Title of article
E. D. Cope
In order to comprehend the question at issue, it is necessary to state certain fundamental principles of evolution. This process consists in the development of the heterogeneous from the homogeneous as Spencer expresses it; or in more specific language, evolution consists in the development of specialized structures from generalized material. Primitive organic or living beings consist of protoplasm which is, as compared with higher organisms, generalized. That is, they are without distinct muscular, nervous, or digestive organs, etc. How are psychic conditions related to this process of specialization? Prof. Baldwin states that an animal is able to " select through pleasure, pain, experience, association, etc., from certain alternative complex movements which are already possible for the limb or member used." This means that under guidance of a form of consciousness, certain existing muscles are selected to perform certain movements, while other muscles are neglected. Now if this be possible to a muscular system specialized into discrete bundles, it is also possible to a primitive contractile protoplasm which is not yet differ-
(429)-entiated into discrete muscular and other bodies. In other words it is possible to contract that part of the homogeneous protoplasm which is necessary for the production of a certain movement, and leave that part of the protoplasm which is not necessary to produce the movement, uncontracted. And this is exactly what undifferentiated animals (Protozoa) do, and it is what is done at all stages of differentiation of the muscular system, so far as the differentiation which that muscular system has attained, will permit. It is the sentence which I have quoted above from Prof. Baldwin which induced me to say that he admits the Lamarkian factor. For there is no doubt that it has been this habitual contraction of certain parts of undifferentiated protoplasm which has produced muscular bands, sheets, etc., as distinguished from other histological elements of the organism. If this be true, there is no necessity for the hypothesis of "overproduced movements" as the source of new habits, since those habits may be produced by the direct effect of the selective power of the animal over its own protoplasm. It is not intended by this expression to claim anything more than simple sensation for simple forms of life, or that anything higher than hunger, reproduction temperature, etc., constitute their pleasures and pains.
The theory of natural selection from " overproduced movements " as a source of new movements stands on the same basis as all the other theories of natural selection as explanations of the origin of anything new. They are impossible in practice, and inaccurate in logic, since in my opinion, following that of Mr. Darwin, they demand of Natural Selection a function of which it is by its definition incapable. That natural selection regulates the survival of movements after they have originated, goes without saying. It is evident that "overproduced movements" must on Prof. Baldwin's "Organic Selection" theory, include the adaptive one which is destined to survive. The question then is as to the origin of this particular " overproduced " and adaptive movement. The explanation has been given above; i.e. that it is a direct response to the stimulus supplied. The location in the organism of the responsive movement depends on the location of the stimulus, a fact testified to by the close local connection of motor with sensory nerves of general sensation. In the ease of responses to special sensation, we may suppose that the responses only became exact as to locality after a period of trial and error, the new movement always having a local relation to the point of stimulus. The beast bites his wound, before he has traced the pain to his enemy. As already pointed out, this process would result in a perfected mechanism which would be inherited. No one can yet explain the mechanism of the control of a mental state
(430) over a contraction of protoplasm. It is one of the ultimate facts of the universe. When Prof. Baldwin admits that an animal can select which of two muscles it will use, or when he admits that an animal can contract any muscle under the stimulus of "pleasure, pain, etc., he admits this ultimate fact, but does not explain it.
As to the scope of Social Heredity as a factor in psychic evolution, it appears to me to be, like that of the higher intelligence, mainly restricted to the higher animals and to man. Maternal instruction among all but the higher animals probably has no existence. Imitation may be supposed to be possible to animals a little lower in the scale. But both factors are to my mind only supplementary to the more vigorous education furnished by the environment with its wealth of stimuli to " pleasure, pain, experience, association, etc." In regarding Social Heredity as the sole factor of psychic evolution, Prof. Baldwin temporarily loses sight of the intimate connection between mind and its physical basis. The inheritance of mental characteristics is as much a fact as the inheritance of physical structure, and for the reason that the two propositions are identical. One does not believe in either education or imitation as a cause of the repetition of insanity in family lines. We rather believe in a defective brain mechanism, which is inheritable, through fortunately not always inherited. The doctrine of Weismann that acquired characters are not inherited, if true, would furnish the physical conditions for the theory that Social Heredity is the only psychic heredity, but it is impossible to believe that Weismann's doctrine is true. Hence while Social Heredity is true as far as it goes, Lamarkism is also true, and expresses the more fundamental law. The fact that no adequate physical explanation of the inheritance of acquired characters has been reached does not disprove the fact.