It is precisely in the field of immunity that such a machine-like preparation of the adaptive effects seems almost impossible to be imagined. How indeed could there be a machine, the chemical constituents of which were such as to correspond adaptively to almost every requirement?—to say nothing of the fact that the production of more of the protecting substance than is actually necessary could hardly be said to be “chemical.”
In fact, we are well entitled to say that we have reached here the very heart of life and of biology. If nevertheless we do not call the sum of our facts a real proof of vitalism, it is only because we feel unable to formulate the analysis of what happens in such a manner as to make a machine as the basis of all reactions absolutely unimaginable and unthinkable. There might be a true machine in the organism producing immunity with all its adaptations. We cannot disprove such a doctrine by demonstrating that it would lead to a real absurdity, as we did in our analysis of differentiation of form; there is only a very high degree of improbability in our present case. But an indirect proof must reduce to absurdity all the possibilities except one, in order to be a proof.
Mechanistic explanations in all branches of functional physiology proper, so much in vogue twenty years ago, can indeed be said to have failed all along the line: the only advantage they have brought to science is the clearer statement of problems to which we are now accustomed. But we are not fully entitled to say[118] that there never will be any mechanistic explanation of physiological functions in the future. It may seem as improbable as anything can be; but we wish to know not what is improbable but what is not possible.
Now of course you might answer me that after we have indeed shown that the production of form, as occurring on the basis of harmonious-equipotential systems, is a fact that proves vitalism, the acts taking place on the basis of that form after its production would have been proved to be vitalistic also, or at least to be in some connection with vitalistic phenomena. Certainly they would, and I myself personally should not hesitate to say so. But that is not the question. We have to ask: Is any new proof, independent of every other, to be obtained from the facts of physiological adaptation in themselves? And there is really none. Mere regulatory correspondence between stimuli and reactions, even if it be of the adaptive type and occur in almost indefinite forms, never really disproves a machine as its basis so long as the stimuli and reactions are simple and uniform. Next summer, however, we shall see that vitalism may be proved by such a correspondence if the two corresponding factors are not simple and not uniform.
We most clearly see at this point what it really was in our analysis of differentiation that allowed us to extract a real proof of vitalism from it. Not the mere fact of regulability, but certain specific relations of space, of locality, lay at the very foundation of our proof. These relations, indeed, and only these relations, made it possible to reduce ad absurdum any possible existence of a machine as the actual basis of what we had studied. In our next chapter again it will be space-relations, though analysed in a different manner, that will enable us to add a second real proof of vitalism to our first one.
With this chapter we conclude the study of organic regulation in all its forms, as far as morphogenesis and metabolism are in question.
But our analysis of these regulations would be incomplete and indeed would be open to objections, if we did not devote at least a few words to two merely negative topics, which will be taken more fully into consideration later on.
A FEW REMARKS ON THE LIMITS OF REGULABILITY
There has never been found any sort of “experience” in regulations about morphogenesis or in adaptations of the proper physiological type. Nothing goes on “better” the second time than it did the first time;[119] everything is either complete, whenever it occurs, or it does not occur at all.