Part 11 (1/2)
The reaction from the one-sided mechanical theories shows itself in many different ways and degrees. It may, according to the individual naturalist, affect the theory as a whole, or only certain parts of it, or only particular lines. It starts with mere criticism and with objections, which go no further than saying that ”in the meantime” we are still far from having reached a physico-chemical solution of the riddle of life; it may ascend through all stages up to an absolute rejection of the theory as an idiosyncrasy of the time which impedes the progress of investigation, and as an uncritical prejudice of the schools. It may remain at the level of mere protest, and content itself with demonstrating the insufficiency of the mechanical explanation, without attempting to formulate any independent theory for the domain of the vital; or it may construct a specifically biological theory, claiming independence amid other disciplines, and basing this claim on the autonomy of vital processes; or it may widen out deliberately into metaphysical study and speculation.
Taken at all these levels it presents such a complete section of the trend of modern ideas and problems that it would be an attractive study even apart from the special interest which attaches to it from the point of view of religious and idealistic conceptions of the universe.
Both Liebig and Johannes Muller remained vitalists, notwithstanding the discovery of the synthesis of urea and the increasing number of organic compounds which were built up artificially by purely chemical methods. It was only about the middle of the last century that the younger generation, under the leaders.h.i.+p, in Germany, of Du Bois-Reymond in particular, went over decidedly to the mechanistic side, and carried the doctrines of the school to ever fresh victories. But opposition was not lacking from the outset, though it was restrained and cautious.
Virchow's ”Caution”.
Here, as also in regard to ”Darwinism,” which was advanced about the same time, the typical advocate of ”caution” was Rudolf Virchow. His doubts and reservations found utterance very soon after the theory itself had been promulgated. In his ”Cellular Pathologie,”(76) and in an essay on ”The Old Vitalism and the New,”(77) he puts in a word for a _vis vitalis_. The old vitalism, he declared, had been false because it a.s.sumed, not a _vis_, but a _spiritus vitalis_. The substances in animate and in inanimate bodies have undoubtedly absolutely the same properties. Nevertheless, ”we must at once rid ourselves of the scientific prudery of regarding the processes of life solely as the mechanical result of the molecular forces inherent in their const.i.tuent bodily parts.” The essential feature of life is a derived and communicated force _additional_ to the molecular forces.
Whence it comes we are not told. He glided all round the problem with plat.i.tudinarian expressions, which were intended to show his own adherence as a matter of course to the new biological school, and which revealed at the same time his striking incapacity for defining a problem with any precision. At a ”certain period in the evolution of the earth” this force arose, as the ordinary mechanical movements ”swung over” into the vital.
But it is thus a special form of movement, which detaches itself from the great constants of general movement, and runs its course alongside of, and in constant relation to, these. (Did ever vitalist a.s.sert more?) After thus preparing the way for a return of the veering process at a particular stage of evolution, and giving the necessary a.s.surances against the ”diametrically opposed dualistic position,” Virchow employs almost all the arguments against the mechanical theory which vitalists have ever brought forward. Even the catalytic properties of ferments are above the ”ordinary” physical and chemical forces. The movement of crystallisation, too, cannot be compared with the vital movement. For vital force is not immanent in matter, but is always the product of previous life.(78) In the simplest processes of growth and nutrition the _vis vitalis_ plays its vital _role_. This is true in a much greater degree of the processes of development and morphogenesis. In the phenomena of irritability life reveals its spontaneity through ”responses,” and so on. ”Peu d'anatomie pathologique eloigne du vitalisme, beaucoup d'anatomie pathologique y ramene.”
It is impossible to make much of this position. It leaves the theory with one of the opposing parties, the practice with the other, and the problem just where it was before.
Preyer's Position.
Along with Virchow, we must name another of the older generation, the physiologist William Preyer, who combated ”vitalism,” ”dualism,” and ”mechanism” with equal vehemence, and issued a manifesto, already somewhat solemn and official, against ”vital force.” And yet he must undoubtedly be regarded as a vitalist by mechanists and vitalists alike.(79) He is more definite than Virchow, for he does not content himself with general statements as to the ”origin” of vital force, and of the ”swinging over”
of the merely mechanical energies into the domain of the vital, but holds decidedly to the proposition _omne vivum e vivo_. He therefore maintains that life has always existed in the cosmos, and entirely rejects spontaneous generation.
