§ 1. The Inadequacy of a Mechanistic Description of Organisms Is a Negative Conclusion. § 2. The Problem: Vitalism or Mechanism, or Neither? § 3. Are Organisms Unique in Virtue of their Complexity? § 4. Have Organisms a Monopoly of Some Peculiar Energy or Energies? § 5. Is there a Non-perceptual Vital Agency resident in Organisms and Operative in distinctively Vital Activities? § 6. Descriptive or Methodological Vitalism: the Biological View. § 7. Speculative. § 8. Retrospect. § 9. Why Cannot the Controversy between Mechanistic and Vitalistic Theory be Ended?
§ 1. The Inadequacy of a Mechanistic Description of Organisms Is a Negative Conclusion.
WE have considered the chief characteristics of living creaturessuch as persistence in spite of change, cyclical development, and effective agency. We considered the organism under the category of a material systemto see how that fitted, and we reached the conclusion that, while this is a legitimate and useful way of looking at a living creature, the formulæ of physics and chemistry are inadequate for the re-description of the everyday bodily functions, or of behaviour, or of development, or of evolution. We did not reach any conclusion as to the depth of difference between organisms and not-living things; our result was a negative one, that the chemico-physical formulæ do not suffice for answering the distinctively biological questions.
It is an unfortunate tendency of the human mind to regard evidence against one theory as evidence in favour of another. This holds only when we are dealing with two logical opposites, one of which must be true. Many times over in the history of thought there has been a rebound from mechanistic interpretation discovered to be inadequate, and the rebound has almost always landed the inquirer in a doctrine of positive vitalism, in the assumption that there is some non-perceptual agency at work in a living body which is not present in the inorganic domain, and without which the results would be otherwise. We shall not jump to this conclusion, but we must consider it carefully. In its clearest form it asserts the actuality of a vital principle, or vital impulse, or entelechy, of a non-perceptual character, occasionally operating in living creatures and operating directively. Is this a tenable theory?
§ 2. The Problem: Vitalism or Mechanism, or Neither?
Before we discuss the theories of vitalism, it may be useful to refer to three preliminary considerations.
(a) It is maintained by some that mechanistic formulation (i.e., description in terms of matter and motion) is not exhaustive even within the domain of the not-living. It seems to be adequate for certain purposes, e.g., when the navigator deals with the tides, but is it certain that it is an ideal formulation for things in general? Does it take account of everything, e.g., of the probability that the living evolved from the not-living? But the adequacy of mechanical categories in the domain of the inorganic is a question for expert physicists; it is not the biologist's business. Our question is whether the formulæ which work adequately, if not exhaustively, in describing the not-living world, are beginning to answer the distinctively biological problems. If not, what alternatives are there?
(b) Secondly, there is a sense in which all biologists may be called vitalista, inasmuch as no one can pretend that the mechanical re-description of vital phenomena has as yet gone very far. Professor Bateson writes: If those who proclaim a vitalistic faith intend thereby to affirm that in the processes by which growth and division are effected in the body, a part is played by an orderly force which we cannot now translate into terms of any known, mechanics, what observant man is not a vitalist? (1913, p. 80).
We must distinguish between a negative and a positive vitalism. When we assert that no vital activity in its observed totality has ever been completely described in mechanical terms, as one might describe the movement of a glacier or the spread of a conflagration, we are making a scientific statement which we believe to be accurate at the present time (1919). That it will hold true a hundred or a thousand years hence does not follow from the evidence submitted, for we do not know what changes are still to be made in the concepts of chemistry and physics, or what discoveries will reward inquiry into, for instance, the physiology of correlation. It may be that a mechanistic formulation of the essential activities of organisms is quite impossible, but that could not be legitimately inferred from the arguments we used. These went to show that the description of vital occurrences in terms of present-day chemistry and physics does not adequately express the connection of the sequences, still less their correlation. We can speak only about the chemistry and physics that we know. Sufficient unto the day is the mechanism thereof. The formulæ of chemistry and physics prove inadequate, and in part irrelevant. If we go on to say that they are inadequate because the organism has a monopoly of a peculiar kind of energy, or because it has an entelechy, we are embarking on a new adventurethat of a positive vitalistic theory.
(c) It is held by some that it is the presence of consciousness or some expression of mentality, that makes all the difference, and here again there is probably a great truthto which we point in using the terra Animate Nature. But the suggestion as it stands cannot be pressed in the meantime, for the obvious reason that there are many living creatures about whose mind or consciousness we cannot make any secure statement, where even the argument from analogy fails us. So it must be clearly understood that the problem of vitalism is different from that of animism. The problem of vitalism would remain even if the world held only plants and no animals besides ourselvesJack and his beanstalk, in fact. Now whatever we may believe, we do not know anything about the mind of the beanstalk. Yet we may, and do maintain that mechanistic formulæ do not suffice to answer our biological questions concerning the beanstalk.
