to stimuli are to be ultimately resolved into some kind of movement of the particles of which the body is composed. Life, in short, as we might say with Virchow, is a mode of motion.
The biology of to-day distinguishes living from inanimate bodies by the possession and exercise of the three principal properties or functions of metabolism, irritability, and reproduction; and further, the body which performs these functions is not only composed of chemically complex substances—proteids—which are not found in things that are not alive, but possesses a structure. In no case, even the simplest, is the organism a mere homogeneous lump of protoplasm, but it has parts or organs, visibly different from one another, and obviously correlated with the activities appropriated to each; and it is the preservation of that structure, in the individual and in the race, which is the end towards which the collective performance of all these functions, or the life of the organism, is apparently directed.
Some of these peculiarities are shared by certain things that are not commonly regarded as alive. Crystals have of course a definite structure; they can divide, and when broken they can make good the missing part, but they do not assimilate to the substance of their own bodies a food-material which is less complex than it, and they are not irritable.
The differences, indeed, between the living and the lifeless are so profound, that it is not to be wondered at that there should have been in all ages natural philosophers who have held that living activities are phenomena sui generis, differing toto caelo from the properties exhibited by lifeless bodies, and never by any conceivability to be expressed in terms of these.
This doctrine is vitalism.
It exists in several varieties, but one at least is of very ancient lineage and can be traced back through mediaeval times to the biological speculations of the Greeks.
Whether Aristotle really held the vitalistic views which have since been attributed to him is a matter we shall have to discuss later on, but it is certain that in the writings of Galen there is to be found a theory of life which bears the stamp of Aristotelian influence, and was destined to hand that influence on to future generations. Galen admits the sensitive soul of Aristotle as the peculiarity of animals, and the rational soul for man, but substitutes for the nutritive soul certain works of nature—attraction, repulsion, retention, alteration. And further, the rational soul is no longer immortal, but perishable, and is dependent on the body, where its seat is in the brain; it is material or quasi-material, a πνευ̑μα, most efficient when dry.
After a long interval this doctrine reappears in the sixteenth century in the writings of Vesalius, who tells us that the heart has a vital soul, the liver a natural soul, while there is elaborated in the ventricles of the brain an animal spirit or principal soul.
Meanwhile, however, the conception of life as something material had been discarded by Paracelsus for the belief that the soul, or as he called it, the ‘Archaeus’, by which the chemical processes of the body are governed, is not a material but a spiritual force, a view restated by Stahl more than a hundred years afterwards. ‘The events of the body’, says this author, ‘may be rough-hewn by chemical and physical forces, but the soul will shape them to its own ends, and will do that by its instrument, motion.’
This, of course, is vitalism, and vitalism in its extreme or ‘animistic’ form. The idea recurs later on in the biology of Treviranus. To be living is to have a soul, he tells us, and the conscious Lebenskraft employs the forces of the material world to form the organism. ‘Das Weitzenkorn hat allerdings Bewusstsein dessen, was in ihm ist und aus ihm werden kann, und träumt wirklich davon.’ Though he adds quaintly enough, ‘Sein Bewusstsein und seine Träume mögen dunkel genug sein’. It is curious to observe the revival, at the beginning of the twentieth century, of this mediaeval mysticism in the speculative writings of so accomplished an experimentalist as Hans Driesch.
Driesch is an embryologist who in his earlier days had enunciated an invaluable analytical theory of development, a theory which suggests that while the formation of the first or elementary organs that appear in the embryo or larva—such structures as the larval gut or sense-organ, or the germ-layers—depends upon the presence in the germ of certain specific organ-forming substances (and this is a fact which has since been abundantly demonstrated by experiment), the origin of parts that appear later in development may be accounted for by the action of the first-formed structures upon one another, these actions being in the nature of physiological responses to stimuli; and for this also some evidence has been produced. On this view differentiation is a mechanical process, set in motion by fertilization or some other cause, and, given a certain initial structure of the germ or ovum, given the presence in it of a certain number of parts or substances capable of acting upon one another with a fixed co-ordination or harmony of the stimuli and the responses, given further a proper constitution of the external environment, then a definite result must follow, the production of an organism which is like the parents that gave it birth.
