Social and Ethical Interpretations in Mental Development
SOCIAL HEREDITY AND ORGANIC EVOLUTION
THE conclusions reached in the course of this essay are consistent with a point of view from which a series of considerations on organic evolution in general come to present themselves. The problems involved in the theory of organic development fall under three heads: those in Ontogeny (or individual development), Phylogeny (or race development), and Heredity. The general method of personal adaptation which, in the social sphere, we have called 'social heredity' extends to the lower forms of life also; giving a view of determinate progress in evolution due to social modes of life. I shall accordingly speak first of its influence in Ontogeny, second in Phylogeny, and third in Heredity.
I. Ontogeny or Individual Development
As long as we are speaking of creatures with consciousness enough to learn by imitation, and so to come under the principle of ' social heredity,' it is plain that certain results will follow as regards these creatures themselves in consequence of their adaptations.
1. By securing adaptations or accommodations, in special circumstances such as those of a social kind, the creature may be kept alive in the struggle for existence. This influence has been pointed out in a great variety of animal species by various writers (Wallace, Weismann, Lloyd Morgan, Hudson).
2. By this means those congenital variations which lend themselves to intelligent, imitative, and social accommodation during the lifetime of the creatures, are screened from the action of natural selection and are so kept in existence. Other congenital variations are not kept thus in existence. So there arises, partly through the elimination of those individuals which cannot make the accommodations, a widespread series of apparently determinate variations (i.e., having a definite direction) in each generation.
3. The same principle secures these two results, also. wherever the creature secures adaptations during his private life for whatever reason. Conscious and social accommodation is not, of course, the only sort. There are three different sources of modifications in biological organ-
(546) -isms. There are: first, the physical agencies in the environment, which produce modifications of the creature's form and functions. They include chemical agents, strains, contacts; hindrances to growth, temperature changes, etc. Second, modifications of function and structure arise from the activities of the organism itself under the law of use and disuse. This class of modifications is seen in a remarkable way in plants (Henslow, Sachs, Pfeffer), and in microorganisms (Bunge, Loeb), which show the sort of adaptation called the selective property' by such writers as Romanes. And, third, there are the intelligent, imitative, and social adaptations which are spoken of above, and which show the clear operation of the principle of 'social heredity.'
All these influences serve to effect modifications of an adaptive kind in the creature, during its lifetime ; so make it more available for continued life under the operation of the principle of natural selection ; and thus secure the great end of setting a determinate direction in the generation which these creatures represent. So much for our conclusion in the matter of ontogeny.
II. Phylogeny or Race Evolution
Certain results, in the province of phylogeny, flow directly from the preservation of creatures which accommodate themselves socially or otherwise.
First. The congenital variations of subsequent generations are distributed about the mean represented by the creatures preserved through accommodation in the earlier generations. Of course this must follow from the doctrine that the characters of the offspring vary about a mean between the characters of the parents. If the parents have been kept alive just because they secured a certain form of adaptation, then their children will be so endowed as to secure the same adaptation. So a determinate direction—the same as that of ontogenetis—is given to phylogenetic evolution. In the case of social accommodation the later generations will tend to greater sociality.
Second. The mean of congenital variation being thus made more determinate, further congenital variations follow about this mean, and these variations are again utilized for further ontogenetic adaptation. So there is continual progress in the directions set by ontogenetic adaptations ; and, in the case of social adaptations. in social lines.
Third. This will be the case purely through physical heredity, which will thus be brought more and more into accord with the direction of social heredity.
This influence I have called 'organic selection.' It has certain bearings upon the theories of hereditary transmission. The constant determination of the mean of variations, and through it also that of the direction of phylogenetic evolution, gives two great converging channels of hereditary influence without appeal to the Lamarckian principle of the inheritance of acquired characters.'
First. It gives determinate direction to organic evolution without the direct inheritance of acquired characters, since it shifts the mean of variations in the young in the direction of the characters acquired by the parents, and so produces the same results as if these characters had been actually inherited.
Second The operation of 'social heredity' secures the transmission of the acquisitions of an intelligent and social kind, without the intervention of physical heredity at all. So it keeps alive a series of functions —as, for example, speech—which never do become congenital; or it keeps them alive until by the operation of organic selection they do become congenital. The general co-operations called social are of this kind; and the method of their transmission 'as detailed actions' is exclusively that of 'social heredity.'
Third. These two influences, 'organic selection' and 'social heredity,' operate in a parallel way in all creatures of much biological organization.
Fourth. This general influence of individual accommodation, whether social or otherwise, in setting the direction of subsequent evolution under natural selection, has been fully described under the phrase 'organic selection,' in earlier publications.