Among those who hold that plants and animals stand apart from things in general, we may distinguish three grades. (I) The first view is that the configurations that occur in organisms are so different from those in the inorganic domain that the activities of organisms cannot be predicted from any formulation of what occurs in inorganic systems. This is the very thin edge of vitalism. (II) The second view is that there operates in living creatures a new kind of physical energy which does not operate elsewhere. This is a lineal descendant of the mediæval form of vitalismthe doctrine of a vital force. (III) There is the theory of a non-perceptual vital agency or entelechy which operates directively in organisms. This is the clearest and the most thoroughgoing form of vitalism.
If the term vitalism be restricted to (III), as many would restrict it, and if a mechanistic theory mean that the categories of physics and chemistry suffice for the adequate description of the life of organisms (leaving mental processes out of account), then we suggest that the proper answer to the question Mechanism or Vitalism? is Neither. We regard the question as one of the many false dichotomies with which Man in his search after clearness has been led astray. The biologist is not bound to accept either a Vital Force Theory, or a Machine Theory; he may demand a biological theory in terms of concepts neither transcendental nor mechanical.
§ 3. Are Organisms Unique in Virtue of their Complexity?
The first position, recognising, as every one must, a notable difference between an organism and a not-living thing, finds the difference in the much greater material complexity. The configurations of elementary particles are so much more intricate in organisms that the activities of organisms cannot be predicted from our formulation of what occurs in inorganic systems. This idea applies in other fields: If we have never seen more than two or three people together, we are not likely to be able to predict how a great crowd will behave. The mechanist passing to the study of living creatures is like the student of inorganic chemistry who is suddenly confronted by the carbon compounds; he is assured that he is still at the same science, but be finds this difficult to believe, the data are so different. This is a vitalistic view in so far as it recognises the apartness of living creatures from things in general, but it does not admit that the problem of the Amba on the hunt is more than a very difficult problem in dynamics. It does not admit that new concepts are required for the description of the activities of living creatures. The biologist may be allowed a laboratory to himself as a matter of convenience and courtesy, just as there is a laboratory for Electrodynamics quite apart from another for Hydrodynamics. But the idea of biology being an autonomous science must be nipped in the bud.
It is interesting to notice that many physicists, who are familiar with the capabilities of mechanical formulation, have been very cautious in their statements regarding the extension of this to vital phenomena. Gauss, Cauchy, and Kelvin may be mentioned as investigators of the first rank in mathematics and physics who regarded life as belonging to an entirely different field. Hertz again was very careful: We can neither maintain that the internal phenomena of animated beings obey the same laws (as in inanimate nature) nor that they follow other laws. Our principle, sufficient perhaps to describe the motion of lifeless matter, appears at least prima facie to be too simple and limited to describe the manifoldness of even the lowest vital phenomena.
Lord Kelvin's view was more dogmatic, and assertive rather than reasoned. Yet it is important, for surely he, of all men, must have known how far his physics would carry him. The only contribution of dynamics to theoretical biology is absolute negation of automatic commencement or automatic maintenance of life. The opening of a bud, the growth of a leaf, the astonishing development of beauty in a flower, involve physical operations which completed chemical science would leave as far beyond our comprehension as the differences between lead and iron, between water and carbonic acid, between gravitation and magnetism, are at present. A tree contains more mystery of creative power than the sun, from which all its mechanical energy is borrowed. An earth without life, a sun, and countless stars contain less wonder than that grain of mignonette.
With the first grade of vitalismthat the problem of the homing of the bird is only a very complicated form of the problem of the return of the boomerangwe cannot be satisfied. And a sufficient reason for dissatisfactionthough not the only oneis to be found in the fact that it has not yet been found possible to give a mechanistic answer to any biological question. We know a great deal about the structure of muscle, the chemical, thermal, and electrical changes that go on in muscle, but we cannot give a chemico-physical account of the contraction of a muscle. If explanation by analysis had begun to be successful, we might hesitate before resorting to explanation by synthesis, as we do, for instance, when we say that the bird comes home because it is a creature in whose present the enregistered past counts.
§ 4. Have Organisms a Monopoly of Some Peculiar Energy or Energies?
According to the second grade of vitalism, there is a peculiar kind of energy operative in living creatures and nowhere else. Organisms have a monopoly of some power in the same (perceptual) series, as, say, electricity. This is a continuation of one form of the old hypothesis of Vital Force, and it has not found many supporters in recent years. But it is an honest theory, and may be illustrated by a reference to the work of a thoughtful biologist, Prof. M. Hartog of Cork. Every one admits that one of the commonest phenomena of life is also one of the most staggering, namely, cell-division. After extraordinarily intricate and uniform internal movements of particles a cell divides with meticulous accuracy into two precisely similar halves, sometimes, strange to say, into two quite dissimilar halves. As we have already remarked, it is one of the wonders of the world. Like not a few others, Professor Hartog has been studying the dividing cell for many years, and he believes that he has discovered a new force operative in the process. He is quite clear that well-known physical forces are at play in the dividing cell, such as mechanical tensions, surface tensions, and osmotic actions; he is also clear that agencies are at work which occur elsewhere in living organisms, but whose physical interpretation is uncertain, such as protoplasmic streaming; yet when he has made allowance for all these he finds evidence of the working of a new force which he calls mitokinetism. He does not know the proximate cause of this force or its relation to other forces, he knows it by its works, and he cannot identify it with any other force, electrostatic for instance. Nor does he base his own vitalistic belief on his mitokinetism. We have here the basis of a theory that organisms have a monopoly of some peculiar energy or energies, and are therefore apart both from machines and from not-living things in general.