But in his later treatises this hypothesis has been repudiated, and, by a remarkable volte-face, replaced by a dogma of a wholly different kind. For now it is urged that no merely material factors can possibly account either for the harmony of development—the due co-ordination of mutually reacting parts; or for the secondary harmony of composition—the formation of complex organs by the union of tissues; or for the functional harmony seen in the activities of the adult.
For example, it is asserted that any fragment of an egg of a sea-urchin, if not too small (not less than 1/32 of the egg), can give rise to a whole and normal larva. We are told that the cells of the segmented ovum may be disarranged to any extent by various means, such as raising the temperature, diluting the sea-water, removing the calcium from the sea-water, or by shaking, without prejudice to the ultimate normality of development. Each part of the ovum can therefore, according to the needs of the case, give rise to any part of the resulting organism. ‘Jeder Teil kann nach Bedürfniss jedes.’
And thirdly, when the gastrula of a sea-urchin is transversely divided into two, each half, it is stated, develops into a diminished whole larva in which the gut becomes divided into the characteristic three regions, and all the other organs are formed in correct proportion.
For each of these acts of development in the whole uninjured larva an explanation may conceivably be given in terms of formative stimuli exerted by the originally distinct parts of the egg and calling forth responses in other parts. A mechanism may be thought of which, when set in motion, will achieve a certain end in accordance with its own pre-established harmony; but a mechanism which can be subdivided ad libitum, or almost ad libitum, and the parts of which will still achieve the same end, will still behave as wholes with their parts co-ordinated in the same ratio, temporally and spatially! Such a mechanism is inconceivable; for to ensure the uniform result, the relative amounts and positions of the necessary substances must be imagined as identical in every possible fragment of the egg that is not too small. Something is therefore required to superintend, to co-ordinate the causes of development in the case not only of the part but of the whole egg as well; and this something is not material. A corroborative proof of the inadequacy of the purely material explanation—the causal explanation in the ordinary sense of the phrase—may be derived from a consideration of certain other vital processes. The facts of acclimatization and immunity betray an extraordinary adaptability of the organism to a change in its environment; an organ will adapt itself structurally to an alteration, quantitative or qualitative, of function [Roux’s ‘Functional Adaptation’]; lost parts can be regenerated; and then there is the physiology of the nervous system.
In all these cases of ‘regulation’—and indeed in all other responses to stimuli—the same element, inexplicable in chemical and physical terms, exists and must exist in development. This entity is not a form of energy, but a vital constant, analogous to the constants or ultimate conceptions of mechanics and physics and chemistry and crystallography, but not reducible to these, just as these cannot be translated into one another.
Driesch describes it as a rudimentary feeling and willing, a ‘psychoid’, ‘morphaesthetic’ or perceptive of that form which is the desired end towards which it controls and directs all the material elements of differentiation, like the grain of wheat of Treviranus, dreaming dimly of its destiny. It is thus a vera causa—an unconditional and invariable antecedent—a psychical factor which can intervene in the purely physical series of causes and effects, and for it he revives the Aristotelian term ‘Entelechy’.
Such is the ‘vitalism’ introduced by Hans Driesch, a teleological theory clearly, but no mere metaphysical doctrine of final causes: rather a dynamic teleology which not only sees an end in every organic process, but postulates an immaterial entity to guide the merely mechanical forces towards the realization of that end.
Such a theory is open to very serious criticism from both the scientific and the philosophical side. But before we pass to that criticism let us turn aside to examine some of the other aspects under which the Proteus of Vitalism presents himself.
Thus the modern physiologist Bunge, while owning that it would be a lack of intelligence to expect to make with our senses discoveries in living nature of a different order to those revealed to us in inorganic nature, yet insists that we must transfer to the objects of our sensory perception, to the organs, to the tissue elements, and to every minute cell, something which we have acquired from our own consciousness, something, that is to say, which is not motion, and is not in space, but is in time only.
The essence of vitalism, so Bunge would have it, lies in starting from what we know, the internal world, to explain what we do not know, the external world. We can only remark that this position appears to rest upon an epistemological confusion, for Bunge has evidently failed to distinguish between the idealism which teaches that the world of nature, including our own bodies, only exists in so far as it is an object of knowledge, that reality is ultimately ideal, and the ‘animism’ which, as we have seen, gives every object, at least every living object, in nature a directive consciousness of its own. The former does not lie immediately within the scope of the present inquiry; the latter we shall have occasion to discuss again.