The fallacy, he says, of the mechanistic claims was due to the increasing number of physical explanations of isolated vital phenomena, and of imitations of the chemical products of organic metabolism. A wrong conclusion was drawn from these. ”Any one who hopes to deduce from the chemical and physical properties of the fertilised egg the necessity that an animal, tormented by hunger and love must, after a certain time, arise therefrom, has a pathetic resemblance to the miserable manufacturers of homunculi.” Life is one of the underivable and inexplicable fundamental functions of universal being. From all eternity life has only been produced from life.
As Preyer accepts the Kant-Laplace theory of the origin of our earth from the sun, he reaches ideas which have points of contact with the ”cosmo-organic” ideas of Fechner. Life was present even when the earth was a fiery fluid sphere, and was possibly more general and more abundant then than it is now. And life as we know it may only be a smaller and isolated expression of that more general life.(80)
Among the younger generation of specialists, those most often quoted as opponents of the mechanical theory are probably Bunge, Rindfleisch, Kerner von Marilaun, Neumeister and Wolff. A special group among them, not very easy to cla.s.sify, may be called the Tectonists. a.s.sociated with them is Reinke's ”Theory of Dominants.” Driesch started from their ranks, and is a most interesting example of consistent development from a recognition of the impossibilities of the mechanistic position to an individually thought-out vitalistic theory. Hertwig, too, takes a very definite position of his own in regard to these matters. Perhaps the most original contribution in the whole field is Albrecht's ”Theory of Different Modes of Regarding Things.” We may close the list with the name of K. C.
Schneider, who has carried these modern ideas on into metaphysical speculation. Several others might be mentioned along with and connecting these representative names.(81)
The Position Of Bunge and Other Physiologists.
For a long time one of the most prominent figures in the controversy was Prof. G. Bunge, of Basle, who was one of the first modern physiologists to champion vitalism, and who has tried to show by a.n.a.logies and ill.u.s.trations what is necessarily implied in vital activity.(82) The mechanical reduction of vital phenomena to physico-chemical forces, he says, is impossible, and becomes more and more so as our knowledge deepens. He brings forward a series of convincing examples of the way in which apparent mechanical explanations have broken down. The absorption of the chyle through the walls of the intestine seemed to be a mechanically intelligible process of osmosis and diffusion. But in reality it proves to be rather a process of selection on the part of the epithelial cells of the intestine, a.n.a.logous to the selection and rejection exercised elsewhere by unicellular organisms. In the same way the epithelial cells of the mammary glands ”select” the suitable substances from the blood. It is impossible to explain in a mechanical way the power which directs the innumerable different chemical and physical processes within the organism, whether they be the bewilderingly purposeful reactions in the individual life of the cell, which seem to point to psychic processes within the plasm, or the riddles of development and of inheritance in particular; for how can a spermatozoon, so small that 500 millions can lie on a cubic line, be the bearer of all the peculiarities of the father to the son?
In Lecture III. Bunge defines his att.i.tude towards the law of the conservation of energy. In so doing he unconsciously follows the lines laid down by Descartes. All processes of movement and all functions exhibited by the living substance are the results of the acc.u.mulated potential energies, and the sums of work done and energy utilised remain the same. But the liberation and the direction of these energies is a factor by itself, which neither increases nor diminishes the sum of energies. ”_Occasiones_” and ”_causae_” are brought into the field once more. The energies effect the phenomena, but they require ”_occasiones_”
to liberate them-thus a stone may fall to the ground by virtue of the potential energies stored in it at the time of its suspension, but it cannot fall until the thread by which it hangs has been cut. The function of the ”_occasio_” itself is something quite outside of and without relation to the effect caused; it is a matter of indifference whether the thread be cut gently through with a razor or shot in two with a cannon ball.