A clear statement of this position was given by the late Prof. Richard Assheton, who suggested that instead of being satisfied with the more or less mystical Entelechy we should look out for some form of energy peculiar to living matter. In 1894, Roux observed that if the cleavage-cells of the ovum of the frog (Rana fusca) towards the end of segmentation be isolated and floated in a suitable medium, they show mutual attraction. The sides of one cell become drawn out towards a neighbouring cell; the cells move towards one another and touch; they actually become pressed and flattened up against one another. This interesting attraction was called by Roux cytotropism or cytotaxis, and it has been observed in other cases. Assheton was particularly concerned with the development of the lancelet or Amphioxus, where the ovum divides into a hollow hall of cells, which again is indimpled or invaginated to form, a two-layered sac of cells, the gastrula. Assheton sought to show that, if there were an attractive force between cell and cell, acting from centres represented by the nuclei of the cells, the hollow ball of cells would at a certain stage become invaginated. The explanation of how gastrulation might come about was put forward as indirect evidence in favour of the existence of some force acting from a centre like gravitation or magnetism or statical electricity, but probably of a different nature and with different laws, and an attribute of living matter alone. Assheton meant definitely a kind of physical energy which could be investigated by the ordinary methods of mensuration and computation available to the mathematician.
Herbst made the remarkable observation that if the ova of the sea-urchin be allowed to develop in sea water deprived of its calcium salts, the blastomeres separate from one another, instead of adhering. What looks like repulsion between two centres is seen in the normal process of cell-division, where the incipient daughter-nuclei, while still parts of the parent cell, seem to repel one another, and yet immediately after separation appear to attract one another strongly. Assheton suggested that the hypothetical form of energy exhibits an unceasing recurrence of a bipolar state out of a unipolar state. The attraction and repulsion observed between cell and cell are certain of the manifestations of this supposed form of energybut probably not by any means all; just as attraction and repulsion are manifestations of electrical energy under certain conditions, but are not by any means the only manifestations. Dr. Assheton went on to suggest that in nerve impulses we may experience manifestations in another way of the same form of energy which under other conditions produces the attractions and repulsions and the figures of strain in the dividing cells, and the actual cell division. Driesch's Entelechy, he concludes, although not supplying the essential qualities of a driving force, may perhaps be a complex system of a simpler vitalistic force with other forces which has within certain limits a balancing or compensatory influence upon the course of development like that which a gyroscope has in compensating (within certain limits) for disturbances to the course of a monorail vehicle (p. 76).
The disadvantages of this position are the following: first, it is difficult to prove the independence of the alleged new force or energy; second, to attach much theoretical importance to it reminds us warningly of the old mistake of making much of organic compounds, which it was alleged, could not be formed without the aid of the vital force resident in organism; third, the inadequacy of the physico-chemical formulæ to describe animal behaviour or the like, does not appear to be of a kind which would be affected by the discovery of a new form of physical energy either within or without the organism. Yet the theory that there may be a special kind of power or energy operative in living creatures is on the lines of sound science, and must be impartially tested by biologists. There seems nothing very unlikely in the idea that living matter may be able to effect an organisation of movement in some way which we do not understand. The theory has nothing to do with Ostwald's suggestion that the chemical energy of protoplasm may be transformed into the mental energy of thinking, which seems to us a contradiction in terms.
It is stated that the movements of molecules in the domain of the inorganic obey the law of probability; it is interesting to ask whether that is true of the molecules within organisms (see Soddy, Matter and Energy, p. 101). But we cannot suggest a test case! Is it conceivable that, just as lowering the temperature of a gas makes it into a liquid whose molecules below the surface have movements quite different from what they had in the gas state, so complicated molecules in a colloid state have movements which obey some other law than that of probability, and is it conceivable that the reality of which the molecular movements are one expression then begins to show another aspect, perhaps, as some would say, a metakinetic aspect?
§ 5. Is there a Non-perceptual Vital Agency resident in Organisms and operative in Distinctively Vital Activities?
