The Science and Philosophy of the Organism

Looking back upon the whole of the work done, especially by Jennings, we see that there is nothing very fixed about the most primitive types of animal movement, but something very variable. In some cases we understand the laws and principles of such variability, in others they either do not exist or they escape us by reason of the minuteness of the objects in question. Shall we by adopting the " machine-theory " of life be able to understand all that has been observed regarding the most simple movements ? Most of it, certainly, might be understood in such a manner, at least in principle, and as long as no greater complexity is discovered. But to prove that the fact of so-called " experience " is beyond the limits of such an explanation, will be the object of a special discussion in the future. Of course, as mentioned before, to affirm the possibility of mechanical explanation is not to affirm the impossibility of vitalistic actuality : for methodological reasons we always hold the " machinetheory" of life as long as possible — this theory may be actually wrong even in the apparently most simple phenomena in organisms.

We now leave the work of Herbert Jennings and turn to a short survey of the possible classes of so-called co ordinated motions. Much has long been known about the elemental processes that go on in the nervous system of a moving animal, or, rather, much has been attributed to this system in the form of a so-called " property " or " functional state." For it must be well understood that the immediate subject of experimental study always and in every case has been the state of the motor organs as such ; so-called nervous

states or conditions have been inferred from this study, and, so to say, have been projected upon the nervous system. It was seen that simple nervous conduction would not suffice to explain what happens here, and the word " centre " therefore played a great though rather mysterious role. " Centres " were identified with the anatomical ganglia until Bethe showed that in crabs some typical reflexes may go on even after the ganglia have been extirpated. A certain school of modern physiologists then thought they might drop the concept of a " centre " altogether, but more recently a sort of compromise between the old and the new theory has been come to. The concepts of " inhibition " and " path-making " (" Hemmung," " Bahnung," in German), and the like have been employed to designate elemental conditions of the nervous system, apart from conduction, that are concerned in combined motions.

It seems to me that the system of elemental nervous qualities which von Uexkuell * has lately created may claim to be the most complete and the most original conception in this field. To state in a few words the logical value of von Uexkuell's concepts as relating to the general theory of movement, it seems to me that he has formulated what might be called the elemental "means" in the mutual relation of the motor parts used and con- 1 See especially Leitfadcn in das Studium der expcrimentcllen Biologic der Wassertiere, Wiesbaden, 1905. Von Uexkuell's work is composed of an analytical and of an hypothetical or fictive part ; we only deal here with the former, which is very valuable. This part will retain its value, it seems to me, even if the hydrodynamic and electric hypothesis of "tonus" has to be given up.

cerned in any correlated motion whatever. I should like to parallel his concepts of " tonus," " tonus - reservoir," "blocking," "latching" (" Klinkung "), etc., directly with the elemental concepts of formative stimulus, prospective potency, inner means, etc., in morphogenesis. For, in fact, all the concepts of von Uexkuell are concerned in any co-ordinated movement whatever, though, properly under stood, none of them, of course, says anything about the specificity of co-ordination as such.

Now it is of great importance, that the analytical results of von Uexkuell about the elements concerned in co-ordinated motion are in a most perfect state of harmony with what Jennings discovered about simple motor acts. Let us mention at least a few of the elemental nervous relations revealed by von Uexkuell's work. The type of any single act of a combined movement may be altered by the intensity of the stimulus, or by its quality, or by the introduction of a second simultaneous stimulus, either at the same spot or elsewhere, or by the occurrence of previous stimulations ; and there may be a change in the behaviour regarding the single constituents in consecutive times of their realisation ; and one reacting constituent may be stopped by any other one whatever.

There is hardly one feature in this doctrine of the constituents of combined motion that does not appear in the single motor acts as well. Combined motions thus are far from being a grouping of simple typical reflexes exclusively : most of what was believed to be truly reflex has been proved not to be so.1 1 It must be understood that von Uexkuell himself (see Zeitschrift f. Biol. 50, 1907, p. 168) adheres to the reflex-theory of movement, and that

