Science and Morals and Other Essays, Sir Windle Bertram Coghill Alan [reading books for 7 year olds .TXT] 📗

"The idea that the organism as a whole cannot be explained from a physico-chemical viewpoint rests most strongly on the existence of animal instincts and will. Many of the instinctive actions are 'purposeful,' i.e. assisting to preserve the individual and the race. This again suggests 'design' and a designing 'force,' which we do not find in the realm of physics. We must remember, however, that there was a time when the same 'purposefulness' was believed to exist in the cosmos where everything seemed to turn literally and metaphorically around the earth, the abode of man. In the latter case, the anthropo- or geo-centric view came to an end when it was shown that the motions of the planets were regulated by Newton's law, and that there was no room left for the activities of a guiding power. Likewise, in the realm of instincts, when it can be shown that these instincts may be reduced to elementary physico-chemical laws, the assumption of design becomes superfluous." (Italics mine.)

In the first place the "purposefulness" of the movements of the planets is not affected in the very least by the question of heliocentricism. What the author is probably thinking of is an exaggerated and obsolete teleology, but that is not what seems to be the purport of the passage. Let that pass. The main confusion lies in the application of the term "Law." The Ten Commandments, and our familiar friend D.O.R.A., are laws we must obey or take the consequences of our disobedience. The "laws" which the writer is dealing with are not anything of this kind. Newton's Law is not a thing made by Newton, but an orderly system of events which was in existence long before Newton's time, but was first demonstrated by him. It tells us how a certain part of the system works—when we are "inside it." It does not in the least explain the system any more than the discovery of the resiliency of the spring of the watch explains the watch itself. So far from dispensing with "the activities of a guiding power," Newton's law is positively clamant for a final explanation, since it does not tell us, nor does it pretend to tell us, how the "law" came into existence, still less how the planets came to be there, or how they happen to be in a state of motion at all. Writers of this kind never seem to have grasped the significance of such simple matters as the different kinds of causes, or to be aware that a formal cause is not an efficient cause, and that neither of them is a final cause. Coming to the latter part of the paragraph, it is in no way proved that instincts can be reduced to physico-chemical laws, and, suppose it were proved, the assumption of design would be exactly where it is at this moment. It is the old story of St. Thomas Aquinas and Avicenna and their discussion on abiogenesis, and surely biologists might be expected to have heard of that. The same confusion of thought is to be met with elsewhere in this book, and in other similar books, and a few instances may now be examined.

Samuel Butler, in Life and Habit, warns his readers against the dicta of scientific men, and more particularly against his own dicta, though he made no claim to be a scientist. If his reader must believe in something, "let him believe in the music of Handel, the painting of Giovanni Bellini, and in the thirteenth chapter of St. Paul's first Epistle to the Corinthians." And he exclaims: "Let us have no more 'Lo, here!' with the professor; he very rarely knows what he says he knows; no sooner has he misled the world for a sufficient time with a great flourish of trumpets than he is toppled over by one more plausible than himself." That is a somewhat unkind way of putting it; but undoubtedly theory after theory is put forward, and often claimed to be final, only to disappear when another explanation takes its place. Thus at the moment we are in the full flood of the chemical theory which is employed to explain inheritance. That heredity exists we all know, but so far we know nothing about its mechanism. Darwin, with "Pangenesis," and others, using other titles, argued in favour of a "particulate" explanation, but the number of particles which would be necessary to account for the phenomena involved, this and other difficulties, have practically put this explanation out of court. Then we had the Mnemic theory of Hering, Butler, and others, by which the unconscious memory of the embryo—even the germ—is the explanation. Quite lately the mnemic theory has been claimed by Rignano in his Scientific Synthesis as a complete explanation, in forgetfulness of the fact that even the all-powerful protozoon can only remember what has passed and could certainly not remember that it was some day going to breed a man. At the moment, things are explained on a chemical basis, though that basis is far from firm; is of a shifting nature, and a little hazy in details. Some time ago, colloids were the cry. A President of the British Association almost led one to imagine that "the homunculus in the retort" might be expected in a few weeks. But the chemists would have none of this, and denied that the colloids, about which they ought to know more than do the biologists, had that promise in them which had been claimed. We had Leduc and his "fairy flowers," as now we have Loeb and others with their metabolites and hormones. As to these last, there seems to be no kind of doubt that the internal secretions of many organs and structures have effects which were, even a few years ago, quite unsuspected. Those of the thyroid and adrenals are excellent examples.