The third view is thoroughgoing vitalism, best represented by Driesch, whose ingenuity and consistency command our admiration. Its postulate is a non-perceptual vital agency, which does not occur in not-living things but is confined to organisms, where it operates in certain cases, directing the chemico-physical processes so that their results are different from what they would have been apart from its intervention. Three points should be carefully noted:(1) that the postulated vital agency or entelechy is not the outcome of more complex physical conditions, not a new elemental consequence of some constellation; (2) that it only intervenes at certain steps, introducing an occasional indeterminism; and (3) that it is supposed to be a genuine agent, counting for something, at work as Driesch says. On this view, obviously, there is a deep-lying distinction between the flight of a bird and the movement of a comet, and Biology is by hypothesis autonomous. A general statement of this third position, apart from Driesch's particular formulation, has been given by Ritter (1911, p. 437). After stating that materialism is the belief that all vital phenomena can be completely explained in terms of the material elements that go to make up the organism, he defines vitalism as the belief that organic phenomena cannot be fully explained by referring them to the material elements of which organisms are composed, but that something not really belonging to the natural order, either explicit or implicit, is present in living things. The essence of the conception, whatever be its variety or form of statement, is that something absolutely new and novel came into the world when living beings came and that this came as a special force, or principle, or factoranything you have in mind to call it, so long as it is not material. A further essential to the conception is that this new thing is elemental, protean, once-for-all. It is not exactly the life itself of the organism. It is rather the informing, underpinning, ultimate motor, of life.
The general nature of the argument that Driesch uses to support his conception of Entelechy may be briefly indicated. He takes in particular the facts of morphogenesisthe development of the embryo or the regeneration of a lost part. If what takes place is determined solely by physical factors there must be something in the nature of a very complex machine in the egg or at the cut end of the hydroid branch from which a new polyp grows. He allows the imagination to erect this machine with all conceivable intricacy and device, and then proceeds remorselessly to bring forward fact after fact which contradicts the possibility of such, a machine accounting for the result observed. Thus by an argument by exclusion he seeks to prove that the development must be determined by a non-spatial, non-perceptual agent or Entelechy.
(a) One of the objections to thoroughgoing vitalism is that it implies a definite breach in the fundamental law of the conservation of energy. If a non-perceptual agency occasionally directs the chemico-physical operations of the body, there must be some exertion of power which does not figure in the chemical and physical accounts. The calorimeter experiments seem to show that for a man in a closed system the expenditure is equal to the income over a term of days. There is no gap for the intervention of a physical agency; no, not for a moment. This is a serious objection, yet apt to pierce the hand of those who rely on it. For it is a rash procedure to use a physical generalisation as a dogma in the realm of organisms. It is begging the question. Boyle's Law did duty for a couple of centuries before physicists discovered that it is accurate only between certain limits. The Law of Gravitation does not hold below certain sizes and distances. Perhaps the Law of the Conservation of Energy does not quite hold for living creatures. The calorimeter experiments are not so absolutely exact that it can be asserted that the balance at the end of the day is precisely what it should have been if the organism were a mechanism and nothing more, and that therefore an Entelechy does not exist. One remembers that a very minute expenditure of energy may effect a great deal, just as cutting a tape or pressing a button launches a vessel. Driesch's Entelechy is supposed to act by inhibiting for a time the transformation of one kind of energy into another.
In a case of this sort it is the opinion of expert physicists that is most valued, and in discussing the analogous case of the operation of our will, the late Prof. J. H. Poynting, an authority of eminence, suggested that a merely deflecting force does no work though it changes configuration. The will may introduce a constraint which guides molecules to glide past one another instead of clashinga slight change of spin which may be compensated for by a slight opposite spin put on the rest of the body. The will may act as a guiding power changing the direction of the atoms and molecules in the brain, and we can imagine such a guiding power without having to modify our ideas of the constancy of matter or the constancy of motion or even the constancy of energy (Poynting, 1903, p. 745).
(b) A recurrent argument in Driesch's exposition of his doctrine of vitalism is that no machine-like agency can possibly account for the facts of development, inheritance, and behaviour. A machine is defined as a given specific combination of specific chemical and physical agents, and Driesch seeks to reduce to absurdity the theory that any machine could do what is required. His argument is very convincing, but of course we can argue only about machines that we know, and imaginative combinations or improvements of these, so it seems open to the critic to reply that no one knows all possible machines, and to urge that proving the untenability of a machine-theory does not prove the necessity of postulating an Entelechy.
Concerning the ingenious machinesalmost super-machinesinvented by man, it may not be needless to remind ourselves that their introduction into the argument is apt to be fallacious. For they, like the wonderful achievements of the synthetic chemists, are the fruits of intelligence, not fair samples of the inorganic world. An ingenious machine, like a type-writing or a calculating machine, is an elaborated tool, an extended hand, and has inside of it, so to speak, a human thought. It is because of these qualities that it is a little like an organism. Practically, however, most of those who have an intimate acquaintance with living creatures will agree with Driesch in the negative part of his position that their behaviour is not very like the working of machines. For certain purposes it is not amiss to think of the organism as an engine, but it is a self-stoking, self-repairing, self-preservative, self-adjusting, self-increasing, self-reproducing engine!