And now let us glance at the different types or classes of co-ordinated animal motions, always asking at each step, what would be intelligible here on the theory of a machine and what would not. The simplest class — considered logically — of all co ordinated movements is formed by the so-called " chainreflexes," which seem to occur in several groups of Inverte brates ; one typical simple reflex is combined here with a number of others in a fixed way. Either — as in Medusae or in the heart of higher animals — one simple reflex causes the simultaneous performance of many similar equal ones, or the end of the performance of one is the stimulus to the performance of the other, as in the movements of many so-called metameric animals. We may speak of " synchronic " reflexes in the first case and " metachronic " ones in the second. In the jelly-fish all the parts of the " umbrella " move together as soon as one of them has begun movement, and in the earthworm the end of thecontraction of one segment always causes the next one to move. And it may happen that parts of an animal which are dissimilar in organisation may also appear as the single constituents of a metachronic chain-reflex. It is especially to J. Loeb * that much of our knowledge of " chain-reflexes "

both Uexkuell and Jennings are constantly at literary warfare with one another. But it seems to me that this is owing to a mutual misunderstanding. In any case von Uexkuell does not operate with the old concept of " reflex " exclusively ; his important discrimination between two elemental functions of muscles and motor nerves — ordinary contraction and "Sperrung" — would by itself suffice to show that. 1 Comparative Physiology of the Brain and Comparative Psychology, New York, 1900.

is due. Of course these simple phenomena would be perfectly intelligible on the machine-theory. Unfortunately they are not so common as Loeb and others thought them to be. The next class of combined motions, first established by von Uexkuell, already forces us to introduce some other elemental nervous phenomena besides mere stimulation and nervous conduction. This type is seen in the progressive movements of many lower animals, but also, as shown by Sherrington,1 in the move ments of vertebrates, so far as they depend on the spinal cord only. The most simple scheme of the class is expressed by the fact, that every motor stimulation in " simple nerve-nets " always relates to those muscles which are not contracted but extended, whether passively or actively. This scheme of course takes no account of the stimulation, but simply states that, if the stimulation is given and if the organisation of an animal with regard to its muscles is such as it is, the kind of movement is determined in the very simple manner we have mentioned. Many of the rhythmical movements in walking are explained in this way. They depend on the antagonistic character of certain muscles : one muscle has just the opposite effect to another, so that, if the one is contracted, the other is extended ; the latter therefore receives the stimulation and contracts ; then the other extends, is therefore stimulated, contracts, and so on.

Of course there would be no difficulty in understand ing on a purely mechanical hypothesis this simple class of combined movements, in which only one elemental nervous function, besides mere conduction, seems to be at work. But, unfortunately again, the simple scheme fails us, as soon as the limits of mere typical progressive motions are transgressed. The sea-urchin, for instance, very properly follows our law when simply walking, but something very different happens as soon as it is put on its back and has to turn over into its normal position ; all sorts of new elemental functions, relating to the dependence of the different single motor constituents on one another, are playing their part here, just as circumstances require, and the stating of a simple formula becomes an impossibility. The same holds for the turning over of the starfish, in which the successful movements of some of the arms stop the movement of the others, and, indeed, we properly can say, that almost any movement of an animal, in any way deserving the name " abnormal," shows a particular type of motor combination.

The " righting reactions " of the starfish and certain other points of interest form the subject of a recent very important memoir by Jennings (Univ. Calif orn. Pull. Zool. 4, 1907, p. 53). Jennings fully confirms the older results published by Preyer, and adds a good number of new results. Let me mention only a few topics. Asterias was found to avoid obstacles whilst creeping to a certain place in a known environment, but to " explore " every object in new surroundings. The " righting reaction " may show a great many very different types. In each case the initial movement of each single arm is determined separately by external stimuli or internal conditions, but as soon as the least result with regard to righting is reached a " unified impulse "

appears ; co-ordination sets in where incoordination had been, and by no means can every single motor act now be related to a single stimulus, as was the case at the very beginning of the process ; on the contrary, " single " stimuli now cease to have any influence at all ; we may say that the animal is not "distracted" by anything. The " unified impulse " may be based upon a great many different constellations of initial movement of the single arms. It is very important to notice well that the righting reactions are not referable to the " normal " position of the animal as such : this hypothesis is refuted by the fact that during the unified period of the reaction the single arms very often perform movements by which they come into " abnormal " positions themselves, or which are indifferent for their own righting : everything occurs in the service of the whole.