How far the tenets of animism are to be attributed to Johannes Müller is not very clear. For while Müller maintained that an organism is due to an idea which regulates its structure, is the cause of its harmony, and is in action in the organism itself, exerting on it a formative power, yet he held that the process was unconscious. Müller indeed distinguished explicitly between the vital and the mental or conscious principle, for in the operations of the former the manifestation of design is the result of necessity, not of choice. At the same time the two resemble one another in being homogeneous, in existing throughout the mass of the organism which they animate, and in being divided together with the organism (as in regeneration) without suffering any diminution or change of their powers.
In this conception of the unconscious idea there may possibly be some confusion between the formal and the final cause, between the idea of the end to be realized, present at the beginning in the mind of the artificer, and the end itself. The former is animism: the latter is sound enough as metaphysics, but is not science at all.
There is still another school of vitalists which, while not going so far as to commit itself to a belief in a ‘psychoid’, yet proclaims in no uncertain voice the autonomy of the organism, and not content with the assertion that at present we have not succeeded in reducing the activities of the organism to chemical, physical, and mechanical processes, maintains the utter futility of such endeavour, and pronounces over the hidden mysteries of life an eternal Ignorabimus.
Some such view as this we must, I think, attribute to Dr. Haldane. ‘In biology’, he says, ‘the phenomena which are or ought to be observed from the very beginning are not physical and chemical phenomena as self-existent events, but these phenomena as expressions of the activity of living organisms. It is the living organism, and not the physical phenomenon, which is the reality for biology.’ His belief in organic autonomy is based on the physiology of metabolism, secretion and absorption, the circulation of the blood, and the nervous system. Thus in discussing the blood, after pointing to the constancy in its volume and composition, he proceeds: ‘Neither starvation nor ingestion of food and drink materially affect it: liquid injected into it is got rid of with remarkable rapidity; and any loss of blood by bleeding is soon replaced. This vital metabolism of the circulatory system is doubtless due chiefly to the activity of its lining endothelium, which most certainly does not play the mere mechanical part which has often been attributed to it. The other so-called “mechanisms” can likewise be shown to have all the characteristics of the living body, inasmuch as they actively maintain their structure, just as the organism as a whole does so. There is thus no warrant for calling them mechanisms, and thus ignoring what is one of their essential characteristics.’ In passages such as these we seem to catch an echo of Müller’s unconscious idea, and again we ask ourselves, Are we dealing with a final or a formal cause? Indeed, Dr. Haldane insists that his ground conception is teleological.
There is still one other vitalistic theory to which we must allude, although its interest is now merely historical. This is the belief in a special vital material, unlike the material of which lifeless bodies are composed, and endowed with a special vital force, different from but co-ordinate with the forces of mechanics and physics.
In his Histoire Générale des Animaux Buffon, after referring to the obvious peculiarities of animals and vegetables—that their actions are directed to an end, the conservation of a durable species—proceeds to elaborate a thesis in which it is held that they are composed of organic germs, and that germs of the same kind are distributed throughout nature, lifeless as well as living. When an animal or plant dies, its body is dissolved into these germs, which are then scattered abroad; when it assimilates, it is by separating these ubiquitous particles from the brute inorganic portion of the food. The former is utilized for its own growth, the latter it gets rid of by evacuation and excretion. Lifeless matter is therefore never converted into living material.
Another advocate of the doctrine of a vital force, a property of the tissues of the body, and at perpetual war with those inorganic forms which tend to their destruction, was the physiologist Bichat, Such a conception as this could not of course survive the rise of modern chemistry. Its death-knell was sounded when Lavoisier and Laplace showed that the bodies of organisms were composed of the same elements as are found in inanimate nature, and it has long since passed into the limbo of discredited speculations.
Apart from this, vitalistic theories would appear to be in the main of two kinds.
First, there is the metaphysical vitalism which tells us we can never explain the living in terms of the lifeless, insists on the permanent separation of the sciences of biology on the one hand from chemistry and physics on the other, and preaches the autonomy of the organism without venturing to tell us in what that autonomy consists.
Secondly, there is the psychological theory of animism which posits an autonomous psychical entity to preside over the chemical and mechanical operations of the body, whether already formed or in process of development, and to direct them towards its own ends, the conservation and reproduction of that body’s specific form.