(c) Dr. J. S. Haldane states another objection. In order to guide effectually the excessively complex physical and chemical phenomena occurring in living material, and at many different parts of a complex organism, the vital principle would apparently require to possess a superhuman knowledge of these processes. Yet the vital principle is assumed to act unconsciously. The very nature of the vitalistic assumption is thus totally unintelligible. Because we do not understand vital phenomena in terms of mechanism, we postulate an Entelechy, only to discover that we have no idea how the Entelechy can know what to do. We believe that a dog's appreciation of the meaning of certain circumstances is real and an effective factor in its ensuing behaviour, and there are various ways of thinking of the dog's intelligent behaviour so that it does not appear magical or miraculous, but we find it difficult to think of the Entelechy's appreciation of an intricate chemical situation within the body. Even if we suppose a hierarchy of psychoids with division of labour, acting like the various men about a railway station, some of whom put people into the proper trains, while others put them into the proper compartments, others shut the doors and give the signals, and others work the points, the correlation of the whole by the chief Entelechy is just the problem we started with.
To many it appears that to assume the existence of an Entelechy does not help in the least. It seems to be merely a way of collecting all the difficulties together and giving the bundle a name. Professor Jennings asks persistently how the Entelechy gets its power of co-ordinating and harmonising. To accept the Entelechy unanalysed and unexplained is merely to give up the problem as insoluble. And if we try to work out a comparative development of Entelechies,then surely we are merely transferring our problem from the complex that we actually find in time and space to a sort of manufactured copy of this problem, presenting the same difficulties, with the additional one that it is impalpable and cannot be directly dealt with at all. The Entelechy simply adds to our difficulties.
We confess to some sympathy with those who ask why there should be all this straining and striving to remove organisms from the domain which includes the stars and precious stones, Northern Lights and dew-drops. For the world that we parcel out is probably one after all, and in any case there is no stigma in being mechanical. With this sympathy we would quote from a colleague:I am neither afraid nor ashamed to uphold (to the great length that I have gone) a mechanical theory of the organism and its activities, or rather of its reactions with the outer world. I do not admit that in doing so we degrade our conceptions, or belittle our notions, of the organism. The mechanical concept is no base one at all. The earth itself and the sea, the earth with her slowly changing face, and the sea multi-tudinous with all its tides and currents and great and little waves, constitute a mechanism; the heavens themselves, the sun and moon and all the little stars, are a glorious mechanism. The whole material aspect of the universe is a mechanism; we know not how it has its being, but we know that it lives and moves obedient to everlasting laws; and the same Benedicite Dominum is addressed to the Showers and Dew and to the Winds of God as to all that move in the waters and all that move in the air, and to all the Beasts and Cattle, and unto the Children of Men (D'Arcy Thompson, Life and Finite Individuality, p. 52).
This is admirably said, yet we do not think that the category of mechanism exhausts the reality of the earth and the heavens, still less that of the flower in the crannied wall. It is mainly a matter of method: Are mechanical categories sufficient in biology or must we have biological categories as well? For practical purposes, moreover, the theory of organism transcending mechanism is to be recommended. It has pragmatic sanction.
§ 6. Descriptive or Methodological Vitalism: the Biological View.
Looking backwards, we cannot accept the view that the study of animal behaviour is just the study of very intricate and at present insoluble problems in chemistry and physics; we cannot accept the view that organisms exhibit a new kind of physical energy or several of them; and we cannot accept the thoroughgoing vitalistic theory of an Entelechy. What, then, is our position?
We wish primarily and scientifically to stand for what may be called descriptive or methodological vitalism. Unable to attain any discernment of the essence of the difference between organisms and things in general, we hold to what we believe to be a fact, that mechanical formulæ do not begin to answer the distinctively biological questions. We do not doubt the value of bio-chemistry and bio-physics, but when these are added up the summation is not biology. We need new conceptssuch as that of the organism as a historic being which has traded with time, and has enregistered within itself past experiences and experiments, and which has ever its conative bow bent towards the future. We need these new concepts because there are new facts to describe, which we cannot analyse away into so-called simpler processes. In the present state of knowledge we cannot tell in what the newness essentially consists. This appears to us to be a quite legitimate stopping-place, without going on (except speculatively) to any positive vitalistic theory which must be, from the nature of the case, metaphysical.