It is true, Jennings has shown that the starfish is capable of a good deal of what is popularly called " experience " ; therefore the righting reaction and other movements of this animal do not properly belong to this chapter. But it seems to me that it was well worth devoting a few words to the discoveries of Preyer and Jennings at this place, as the movements of the starfish have often been looked upon as enormously simple. In \ any case the reactions of the starfish are not " reflexes," but are in the highest degree what on a later occasion

1 I am very glad to see that Jennings himself insists upon the unity of the phenomena observed. He even concedes that my entelechy would explain this unity, though he declines to see here a true " explanation." In this respect I hope that Part II. of Section B will convince him. dependent on the spinal cord are not reflexes in the old sense of the word, but are motor reactions determined by the stimulus and by all that has happened and that is happening in other parts of the moving body, nay, even by the contingency of the actual general arrange ment of the motor organs at a given moment (Sherrington).

The " centres," we are told, store and bind and stop stimulations, and set them free at the right time, and so on. But the word " centre " is only a name here for hypothetic anatomical places, where these processes are supposed to occur. Nothing whatever is explained by the use of this ambiguous word. And now there are still other instances of combined motions of a far greater complexity in style than a simple turning over into the normal position. I am thinking of what is generally known under the name of " instinct." And the last and highest group of combined movements is what is called " action," in which " experience " is at work. What shall we say in the face of all these natural facts ?

I regret that I am unable to give here an accurate and minute analysis of all possible sorts of co-ordinated move ments ; but it seems to me that some special characters at least of the most typical of the higher classes of combined animal motions ought to be subjected to a closer consideration. It may lead at least to a clear conception of the real problems of motor physiology, and perhaps even to somewhat more than that. In the next chapters therefore the typical form of instinct and the typical action will be analysed completely. I shall try to fix, as sharply as possible, what problems may appear in these

two groups of organic movements, and what solutions may be given. Other kinds of complicated movements, which are neither instincts nor actions proper, will form a sort of appendix to one or the other of the two great funda mental groups. We know from our last studies that the elemental processes concerned in animal movements are not only nervous conduction, but may also consist in facts of different kinds which have forced modern authors to make use again of the old word " centre " in a purely physiological sense, after the anatomical meaning of this word had proved to be of rather dubious value for physiological analysis. It is to von Uexkuell that the most thorough analysis of organic movements into their simple components is due, and, in order to express the true logical value of such an analysis, we did not hesitate to compare its results with those furnished us by the analysis of the genesis of form.

But this comparison now has another and very im portant consequence. We saw that form evidently was the result of the arrangement of certain elements, and that all genesis of form could be reduced to the constellation of certain factors concerned in it ; but neither was form a mere sum of those elements nor was its origin the result of a mere sum of these factors. Nothing at all is proved about a totality being a mere sum or not a mere sum by demonstrating the elements it consists of: this holds for form as well as for movements.

As we said, we cannot study here minutely all the varieties of combinations of movement which occur in the animal kingdom. For many of them, it is true, we are able to imagine a machine that would represent how they take place : for the sake of simplicity let us take it for granted that a machine actually exists here, though it is not by any means proved. But are there not cases of combination of movements, most familiar to all of you, for which it is by no means clear from the beginning that a machine even could be present as their foundation ? Are there not at least a few classes of animal movements which common sense daily describes by words which seem to express anything but the conviction that they are simple, mechanical, and machine-like events ?

Itistinct is one of these classes of animal movements, and it is with instinct that our analytical study will have to deal in this chapter. The problem of instinct used to be one of the chief points in the fight between Darwinians and Lamarckians. As we cannot accept either of these theories, it follows that we shall not study instinct from the usual points of view. It may suffice to state here that the specific instincts of the worker-bees, which are excluded from propagation, would never be open to any Lamarckian explanation, as Weismann has most clearly demonstrated ; and on the other hand, every Darwinian explanation fails here for the same general reasons for which it fails in

every explanation of combinations that are typical units. We do not know what the " history " of instincts is, nor do we know the factors concerned in their history. Let us rather try to discover a little about what factors are concerned in instinctive movements as they actually come before us every day. At this point a second problem appears, round which discussion centres nowadays. We shall be forced to decline a limine this problem also, but a certain justification is required for declining it, and as this justification is to rest on an epistemological basis, which is of first-rate importance for all our studies of animal movements in this chapter and the next, a short excursion into philosophy is necessary.

Are instincts " conscious " or " unconscious " movements ? this is the question that is always being discussed at the present day. And yet this problem cannot be a scientific or philosophical problem, at least not if the words " con scious " and " consciousness " are to signify what they usually do. Let us proceed most rigorously with regard to this point. As naturalists we study animal movements as move ments of bodies in Nature, and we can do no more. But the terms " conscious " and " consciousness " do not belong to that part of the Given which we call Nature ; they belong to the Ego, to " my " Ego, and to my Ego exclusively. It is not even possible to express with clearness what is meant by saying that there " is " consciousness in any being in Nature. We are faced here by a pseudo-problem of the purest type.