A third party, halting between two opinions, suggests an unconscious idea, without, however, clearly explaining whether this is to be taken in a metaphysical or a psychological sense. Frankly opposed to vitalism in all its forms is the conception of the living body as a mechanism. This has also an honourable ancestry behind it. How far the biology of Aristotle is to be looked upon as mechanistic we shall presently have to inquire, but in Galen the soul is certainly material, or quasi-material, as we have already observed. It is, however, in the physiology of Descartes that mechanism first appears unmistakably in its modern guise.
For Descartes the body is simply an earthly machine. The nerves are tubes up which—in sensation—the animal spirits flow to the brain only to be reflected (whence our term reflex action) down other tubes to the muscles.
‘All the functions of the body’, he tells us, ‘follow naturally from the sole disposition of its organs, just in the same way that the movements of a clock or other self-acting machine or automaton follow from the arrangement of its weights and wheels. So that there is no reason on account of its functions to conceive that there exists in the body any soul, whether vegetative or sensitive, or any principle of movement other than the blood and its animal spirits agitated by the heat of the fire which burns continually in the heart and does not differ in nature from any of the other fires which are met with in inanimate bodies.’
The rational soul, the soul which thinks, that is, understands, wishes, imagines, remembers, and feels, is not material. Yet it always acts through the machine, though that machine can go on perfectly well without the soul. ‘When the body has all its organs properly arranged for a particular movement it has no need of the soul to carry them out. All movements, even those which we call voluntary, depend principally on the same disposition of the organs. One and the same cause renders the dead body unfit to produce the movements and leads the soul to quit the body.’
The biology of Descartes appears to have been accepted by contemporary physiologists like van Helmont and Borelli, and certainly commended itself to another philosopher of eminence, Leibnitz. Like Descartes, Leibnitz also affirms that the body is a machine or natural automaton; unlike Descartes, however, he refuses to believe that the mind directs the machine in any way. Rather there is a complete series of psychical parallel to a complete series of physical events, and between the two a pre-established harmony.
Although the details of Cartesian physiology have long since been exploded, yet the mechanical principle which that philosophy enunciated so clearly has persisted and has indeed proved to be the rock on which modern physiological science has been built. For, when once the chemists had discovered animal and plant structure to be composed of elements found in lifeless bodies, and had proved that compounds found only in the organism could yet be synthesized in vitro, there was no longer any reason why the properties of the compounds should be considered as of a different order to the properties of their component elements. A method applicable to one was applicable to the other, and as Claude Bernard has put it, mechanical, physical, and chemical forces are the only effective agents in the living body, and they are the only agencies of which the physiologist has to take account.
The substances of which the living body is made up are no doubt extremely complex, yet none the less—to quote a more recent writer, Verworn—‘physiology is in the last resort the chemistry of the proteids’. This is the principle that has now for nearly a century guided and stimulated research into the functions of the organism: to this principle physiologists, too numerous to name, have not been ashamed to subscribe: under its banner some of the proudest triumphs of the science have been won. Yet it is precisely this which modern or neo-vitalism has challenged and asks us to relinquish in favour of a theory of psychoids or a pseudo-metaphysical view of life.
The vitalistic position may be assailed from two points, the scientific and the philosophical.
In the first place the vitalist asserts that mechanism is inadequate to explain the phenomena of metabolism, of transmission of nervous stimuli, or of development. It is upon the last of these that Driesch lays special stress.
He has urged, as we have seen, that although a mechanical explanation might be given (such an explanation has indeed been put forward by himself) of the specific differentiation of the organism by supposing the first-formed elementary organs, developed out of the substances given in the initial structure of the germ, to act and react upon one another in accordance with a certain harmony, provided for by the same structure; yet a mechanism which can be subdivided ad libitum or almost ad libitum, and each part of which will still give rise to a complete organism, is not to be conceived. The answer to this objection has, however, been supplied by the experiments of Driesch himself and of many others. For though it is true that each of the first two, four, eight, or even in some cases each of the first sixteen cells into which the fertilized ovum becomes segmented, can, when separated from its fellows, give rise to a complete organism, yet in all cases there comes a time when the parts cease to be totipotent and produce not whole but partial structures.