The best statement that we know of methodological vitalism is that given by Mr. E. S. Russell, and we take one of his illustrationsthe migration of the European eel to its spawning ground in the deep, warm, and salt waters on the verge of the abyssal Atlantic. Chemical and physical methods can tell us muchhow the eel gets energy for its long journey, and a score of other things; they might conceivably give us an account of every transformation of energy within the eel from the time it left the pond to the time of its death in the dark abysses, but they do not illumine the biological fact of the eel's migration. As Mr. Russell says, The migration is, so to speak, a fact of a higher order than any physical or chemical fact, although it is made up of an indefinitely large number of physical and chemical facts. To explain the fact one must accept it as a whole, not seek to conquer by dividing it, for if one analyses it into its components one inevitably misses the bond of union. The explanation of a biological fact cannot be obtained by decomposing it, any more than the properties of a chemical compound can be deduced from the properties of its constituent elements. A biological fact is something more than a mere arbitrary assemblage of component physical and chemical facts, and the component facts may be explained without touching at all the problem of their composition. In the case of the eel it is possible to decompose the act of migration into a large number of acts of a different order, into the chemical reactions occurring in muscular movement, in nervous conduction, in the stimulation of peripheral sense organs, but by doing so one cannot but lose sight of the interconnection of these single acts, the interconnection which really binds together all these acts into the single act of migration. To decompose the act of migration into an infinity of physico-chemical processes is to take an infinity of little partial views of the act, but what one needs for an explanation of the fact is a comprehensive view which will unite all the relevant features of it into one picture. To the chemist confronted with the problem there is no fact of migration at all, there is only an intricate enravelment of chemical reactions; to the biologist the fact of migration to a particular region for a particular purpose is cardinal, and the chemical processes involved in the action are negligible.
But, it may be said, if the mechanistic description leaves the eel's migration obscure, does any other description fare better? The answer is that we must look at the migration in the light of what we know of organisms in general. It is certain, for instance, that what a living creature does is in part determined by the pastits own experience and the history of its race. In the organism, as Bergson says, the past is prolonged into the present. Living things therefore require an historical explanation. Non-living things, on the contrary, have no history in the biological sense of the word, and no inorganic thing carries its past about with it (Russell, 1911, p. 338). We have to pass, therefore, to a new level of explanation, and whenever we mention that the eel is one of a deep-sea race which has adventurously taken to colonising the fresh watersjust as the salmon is one of a fresh-water race which has taken to exploiting the resources of the sea,and notice further that many animals return to their birth-place to breed, and that some go back to their birth-place to die, a biological light begins to be shed on the eel's strange story. And we have but begun. Of course if the objector is prepared to maintain that the enregistering of experience by organisms is nothing more than a special case of the peculiar way in which colloids are influenced by their history, we can only say that this theory must get more facts to back it before we can take it very seriously.
No one wishes to slacken investigation into the physiology of migrationa most fascinating and suggestive inquiry. It is known that when eels become mature there is an alteration in the metabolism, and that the altered metabolism affects the carbon dioxide content of the blood, that this increases irritability, and that this increases range and vigour of movements, and, moreover, that changes in the metabolism of the animal affect its reactions to chemicals in the water, to gravity, and to currents. Much knowledge of this kind is accumulating, but it seems to many that it does not grip the problem unless it be taken along with the concept of the organismal enregistration of past experiences, individual and racial. We must bear in mind that organismal reactions are often very precisethe North Sea will not suit the eel, it must move on; that they are often extraordinarily insistent, as we may infer from Maitland's experiments on Smolts which were always jumping out of the pond at the time when they should naturally have been leaving fresh water; that the internal adjustments are so delicate that they begin to operate long before the situation is at all critical; and that, after all, what we see is an active searching out of regions or conditions of optimum stimulation.
§ 7. Speculative.
Such, then, is the position which may be called descriptive or methodological vitalism. If we are pressed to go beyond Science in the endeavour to form some connected reconstruction, we should say that those constellations of matter and energy which we call organisms afford opportunity for the expression of aspects of reality which are undetectable in the inorganic doman. Matter and energy are scientific concepts defined for the description of the so-called physical universe; they are defined by certain methodsthe intellectual instruments of physics and chemistry; they are admittedly reached by processes of abstraction. In dealing with the outer world apart from life, these formulæ work well, but we find no warrant for asserting that they exhaust the reality of Nature. They correspond to reality, for we risk our lives on this correspondence, but it does not follow that they are exhaustive. Reality is richer than they. For just as a physician may on occasions treat his patient successfully without recognising him as a rational being at all, yet will on other occasions fail grievously through not doing so, so it is possible that an aspect of reality which may be safely neglected, being latent or hidden, in one constellation of matter and energy, may be patent and dominant in another. Instead of supposing the intervention of vital impetus or Entelechies as bolts from the blue which enter organisms, may we not conclude that the qualities which render the postulation of vital impetus and Entelechy necessary to some minds have been in kind present throughout. We say in kind, since most naturalists agree in believing that we share in a movement which is not the unwinding of something originally given, but an evolution in which time counts.