Other physiologists also have denied the possibility of discovering " consciousness " or " unconsciousness " in the motions of animals. But it almost always was in a practical sense that they spoke of such an impossibility. We under stand it in an epistemological sense. There may be feelings quite unknown to us, such authors have said ; therefore it would be better not to speak about feelings. But we say : the " being " of " feelings in Nature is meaningless altogether. " Being " relates to bodily movements and changes, in that sense of " being " which is the only starting-point of all science, in the sense of " being given to my Ego."

It is true : the concept of " being " may be enlarged by an advanced philosophical science ; we ourselves have enlarged it, and shall do so further on by introducing potentialities as " being." But even such potentialities if conceived as natural agents or factors would never be " consciousness." The word " conscious " belongs to intro spective psychology exclusively. But what about instincts ? How are we to formulate our legitimate and scientific problem ? It seems to me that there can be but little doubt how we are to formulate it. Are those animal movements, commonly called instincts, such that they might be founded on a machine, a physicochemical manifoldness in space, embracing only physicochemical elemental factors, or are there some features in instincts which forbid us to assume the existence of such a machine even hypothetically ?

Let us first try to give a purely verbal definition of the instinctive motions in question. It will prove to be rather difficult to find an under limit of instinct, though it is easy to find an upper one. All instincts are separated from the next higher group of motion, which we propose to call " actions " in the widest sense of the word, by being com plete in their specificity from the very first time they occur. There may be some improvement in consequence of their being repeated, but this improvement never affects their specificity as such. Perhaps it will be more correct to say that we shall not apply the term " instinct " to any animal movement that shows an improvement with regard to its specificity.

Instincts are often said to be " purposeful " with regard to their performer. We prefer to say, at present, that they possess some regulative character ; that they tend to " nor mality " with regard to the whole life of the organism which performs them. Here the limit between instincts and other classes of motions is not always very clearly marked : almost all typically combined motions, be they pure chainreflexes or be they of a more complicated type, are alike in possessing a regulative character. And it is impossible to draw a sharp boundary here, if one has renounced the question of " consciousness " as illegitimate. In fact, all instincts are chains of single nervous acts concerned in movements, just as are real chain-reflexes and many other combined motions : it is only the degree of chaining that comes into account.

But what is the meaning of the word " degree " in this connexion ? Does it apply only to different states of com plication of the same invariable general type ? It is here that our analytical problems begin. Up to about 1890 instincts were studied almost exclu sively from the historical point of view, or with regard to their relation to " consciousness." Jacques Loeb was the first to see the inadequacy of both these methods, and to put the problem of instinct on its clear physiological basis. Unfortunately in doing so Loeb was influenced by the materialistic dogmatism of his time. The single reflex was to him the prototype of all elemental factors concerned in movement, all complex or chain movements were regarded as being of the most simple additive kind, even the compli cations afterwards discussed by von Uexkuell were then unknown. Hence it was possible for Loeb to regard in stincts also as nothing but chain-reflexes of the mere addi tive type. One of the elementary processes composing the instinct was regarded as being the cause of the next one, and so on. The general state of the organism was not neglected in this analysis, and it was well known to Loeb that young animals may show " chain -reflexes " different from those shown by the adult, and that a well-nourished animal may react differently from a hungry animal ; but the different physiological state of the animal in these cases was a priori regarded as being a mere point of its organisa tion in the widest sense, and nervous conduction remained the only physiological element taken as proved ; even socalled " inhibition " was not regarded as a nervous function sui generis.

Thus pseudo-psychological problems yielded to problems of mechanical dogmatism in the physiology of instincts. gained by the work of Loeb, and it is from this point that a purely analytical treatment of the theory of instincts must start. By resolving all instincts into chain-reflexes that as a whole were of the well-known character of " taxis," Loeb implicitly had stated a very important problem in the form of a fact : science in the future will have to find out whether there is any such fact.

If indeed all instincts are of the type of very simple co-ordinated motions, whether that be the most simple and merely additive type or any more complicated one — in short, if all instincts as a whole are of the character of a " taxis," it follows that it only can be the simple and elemental agents in Nature which can act as stimuli to instincts. The stimuli of instinctive movements may be light of different wave-lengths, or heat, or moisture, or chemical compounds, but tliey never are specific typical bodies.