This invariable restriction of potentialities, which occurs earlier in some cases than in others, and is not due to mere deficiency of substance, is not hard to account for.
Those substances on the presence of which in the ovum, as experiment has taught us, the formation of the elementary organs of the embryo or larva depends, are arranged in different cases in different ways: and they certainly may be, and very frequently are, so distributed that while each of the first four cells contains a like quantity of each of these specific substances, arranged in it exactly as they were in the whole ovum, the next division will sunder these materials in such a way that of the resulting eight blastomeres four will have more of one of the primary egg-substances, less of another; the amounts apportioned to the other four being in just the inverse ratio of this: and the result will be a difference in the fate of the cells when they are isolated from one another. In those of the one group the proportions of the organs developed out of these substances will not be the same as they are in the other. This is precisely the result which experiment has revealed; it is exactly this result which Driesch has ignored, or rather attempted to explain away.
It is evident, then, that to some extent the parts of this mechanism are interchangeable, that it can be subdivided, and that each part, brought now under new conditions, will still possess the potentialities of the whole, just as such a mechanism as a rocket, out of which, under the appropriate stimulus, a certain pattern of stars is developed, might be subdivided into two or more rockets of half size or less. There is, however, a limit to this interchangeability, while if the subdivision be carried beyond a certain point the totipotence of the parts is lost.
If the number of these organ-forming substances given in the germ were very large, as large, let us suppose, as the total number of separately inheritable characters, it might indeed be difficult to imagine a mechanism divisible into even two totipotent parts. But from the need for this assumption we are saved by the second part of Driesch’s own Analytische Theorie, which accounts for subsequent processes of differentiation by attributing the production of new parts to the mutual interactions of those that are the first to appear. For this also experimental evidence, though meagre, is not lacking, while a close parallel is found in the dependence of certain bodily functions upon substances—the hormones of Professor Starling—secreted by other organs.
In the second place the vitalist maintains that the processes of metabolism defy, nay more, always will defy, chemical and physical analysis. The first part of this statement may be a true description of the knowledge of to-day, but the existence in the living body of the same elements as are met with elsewhere, the synthesis of complex organic substances, the establishment of the equivalence of the energy which leaves the body as mechanical work or heat to that which enters it in chemical form in the food, should surely make us hesitate before abandoning all hope of attaining to a chemistry of life.
And thirdly, there are physiologists who believe that the complex phenomena presented to us in the activities of the nervous system are susceptible of a purely mechanical explanation.
‘A feature’, says Gotch, ‘which more particularly suggests spontaneous cellular activity is the well-known fact that centrifugal discharges may continue after the obvious centripetal ones have ceased. This is pre-eminently the case when the central mass is rendered extremely unstable by certain chemical compounds, such as strychnine, &c. There are, however, suggestive indications in connexion with such persistent discharges. The more completely all the centripetal paths are blocked by severance and other means, the less perceptible is such persistent discharge, and since nervous impulses are continually streaming into the central mass from all parts, even from those in apparent repose, it would seem that could we completely isolate nerve-cells, their discharge would probably altogether cease.’ Even in the hyper-excitable condition produced by strychnine the spinal motor nerve cells do not discharge centrifugal impulses when cut off from the centripetal connexions. The physiologist, therefore, has ‘definite grounds for believing that, as far as present knowledge goes, both the production and cessation of central nervous discharges are the expression of propagated changes and that these changes reveal themselves as physico-chemical alterations of an electrolytic character. The nervous process, which rightly seems to us so recondite, does not, in the light of this conception, owe its physiological mystery to a new form of energy, but to the circumstance that a mode of energy displayed in the non-living world occurs in colloidal electrolytic structures of great chemical complexity.’
To all these considerations we must add the fact that life did once originate upon this planet from matter which was not alive, and that even now some inorganic phenomena present at least remote analogies with certain vital processes. Such are the structure, the spontaneous division, and the regeneration of crystals.
We turn now to the philosophical objections that may be raised to vitalistic speculations; and here we must be careful to distinguish what we may term the psychological from the metaphysical form of the theory.
Driesch has maintained that the belief in a morphaesthetic psychoid finds support in the philosophies of Kant and Aristotle. Let us examine the merits of this claim.