Ka.s.sowitz(83) is an instructive example of how much the force of criticism has been recognised even by those occupying a convinced mechanical point of view. He subjects all the different theories which attempt to explain the chief vital phenomena in mechanical terms to a long and exhaustive examination. The theories of the organism as a thermodynamic engine, osmotic theories, theories of ferments, interpretations in terms of electro-dynamics and molecular-physics-are all examined (chap. iv.); and the failure of all these hypotheses, notwithstanding the enormous amount of ingenuity expended in their construction, is summed up in an emphatic ”_Ignoramus_.” ”The failure is a striking one,” and it is frankly admitted that, in strong contrast to the earlier mood of confident hope, there now prevails a mood of resignation in regard to the mechanical-experimental investigation of the living organism, and that even specialists of the first rank are finding that they have to reckon again seriously with vital force. This breakdown and these admissions do not exactly tend to prejudice us in favour of the author's own attempt to substantiate new mechanical theories.
In the comprehensive text-book of physiological chemistry by R.
Neumeister, the mechanical standpoint seemed to be adhered to as the ideal. But the same writer forsakes it entirely, and disputes it energetically in his most recent work, ”Betrachtungen uber das Wesen der Lebenserscheinungen”(84) (”Considerations as to the Nature of Vital Phenomena”). He pa.s.ses over all the larger problems, such as those of development, inheritance, regeneration, and confines himself in the main to the physiological functions of protoplasm, especially to those of the absorption of food and metabolism. And he shows, by means of ill.u.s.trations, in part Bunge's, in part his own, and in close sympathy with Wundt's views, that even these vital phenomena cannot possibly be explained in terms of chemical affinity, physical osmosis, and the like.
In processes of selection (such as, for instance, the excretion of urea and the retention of sugar in the blood), the ”aim is obvious, but the causes cannot be recognised.” Psychical processes play a certain part in the functions of protoplasm in the form of qualitative and quant.i.tative sensitiveness. All the mechanical processes in living organisms are initiated and directed by psychical processes. Physical, chemical and mechanical laws are perfectly valid, but they are not absolutely dominant.
Living matter is to be defined as ”a unique chemical system, the molecules of which, by their peculiar reciprocal action, give rise to psychical and material processes in such a way that the processes of the one kind are always causally conditioned and started by those of the other kind.” The psychical phenomena he regards as transcendental, supernatural, ”mystical,” yet unquestionably also subject to a strict causal nexus, although the causality must remain for ever concealed. Starting from this basis, he a.n.a.lyses and rejects the explanations which have been offered in terms of the a.n.a.logy of ferments, enzymes, or catalytic processes. In particular, he disputes Ostwald's ”Energismus” and Verworn's Biogen hypothesis.(85)
Among the vitalists of to-day, one of the most frequently cited, perhaps, except Driesch the most frequently cited, is G. Wolff, a _Privatdozent_, formerly at Wurzburg, now at Basle. He has only published short lectures and essays, and these deal not so much with the mechanical theory as with Darwinism.(86) But in these writings his main argument is that of his concluding chapter: the spontaneous adaptiveness of the organism, which nullifies all contingent theories to explain the purposiveness in ontogeny and phylogeny. And in his lecture, ”Mechanismus und Vitalismus,”(87) in which he directs his attention especially to criticising Butschli's defence of mechanism, the only problem to which prominence is given is the one with which we are here concerned. In spite of their brevity, these writings have given rise to much controversy, because what is peculiar to the two standpoints is described with precision, and the problem is clearly defined. His criticism had its starting-point in, and received a special impulse from an empirical proof, due to a very happy experiment of his own, of the marvellous regenerative capacity, and the inherent purposive activity of the living organism. He succeeded in proving that if the lens of the eye of the newt be excised, it may be regrown. The importance of this fact is greatly increased if we trace out in detail the various impossible rival mechanical interpretations which have grown up around this interesting case. As Driesch says, ”It is not a restoration starting from the wound, it is a subst.i.tution starting from a different place.”