The establishment of the theory of organic evolution in the middle of the nineteenth century completely reconstructed the biological sciences; it gave a new key to the varieties of life, placed structure and function in a new light, and projected a genetic version of organic processes, as applicable to the highest as to the lowest organisms.

This biological renaissance determined the advance of psychology. Psychology, as we know it, was impossible before Darwin, not because of the evolution concept alone, but because of the confluence of several rapidly growing streams of knowledge and of method at this period.

The renaissance of psychology was launched with the impetus of the greater wave of evolution. Leaving that for the moment, we must focus upon the experimental approach; the two have in common the objective attitude; and if we include the naturalistic viewpoint, the prolific fertility of modern psychology is traced to its headwaters. Negatively, experimental psychology is a protest against armchair assumptions and subjective elaborations in the systematic manner of philosophy or the eclectic temper of literature. Positively, it is a reform in logical method, deriving remotely from the Baconian emphasis on induction - though this alone was not sufficient to direct psychology into scientific channels. The realistic pursuit, forsaking speculation and clinging close to observation, found a radical expression in the positivist program sponsored by Comte, with its direct influence upon English pragmatic thought.

That movement has its center in the problem, persistent from the Greek to the Darwinian naturalists, as to how the affairs of body and mind are related and integrated. When Wundt, the first mind to be inspired by the vision of a comprehensive scientific psychology, came to formulate it in a massive volume, the parent of five-foot and fifty-foot shelves of modern psychological texts, he properly called his systematic treatise "Physiological Psychology." He is known as the father of experimental psychology and the founder of the first psychological laboratory (1879). Though the chair he held, true to the older tradition, was titled "philosophy," he followed the clue of the times in focusing upon the physiological approach.

The first chair in Physiology was established as late as 1833.

Until mental functions, from low to high without exception, are considered in their biological origins and counterparts, a scientific psychology lacks central unity. That is a fundamental relation confirmed by evolution; for bodily and mental functions emerge and evolve by the same set of forces. The mind's heredity and the body's heredity are one. We are not thus curtly disposing of the mystery of mind, not asserting that thoughts and emotions may be reduced to patterns of behavior in the nervous system. But since in many ways we know more of mind than of body, the demonstration of the reality of the connection between the two remains a guiding principle throughout, though we can apply it but partially.

The connection can be suggested in a paragraph; it can be covered only in a volume such as C. Judson Herrick's 'The Thinking Machine."The advancement of physiological psychology from the days of Wundt to those of Herrick is equally striking. A machine the mind is, but of its own type of organization, with only secondary analogies to man-made mechanisms. There is no more hesitation in speaking of one integration of "brain" areas as the organ of consciousness than in speaking of another as correlated with digestion, and another with sex; and both these "physiological"functions may induce elaborate and disturbing "conscious" representations.

The hierarchy of the central nervous system conditions fundamentally and throughout the hierarchy of the mental activities. The simplest member of the series was termed a reflex.1 Here lies the basic unit pattern of response. And 1 It is as true of scientific as of personal names that their baptismal status gives no indication of future career."Reflex" arose from an outdated notion of actual reflection - as of a ray of light from a mirror - but was physiologically conceived with the appearance of the neurone theory and of neuronic integration. Sir Michael with its mention we may as well face the aggressively-contentious issue of behaviorism which holds that at the beginning was the conditioned reflex, and there has been nothing since. In every logical sense the copyrighted "behaviorism" for which John B. Watson claims proprietary rights, filed (presumably in the Library of Congress) in 1912, has no place in a serious and responsible discussion of the origins and tenets of modern psychology. It is included with apologies; but its omission might be misunderstood. The claim that scientific psychology began when the term "consciousness" was dropped and "behavior" substituted, is as false as it is trivial and captious. The turn away from the emphasis on the "rational" processes, detachedly considered, toward the inclusion of all varieties of mental behavior, is a gradually increasing by-product of the naturalistic trend above outlined. It appears in successive waves, the first at least a hundred years ago. With few if any exceptions all modern psychologists are behaviorists.

To charter the word"behaviorism"for one's personal vehicle is an impertinence in one sense or the other. No man of science has any time or taste for the querulous game of logomachy. As for the radical and far-reaching conclusions which Dr. Watson regards as"behavioristic," they belong to the story of the mental vagaries of able minds. It is because his views for a time found a limited following that their mention is warranted as a perturbing incident in the orderly progress of modern psychology.

The study of the reflexes, including the limited order of "conditioned" reflexes with which the serious work of Dr. Watson was concerned, emphasizes the basic importance of primitive, lowly behavior patterns. But the corn-Foster's"History of Physiology, etc." (Cambridge University Press, Cambridge, 1901), takes the story to the point at which the recent reflexology of Pavlov continues it.