observed phenomena in the principles of psychology. In several parts of the globe, and most prominently in parts of South America, the aborigines practise a custom known as the ‘couvade’, which forces the father of a new-born child to subject himself to a period of inactive confinement and a series of rigorously observed dietary and other regulations. Let us, for the sake of bringing out the point in high relief, ignore all historical considerations and concentrate exclusively on the subjective elements involved. Whence, then, this strange and wholly irrational association of ideas between fatherhood and a group of taboos? Now the subject of the association of ideas occupies hundreds of pages in psychological literature, yet all this, in itself valuable enough, material has no bearing on our problem, because it is again far too general. We do not doubt for a moment that the association we desire to have illuminated is due either to contiguity or to a perceived similarity of ideas, but why have we this particular association instead of the limitless multitude of associations that would be equally intelligible by the same formulae?

Again, many aboriginal tribes of Australia are subdivided into two halves, membership in which is inherited through the father, in some cases, through the mother in others. These moieties are what is technically called ‘exogamous’, i.e., marriage with a fellow-member is strictly forbidden. The regulation is, indeed, so stringent, the feeling of horror evoked by a transgression so violent, that in former times offenders were promptly put to death. This sentiment is so strong that even when visiting a remote tribe, perhaps a hundred miles away, where there is no possibility of blood-kinship, an Australian will avoid marriage with a member of the moiety bearing the same name as his own. Here, surely, there is matter for psychology. An Australian has a violent emotional reaction akin to our aversion to incest, and may translate his feelings into the most violent action. Or, looking at the matter from another angle, the Australian exercises an admirable self-control, eschewing on principle marital relations with half the women of his community. Yet all that psychologists tell us of the ethical feelings and the will leaves the problem before us wholly untouched. Why this particular curious feeling developed, what place it occupies in mental life, the psychologist fails to explain. We get, again, simply general formulæ about feeling and will that are equally applicable to the case of a man’s beating his wife or a boy’s resisting the temptations of a lollypop. And this, it must be noted, is dealing with the distinctively psychological aspect of the data. Whether the rule in question originated in a common center and thence spread to other tribes, is also a cultural question of great importance, and this historical phase of the subject psychology is avowedly incompetent to deal with. Psychology, then, fails throughout to supply us with the interpretation we want. It is as impotent to reduce to really interpretative psychological principles the subjective aspect of cultural phenomena as it is to explain the historical sequence of events.

It is not necessary to multiply examples to establish the point. It is clear that cultural phenomena contain elements that cannot be reduced to psychological principles. The reason for the insufficiency is already embodied in Tylor’s definition of culture as embracing ‘capabilities and habits acquired by man as a member of society’. The science of psychology, even in its most modern ramifications of abnormal psychology and the study of individual variations, does not grapple with acquired mental traits nor with the influence of society on individual thought, feeling and will. It deals on principle exclusively with innate traits of the individual. Now, whether the sharp separation assumed here between the innate and the acquired, between individual activity as determined by uniquely individual potentialities and as determined by social environment, can be made in practice or not, one thing is clear: there are phenomena that are acquired and in no sense innate, that are socially and not individually determined. When a Christian reacts in a definite way to the perception of a cross, it is clearly not because of an individual psychic peculiarity, for other Christians react in the same way. On the other hand, we are not dealing with a general human trait since the reactions of a Mohammedan or a Buddhist will be quite different. Innumerable instances of this sort show that individual thought, feeling and volition are co-determined by social influences. In so far forth as the potency of these social factors extends we have culture; in so far forth as knowledge, emotion, and will are neither the result of natural endowment shared with other members of the species nor rest on an individual organic basis, we have a thing sui generis that demands for its investigation a distinct science.

Does it follow from the foregoing that there is no possible relation between psychology and culture, that psychological results are a matter of utter indifference to the ethnologist? In their desire to vindicate for their own branch of knowledge a place in the sun, some ethnologists have come very near, if they have not actually reached such a conclusion. To me the case appears in a somewhat different light. Whatever division of labor may be desirable for the economy of scientific work, knowledge as a whole knows nothing of watertight compartments. Further, the nominally distinct sciences are not subordinated to one another, but coexist in a condition of democratic equality and coöperativeness. We cannot reduce cultural to psychological phenomena any more than we can reduce biology to mechanics or chemistry, because in either case the very facts we desire to have explained are ignored in the more generalized formulation. But for specific purposes, the student of culture can call for aid upon each and all of the other branches of learning. It is a very important cultural problem whether the natives of South America knew the bronze technique, i.e., whether they consciously produced the observed alloy of copper and tin. But how can the ethnologist solve this problem? Only by requisitioning the services of the chemist.

Now very few would deny that services of the kind rendered by chemistry can also be rendered to the study of culture by psychology. Indeed, most people would at once admit that the relationship with psychology is a priori likely to be far more extensive and thorough-going. A few concrete examples will illustrate how this relationship may be conceived.

Among the quaint conceits with which primitive cultures abound is that of attaching to particular numbers a peculiar character of sanctity. “Everything in the universe,” a Crow Indian once told me, “goes by fours.” As a matter of fact, most things in Crow religious life are adjusted to this conception. An important ceremonial act is thrice feigned so as to be actually performed at the fourth attempt; religious processions halt four times; songs are sung in sets of four; in mythic tales it is the fourth trial that carries an heroic feat to a successful issue. Now this cultural fact very largely eludes psychological interpretation. The first thing that strikes us is that this feature is no peculiarity of the Crow, but is rather widely distributed among their immediate neighbors and even remote Indian tribes, though jointly occupying a continuous area. Since outside of this region other numbers figure as mystic, we cannot regard the view of the sacredness of Four as a general trait of human psychology but must assume that the concept was borrowed by most of the tribes now holding it. A wider survey teaches us that corresponding, though not identical, conceptions are very common. Seven figures in parts of Asia,