Our argument for the autonomy of biology may be expressed in general form by saying that it recognises the correlation rather than the unity of the science of Nature. We find it technically stated by Prof. Arthur O. Lovejoy:Scientific unification takes place in so far as diverse classes of phenomena come to be recognised as deducible from a single, relatively simple generalisation concerning the correlation of certain variablesprovided that in each particular case the actual natures or values of the variables be known. And unification fails of attainment in so far as two or more kinds of phenomena appear (in the light of existing knowledge) as undeducible from any single, already verified law, even were the actual values of the variables referred to by any such law precisely ascertained for the phenomena in question. When two or more comparatively specific laws are, in the latter sense, incapable of being deduced from any common, more general, lawin other words, are not thus far unifiedwe may speak of the laws as being discontinuous with one another (1912, p. 17). He goes on to say that while discontinuity emerges if the behaviour of an animal is shown to be not deducible from the laws of thermodynamics, though in conformity with them, a greater discontinuity will appear if it should be shown that in some cases (distinctively vital processes) the motion of particles in an organism, say an Amba, neither follows from nor conforms to the motion of particles in an inorganic system, such as, let us say, a whirlpool.
It may be justly said that if Biology requires categories of its own, it should be able to give some indication of what they are. They may not be clear as yet, the science is so young, but they should be emerging. And surely some of them are beginning to be discerned. First, there is the fact of organic retention, the capacity of enregistering experience, garnering the past, capitalising gains. We see this in the results of training and habituation, in the establishment of organic rhythms or periodicities, in the organisation of steps which have proved adaptive, in the organic inertia which the hereditary relation reveals. Second, there is the self-maintaining, self-preserving, and purposiveness of the organism. Life has been defined as effective response, but it is more; it is effective prospectively as well as immediately, it is effective not only in external action, but in self-preservation. We see in the developing organism a remarkable conativeness, especially when what is artificially disarranged is put to rights again. We see in the simplest behaviour, where the meaning of things counts, an element of pre-awareness that is essentially teleological. Third, there is the fact of variability, the capacity and habit of giving origin to the new.
§ 8. Retrospect.
How does the biological position differ from the theories already illustrated? The first theory was that the activity of living creatures stands apart from that of not-living things only in being very much more complex. The biologicalview recognises that many describable chemical and physical processes occur in the living body; and admits that many more such processesand much more complicated oneswill be eventually sifted out,but insists that even if the ledger of all the chemical and physical transactions were complete, it would not furnish an account of the creature's life from day to day, nor of its behaviour, nor of its individual development, nor of its racial evolution; and why not? Because the concepts of chemistry and physics fail to grip. This is what one of the acutest and best-informed of modern methodologists, Professor Enriques, means by saying: The mechanical hypothesis does not appear to be incompatible with the phenomena of life, but it is unimportant for the study of these phenomena (1914, p. 385). And again he speaks of the irrelevancy of the mechanical explanation in biology (1914, p. 384). And why do the chemico-physical formulæ fail to grip the essential features of the activity we call living? Not because the processes involved are too difficult or too complexbut because they demand a different order of scientific explanation.
The second theory was that living creatures have exclusive possession of a peculiar form of energy in a line with the other forms of energy, like heat and electricity, and not in any way mystical, but amenable to experimental and mathematical treatment. The biological position differs from this in refraining (in the meantime) from any hypothesis as to the nature of the difference between stone and tree, between boomerang and homing bird, in being content with holding to the fact that new aspects of reality have somehow risen to the surface and demand other than mechanical formulation. Learning, choosing, struggling, and the like appear to transcend mechanism.
The third theory asserts that something not really belonging to the natural order, something not material, is present in living creatures, informing them, underpinning them, inspiring them. The biological view differs from this in keeping to the idea of continuity, in supposing that aspects of reality which in azoic days were only implicit became explicit in the first living creatures, and have become more and more patent as evolution has gone on.
We are here in the difficult position of agreeing on the one hand with the positive vitalists in their emphasis on the uniqueness of organisms as compared with not-living things, and yet of disagreeing with them (or many of them) in their emphasis on discontinuity. It is plain from our argument that our understanding of the facts of the case leads us to a high appreciation of the apartness of organisms and to a conviction that living transcends all mechanical description, but we are not compelled by this to a rejection of the central idea of Evolution, which is continuity.
To ignore distinctions yields false simplicity; to exaggerate them yields false complexity. There is very little individuality in the inorganic domain, but it must be remembered that gold and iron, phosphorus and sulphur, oxygen and nitrogen remain quite distinct things with properties and ways of their own, specific like organisms, each something of a law unto itself. There are, indeed, logical relationships between the elements as members of a system, and the radio-active elements are known to be transmuting themselves, but these facts also bear out our point that there is more analogy between the inorganic and the organic than at first appears. And just as the breeder and cultivator help to make new animals and plants, so the synthetic chemist makes camphor and sugar, rubber and alizarin, and the physicist as engineer makes the cleverest machines which borrow some of his own individuality. The breeder works mainly by analysis, the chemist by synthesis, but both are creative. We agree with those thinkers, like Lloyd Morgan, who have tried to link on the synthetic tendency which they detect in the formation of crystals and the building up of carbon compounds to the synthetic tendency which they see in organic development. Lloyd Morgan refers to the teaching of Nernst that, while a large number of physical properties are clearly additive, there are other properties which are non-additive, and should be called constitutive. The kind of influence of the atom in a compound is primarily dependent upon the mode of its union, that is, upon the constitution and configuration of the compound (Nernst, Theoretical Chemistry. Translated by Lehfeldt. Quoted in The New Realism, New York, 1912, p. 238).