Like the scientists of to-day, Kant, in his Critique of the Teleological Judgement, lays it down as a rule that the mechanical method, by which natural phenomena are brought under general laws of causation and so explained, should in all cases be pushed as far as it will go, for this is a principle of the determinant judgement. There are cases, however, in which this alone does not suffice. The possibility of the growth and nutrition, above all of the reproduction and regeneration of organisms, is only fully intelligible through another quite distinct kind of causality, their purposiveness. Organisms are not mere machines, for these have simply moving power. Organisms possess in themselves formative power of a self-propagating kind, which they communicate to their materials. They are, in fact, natural purposes, both cause and effect of themselves, in which the parts so combine that they are reciprocally both end and means, existing not only by means of one another but for the sake of one another and the whole. The whole is thus an end which determines the process, a final cause which brings together the required matter, modifies it, forms it, and puts it in its appropriate place. Such purposiveness is internal, for the organism is at once its own cause and an end to itself, not merely a means to other ends, like a machine whose purposiveness is relative and whose cause is external.
Such is the principle of the teleological judgement. It is a heuristic principle rightly brought to bear, at least problematically, upon the investigation of organic nature, by a distant analogy with our own causality according to purposes generally, and indispensable to us, as anatomists, as a guiding thread if we wish to learn how to cognize the constitution of organisms without aspiring to an investigation into their first origin.
Could our cognitive faculties rest content with this maxim of the reflective judgement it would be impossible for them to conceive of the production of these things in any other fashion than by attributing them to a cause working by design, to a Being which would be productive in a way analogous to the causality of intelligence. Natural science, however, needs not merely reflective but determinant principles which alone can inform us of the possibility of finding the ultimate explanation of the world of organisms in a causal combination for which an understanding is not explicitly assumed, since the principle of purposes does not make the mode of origination of organic beings any more comprehensible. And then, in a passage remarkable for its prophetic insight, Kant proceeds to show how this might be. This ‘analogy of forms’, he says, ‘which with all their difference seem to have been produced according to a common original type, strengthens our suspicion of an actual relationship between them in their production from a common parent, through the gradual approximation of one genus to another—from those in which the principle of purposes seems to be best authenticated, that is from man down to the polype, and again from this down to mosses and lichens, and finally to the lowest stage of nature noticeable by us, namely, crude matter’. And so the whole technic of nature, which is so incomprehensible to us in organized beings that we believe ourselves compelled to think a different principle for it, seems to be derived from matter and its powers according to mechanical laws like those by which it operates in the formation of crystals. A purposiveness must, however, be attributed even to the crude matter, otherwise it would not be possible to think the purposive form of animals and plants.
Although there are doubtless in the Critique many obscurities and inconsistencies, to which we cannot allude now, the general meaning of Kant’s reflections upon organisms is perfectly clear. He who would ‘complete the perfect round’ of his knowledge must think not only in beginnings but in ends. The end in the case of a living being is apparently plain—it is the maintenance and reproduction of its form; the end in the case of the cosmic process is to be sought in the ethical, or, in Kantian phraseology, the ‘practical’ concept of the freedom of the moral consciousness of man.
Such a position is quite intelligible, philosophically, but the testimony it brings to the theory of the psychoid is of very doubtful value, as Driesch is well aware. He complains indeed that Kant’s teleology is descriptive or ‘static’, rather than ‘dynamic’, as is perfectly true, except in the case of man, a point of which Driesch naturally makes the most. There are, no doubt, passages where Kant speaks of ‘a cause which brings together the required matter, modifies it, forms it and puts it in its appropriate place’; but against these must be set the explicit statement ‘that if the body has an alien principle (the soul) in communion with it, the body must either be the instrument of the soul—which does not make the soul a whit more comprehensible—or be made by the soul, in which case it would not be corporeal at all.’ Vitalism can glean small comfort from this. Let us turn, then, to the second authority.
As we have seen already, the souls or functions of nutrition and perception are, in the Aristotelian biology, ultimately to be expressed as alterations or movements of the particles of the body; mind alone is separable from body and eternal.
In the development of the individual organism the mind comes in from outside, but the two souls of lower order are present in the σπέρμα, or κύημα, as Aristotle calls it, which results from the commingling of the male and female elements, or, as we should say, the fertilized ovum. The material and efficient causes of development are not, however, both contributed by each of the parents.