It seems to be the fate, however, of all supporters of new theories to run into extravagances. Darwin had to remind his enthusiastic disciples that Natural Selection could not create variations, and we may feel some confidence that Hering, were he alive, would urge his followers to bear in mind that memory cannot create a state of affairs which never existed. So far we may certainly say that these internal secretions do produce certain physical effects, some of them effects not to be suspected by the uninformed reader. There seems to be very good evidence that the growth of antlers in deer depends upon an internal secretion from the sex-gland and from the interstitial tissue of that gland; for it is apparently upon the secretions of this portion of the gland that the secondary sexual characters depend, and not merely these, but also the normal sexual instincts. And this takes us a stage further. The extreme claim is that all instincts, in fact all thoughts and operations, are in the last analysis chemical or chemico-physical. Let us examine this claim for a moment. The adrenals are two inconspicuous ductless bodies situated immediately above the kidneys. Not many years ago, when the present writer was a medical student, all that was known about these organs was that when stricken with a certain disease, known as Addison's disease from the name of its first describer, the unfortunate possessor of the diseased glands became of a more or less rich chocolate colour. To-day we know that the internal secretion of these organs is a very powerful styptic, and there is good reason to believe that a copious discharge accompanies an unusual exhibition of rage. When we are told things of this kind we must first of all remember that the adrenalin does not cause the rage, though it may produce its concomitant phenomena. If a man flies into a violent passion because someone has trodden upon his corns, and there is a copious flow of adrenalin from the glands, it is not that flow which has caused his rage. It may be the flow from the interstitial tissue of the sex-glands which engenders sexual feelings, but then those are almost wholly physical, and only in a very minor sense—if even if any true sense—psychical. Persons who take the extreme view have never yet suggested that there is a characteristic hormone connected with those psychical attributes alluded to in the chapter of the Corinthians recommended to our notice by Butler. In fact they seem to ignore all but the lower or vegetable characters when dealing with psychology from the chemico-physical point of view.

Finally, we come again to the fatal and fundamental defect of this as of other "explanations"; it is an explanation "within the system," and therefore unphilosophical in so far as it fails to explain the facts through their ultimate or deepest reasons.

A large part of Loeb's book is devoted to a description of the author's remarkable experiments in artificial parthenogenesis, and an attempt to show that they offer a complete explanation. Sir William Tilden, one of the greatest living authorities on organic chemistry, tells us that "too much has been made of the curious observations of J. Loeb and others"; and he definitely states that when we consider "the propagation of the animal races by the sexual process ... there can be no fear of contradiction in the statement that in the whole range of physical and chemical phenomena there is no ground for even a suggestion of an explanation." Behind this pronouncement of an expert, one might well shelter oneself; but the question under consideration merits a little further treatment. The reproduction of kind, though usually a bi-sexual process, may, however, normally in rare cases be uni-sexual, and this process is known as Parthenogenesis. Even in human beings certain tumours of the sex-glands, known as teratomata, very rare in women and even rarer, if ever existent, in men, have been claimed as examples of attempts at parthenogenesis, and so far no better explanation is available.

Now Loeb and others have succeeded in certain forms—even in a vertebrate like the frog—in inducing development in unimpregnated ova. The evidence for all these things is still slender; but we will content ourselves with noting that point and passing on to the consideration of the phenomena and the claims put forward in connection with them. We find the task of unravelling the writer's meaning rendered more difficult by a certain confusion in his use of terms, since fertilisation, i.e. syngamy—the union of the different sex products—seems to be confused with segmentation, i.e. germination; and this confusion is accentuated by the claim that "the main effect of the spermatozoon in inducing the development of the egg consists in an alteration in the surface of the latter which is apparently of the nature of a cytolysis of the cortical layer. Anything that causes this alteration without endangering the rest of the egg may induce its development." When the spermatozoon enters the ovum it causes some alteration in the surface membrane of the latter which, amongst other things, prevents the entrance of further spermatozoa. Loeb thinks that in causing this alteration it sets up the segmentation of the ovum. That there is a close connection between the two events seems undoubted; that they are in relation of cause and effect seems likely. It is quite evident