Instead, then, of seeking to interpolate a new agencynon-material and not perceptualwe express the fact that living is not explicable in terms of matter and motion by saying that all organismsknown to our senses as collocations of protoplasmreveal new aspects of reality, transcending mechanical formulation. That these new aspects of reality are analogous to those which are exhibited by the higher organismsnamely, intelligence and personalitymay by and by appear, for our central idea is that the organism is a psycho-physical individuality. That they probably have their infra-conscious and implicit analogues in the domain of the inorganic is our metaphysical hypothesis, which is but little different from the Aristotelian dictum that there is nothing in the end which was not also in kind in the beginning;but little different from the doctrine that in the beginning was Mind.
§ 9. Why Cannot the Controversy between Mechanistic and Vitalistic Theory be Ended?
The persistence of the controversy between mechanism and vitalism has often been the subject of remark. Aristotle was a vitalist and his biology was in conscious opposition to the dogmatic mechanism of the school of Democritus. Yet we are facing the same antithesis to-day. Whence this terrible longevity?
Part of the answer is probably to be found in the intrinsic difficulty of the problem of vital activity, which seems to be midway between mechanical uniformity and our own conscious purposing. The secret of life is baffling, receding as we approach. Perhaps when it seems almost within the physiologist's reach, it is farthest away. Perhaps, as Bergson says, our intelligence is not suited for this quest, and we get nearest life in sympathy.
But apart from the unanswered question: What is the essential difference between the Amba and the crystal, between the bird and the boomerang, is there not something strange in the historical oscillations of opinion between mechanistic and vitalistic interpretation of the living organism? Now it is a machine and again it is a spirit, now an automaton and again a free agent, now an engine and again an entelechy. Why does the pendulum of reflection swing so? It is partly because new knowledge always rewards the prosecution of chemico-physical analysis, and the investigators, flushed with success, insist on premature generalisation. It is partly because vitalism is apt to become vague and mystical, provoking a positivist recoil which is, within its limits, quite wholesome.
According to Prof. W. E. Ritter, vitalism is the lineal descendant of early animism, sharing with it the assumption of non-material, essentially extra-corporeal forces or principles to explain observed phenomena. Similarly, materialism is the lineal descendant of early magic, sharing with it the assumption of crediting observed bodies with qualities which are not verifiable. Both attempt to explain everything in terms of something else, and this in essence amounts to a denial of the reality of the organic beings which we actually see and deal with (Ritter, 1911, p. 441).
It is plain that at present chemical and physical formulations do not suffice to answer biological questions, do not adequately cover what is distinctive in the functions, behaviour, development, and evolution of living creatures. But this does not in itself prove the validity of any of the various forms of positive vitalism. These must be considered on their merits.
(a) Some have maintained that mechanistic formulation is not exhaustive even within the domain of the inorganic. If so it will be a fortiori inadequate in the realm of organisms. (b) Others, while admitting that we cannot now translate vital processes into terms of any known chemistry and physics, suggest that we may be able to do so eventually. The concepts of chemistry and physics may have to be modified. But we can only discuss the sciences as we know them now. (c) Others, again, maintain that it is mind that makes all the difference. But the problem Vitalism or Mechanism? is the same for plants as for animals, and we do not know anything about the mind of plants.
It may be said that there are three grades of vitalism. (1) The first finds the differentia of organisms in the greater complexity of their configurations or collocations of elementary particles. Living creatures are apart, but they do not require new concepts (an autonomous science) for their description. They only require separate laboratories for their study. (2) The second vitalistic theory holds that organisms have a monopoly of some peculiar physical energy or energies in a line with, say, electricity. (3) The third theorythe only thoroughgoing vitalismpostulates a non-perceptual vital agency, associated with organisms, operating actively in certain cases, directing the chemico-physical processes, so that their results are different from what they would have been apart from intervention. The finest expression of this view is Driesch's doctrine of Entelechy, the advantages and difficulties of which must be carefully considered.
Perhaps it is safer to be content with a descriptive or methodological vitalismthat is, with maintaining that in describing organisms we require ultra-mechanical concepts. But if the word vitalism is taken to imply dualism and intervention, we may call our position simply biological or organismal. The central idea is that of the organism as a psycho-physical individuality which has enregistered within itself the gains of experience and experiment, and has ever its conative bow bent towards the future. Instead of trying to interpolate a new agency, may we not simply recognise that organisms reveal certain aspects of reality which are not apparent in the domain of the inorganic?