The teaching of Aristotle is that the matter is provided by the female and the female alone. The egg (or catamenia in mammals) is described as being mere matter (ὕλη), body (σω̑μα), potentiality (δύναμις), passive (παθητικόν) and merely quantitative, although it is true that a sort of soul, the nutritive, is somewhat grudgingly conceded to it, since unfertilized eggs appear in some sense to be alive. The male element, on the other hand, provides the principle of motion (ἀρχὴ τη̑ς κινήσεως) and the form (εἰδος); it is qualitative, it is activity, it produces the perceptive soul, if it is not itself that soul, and it is responsible for the ‘correct proportionality’ (λόγος) of the organization. The male element contributes only motion, but no matter; it acts upon the female element as rennet acts when it coagulates milk, except that the analogy is incomplete, since the γονή brings about a qualitative and not merely a quantitative change in the material on which it operates. To this it imparts the same kind of motion which itself possesses, the motion which was present in the particles of the food in its final form from which it was itself derived. The communication of this motion is enough to set going the machinery (αὐτόματον); the rest then follows of itself in proper order.
Lastly, the sperm of the male acts like a cunning workman who makes a work of art, using heat and cold as the workman uses his tools: for this heat and this cold could never of themselves—by coagulations and condensations—produce the form of the body as the older naturalists had supposed, regarding only the efficient and ignoring the formal and the final cause: for the organic body is not what it is because it is produced in such and such a fashion, rather it is because it is to be such and such that it must be developed as it is.
And here lies the kernel of the whole matter. For while Aristotle has made it perfectly plain that, according to his idea, the soul, at least its nutritive and perceptive faculties, is to be regarded as a function of matter and that this function may be ultimately expressed in terms of movement, and further that development is a mechanism which is set going by the communication of motion proceeding from the ‘soul’ of the male element and derivable eventually from the motions into which the ‘functions’ or ‘soul’ of the parent can be resolved to the mere matter which the female provides, it is equally evident that he does not regard this mechanical explanation—in terms of material and efficient causes—as satisfactory or complete. But when we inquire why, he gives us no certain nor consistent answer. On the one hand, there are passages in which he tells us that there must be something which controls the material forces and imposes on them a limit and proportionality of growth; that the soul makes use of them as the artist makes use of his implements, and such passages are naturally interpreted by Driesch in the sense of a ‘dynamic’ teleology; it is the ψυχή which superintends and controls, and the ψυχή is ‘entelechy’.
Elsewhere, however, we are informed that even the proportionality of the developing parts is simply the outcome of the motion imparted by the male, which is actu what the female element only is potentia.
Moreover, it may be questioned whether Aristotle ever intended to imply more than an ‘analogy with the causality of purpose’ when he uses the figure of the workman and his implements to illustrate his meaning of the formal cause. The formal cause of a work of art is an intelligible vera causa; it is the idea in the mind of the artist antecedent to the execution of the work; but the formal or final cause of an organism, the end which it apparently strives to attain, can only be said by a metaphor to be prior in time to the existence of the organism itself. Prior in thought, however, it certainly is, for it is only the performance of its functions (ἐντελέχεια) by the organism complete in all its parts that makes the mere mechanism of development comprehensible to us; the process, therefore, exists for the sake of the end. Only as efficient cause is the soul prior in time; only so far as it is prior in thought can it be said to be a final cause.
Such a teleology is, it is obvious, indistinguishable in principle from the position in which Kant leaves us. It is the position adopted by Driesch himself in his earlier Analytische Theorie, but abandoned in the Vitalismus in favour of a theory of ‘psychoids’.
Now quite apart from the meaning which Aristotle may or may not have intended to convey, there are grave objections to this belief. This ‘psychoid’, to which the name ‘entelechy’ is surely misapplied, this rudimentary feeling and willing, which is aware of the form it desires to produce, must be psychically at least as complex as the phenomena it is designed to account for, and stands, therefore, as much in need of explanation as they; as Kant has observed, this will involve us at once in an infinite series of such entities. In fact it is only a photograph of the problem, and not a solution at all.
Again, when we ask what the modus operandi of this cause is, we get no reply either from Driesch or from any other neovitalist. The objection that the intervention of a psychical cause in a physical process is unintelligible, an objection which would probably appeal to many, may be waived, for in the last resort the connexion between any—even simple mechanical—causes and effects is equally hard to understand.
