As far as the inheritance of truly adaptive characters comes into account—that is, the inheritance of characters which are due to the active faculty of adaptation possessed by the organism, bearing a vitalistic aspect throughout—hardly anything could be said against Lamarckism, except that inheritance of acquired characters is still an hypothesis of small and doubtful value at present. But that specific organisation proper is due to contingent variations, which accidentally have been found to satisfy some needs of the individual and therefore have been maintained and handed down, this reasoning is quite an impossibility of exactly the same kind as the argument of Darwinism.
The process of restitution, perfect the very first time it occurs, if it occurs at all, is again the classical instance against this new sort of contingency, which is assumed to be the basis of transformism. Here we see with our eyes that the organism can do more than simply perpetuate variations that have occurred at random and bear in themselves no relation whatever to any sort of unit or totality. There exists a faculty of a certain higher degree in the organism, and this faculty cannot possibly have originated by the process which Lamarckians[156] assume. But if their principle fails in one instance, it fails as a general theory altogether. And now, on the other hand, as we actually see the individual organism endowed with a morphogenetic power, inexplicable by Lamarckism, but far exceeding the organogenetic faculty assumed by that theory, would it not be most reasonable to conclude from such facts, that there exists a certain organising power at the root of the transformism of species also, a power which we do not understand, which we see only partially manifested in the work of restitutions, but which certainly is not even touched by any of the Lamarckian arguments? There does indeed exist what Gustav Wolff has called primary purposefulness (“primäre Zweckmässigkeit”), at least in restitutions, and this is equally unexplainable by Darwinism and by the dogmatism of the Lamarckians.
But before entering into this area of hypothesis, let us mention a few more objections to be made to the theory of the contingency of form as put forward by Lamarckians. In the first place, let us say a few words about the appropriateness of the term “contingency” as used in this connection. The forms are regarded as contingent by Lamarckians inasmuch as the variations which afterwards serve as “means” to the “needs” of the organism occur quite accidentally with regard to the whole organism. It might be said that these “needs” are not contingent but subject to an inherent destiny, but this plea is excluded by the Lamarckians themselves, when they say that the organism experiences no need until it has enjoyed the accidental fulfilment of the same. So the only thing in Lamarckian transformism which is not of a contingent character would be the psychological agent concerned in it, as being an agent endowed with the primary power of feeling needs after it has felt fulfilment, and of judging about what the means of future fulfilment are, in order to keep them whenever they offer. But these are characteristics of life itself, irrespective of all its specific forms, which alone are concerned in transformism. Now indeed, I think, we see as clearly as possible that Darwinism and Lamarckism, in spite of the great contrast of materialism and psychologism, shake hands on the common ground of the contingency of organic forms.
The whole anti-Darwinistic criticism therefore of Gustav Wolff for instance, may also be applied to Lamarckism with only a few changes of words. How could the origin of so complete an organ as the eye of vertebrates be due to contingent variations? How could that account for the harmony of the different kinds of cells in this very complicated organ with each other and with parts of the brain? And how is it to be understood, on the assumption of contingency, that there are two eyes of almost equal perfection, and that there are two feet, two ears? Islands and mountains do not show such symmetry in their structures.
We shall not repeat our deduction of the origin of restitutions, of regeneration for instance, on the dogmatic Lamarckian theory. As we have said already, it would lead to absurdities as great as in the case of dogmatic Darwinism, and indeed we already have mentioned that Lamarckians would hardly even attempt to explain these phenomena. It follows that dogmatic Lamarckism fails as a general theory about form.[157]
There is finally one group of facts often brought forward against Lamarckism by Darwinian authors[158] which may be called the logical experimentum crucis of this doctrine, an experimentum destined to prove fatal. You know that among the polymorphic groups of bees, termites, and ants, there exists one type of individuals, or even several types, endowed with some very typical features of organisation, but at the same time absolutely excluded from reproduction: how could those morphological types have originated on the plan allowed by the Lamarckians? Of what use would “judgment” about means that are offered by chance and happen to satisfy needs, be to individuals which die without offspring? Here Lamarckism becomes a simple absurdity, just as Darwinism resulted in absurdities elsewhere.
We were speaking about dogmatic Darwinism then, and it is about dogmatic Lamarckism that we are reasoning at present; both theories must fall in their dogmatic form, though a small part of both can be said to stand criticism. But these two parts which survive criticism, one offered by Lamarck, the other by Darwin, are far from being a complete theory of transformism, even if taken together: they only cover a small area of the field concerned in the theory of descent. Almost everything is still to be done, and we may here formulate, briefly at least, what we expect to be accomplished by the science of the future.
4. The Real Results and the Unsolved Problems of Transformism
What has been explained to a certain extent by the two great theories now current is only this. Systematic diversities consisting in mere differences as to intensity or number may perhaps owe their origin to ordinary variation. They may at least, if we are entitled to assume that heredity in some cases is able to hand on such variations without reversion, which, it must be again remarked, is by no means proved by the facts at present. Natural selection may share in this process by eliminating all those individuals that do not show the character which happens to be useful. That is the Darwinian part of an explanation of transformism which may be conceded as an hypothesis. On the other side, congenital histological adaptedness may be regarded hypothetically as due to an inheritance of adaptive characters which had been acquired by the organism’s activity, exerted during a great number of generations. That is the Lamarckian part in the theory of descent.