It may, however, be doubted whether these entities are not being multiplied beyond necessity, and whether the progress of science would not be better served by an adherence to a simpler philosophy. But even when it has discarded the psychoid we find vitalism still denying the possibility of mechanical explanation, still preaching the autonomy of the organism. The ‘dynamic’ teleology of Driesch has only disappeared to be replaced by the metaphysical doctrine of the final cause.
We may point out, perhaps, in passing, that the organism is by no means as autonomous as might be desired. The end towards which the creature strives, the maintenance and reproduction of its own specific form, is not a constant terminus ad quem, for species are as mortal as individuals: nor is it always achieved; the autonomy of a worm, which, bisected in a certain way, regenerates a tail instead of a head, or of a frog, which, after a particular injury, develops six legs instead of two, has surely renounced its rights. But, setting this aside, it must be seriously questioned whether any good purpose is served in biological discussion by decrying the value of mechanical conceptions or by confounding two distinct orders of thought. The questions are grave ones: for the issue at stake is no less than the existence of physiology as the science of the causes of living activities.
‘Recte ponitur’, said Francis Bacon, ‘vere scire esse per causas scire.’ The maxim of the great founder of modern inductive science has been the lode-star of biology in the past, and is still its watchword to-day. By exact observation and crucial experiment, utilizing every canon of induction, the activities of the living organism are to be brought under wide general laws of causation, which will be, in the first instance, physiological laws—of response to stimuli, of metabolism, and of growth: by means of these laws predictions can be made, and verified as often as we please. But no bar can legitimately be set to the scope of human inquiry; the thought process will not rest here, and ultimately it may be possible to state the widest generalizations of biology in chemical and physical, and these again in purely mechanical terms. The maintenance and evolution of form in the individual, as well as the larger evolution of form in the race, become but the final terms in a far vaster cosmic process, from ‘homogeneity to heterogeneity’.
The idea is, of course, perfectly familiar: it is the analysis of purely physical causes, carried to its extreme limit. Phenomena are thought out in terms not of origins merely, but of one origin, and that one origin is the only mystery that remains. This unification of the sciences has always been and must still remain the dream and the faith and the inspiration of the scientific man, and could such an edifice of the intellect ever be realized, the task of science would have been completed. Only when this purely deterministic method has been pushed as far as it will go does science leave off; only where science leaves off does philosophy begin.
There is an order of time, and there is an order of thought. Science works in the order of time, and necessarily so: for although science can never say what constitutes the invariable link between antecedent and consequent which it terms causal, yet it rightly speaks of the first as cause, determining the second as effect, since it is its function to predict from the past which is known to the future which is not.
But the outlook of philosophy is different. Dissatisfied with the endless regress of cause and effect, sceptical of first causes and original homogeneities, out of which by no conceivability could any heterogeneity have ever been developed, philosophy looks to the end.
The activities of living organisms at least appear to be directed to an end; they are apparently purposive, and it is this purposiveness which lends to biology, though built on the fundamental conceptions of chemistry and physics, peculiar features of its own, and is, of course, answerable for the teleological language which biologists so frequently employ. And by a knowledge of the end, the view of science, to which qua science it cannot too rigidly confine itself, will doubtless be supplemented and enlarged.
But, plain and definite though the end of an individual life may be, the end of the race—of the human or any other race—the end of the universe, are things only to be guessed at, and all we are left with is an indefinite series of evolving systems emerging out of an infinite past and fading into an infinite future.
In the final issue, indeed, the last effect is as delusive an ignis fatuus as the first cause. The philosophy which has rejected one must divest itself of the other, and seek its end, if anywhere, in the logical prius of the mind, which, though last in time, is yet first in thought, since through it alone can that ordered knowledge of nature which we call science be born and brought to perfection.
From the Italian translation of ‘KETHAM’, VENICE 1493
Plate XXVII. MUNDINUS(?) LECTURING ON ANATOMY
BIBLIOTHÈQUE NATIONALE MS. fr. 2030
Written in 1314
TO ILLUSTRATE THE ANATOMY OF
HENRI DE MONDEVILLE
BODLEIAN MS. ASHMOLE 399 fo. 34 r
Plate XXVIII. A DISSECTION SCENE
circa 1298