The note thus touched upon is important. The larger fields of application of modern psychology are those of political, industrial, national, and international concern. There is a psychological approach to almost every public question. To embark upon such an experiment as nationwide prohibition without the benefit of expert psychological examination is but a flagrant instance of the unwisdom invited by democracy tempted to the ways of demagogy. The fact that the alcoholic temptation lies so close to the crime issue, that it represents a psycho-neural craving as old as mankind and as widespread, that it holds a close relation to the masculine psychology of escape and search for intensive thrills - all this should have indicated the province, along with the allied specialties of physiology and psychiatry, in which the policy of wisdom in regulation was to be sought. But political eyes are blind, and political ears are deaf to the appeal of calm scientific investigation, when issues must be reduced to votes and the ordinary limited comprehension and prejudices of voters.

Yet prohibition is a small concern, despite its wealth of lessons in wrong ways of righting ills, as compared with the stupendous dimensions of war, which is likewise a psycho-political issue. To recognize that man has ever been his own worst enemy, that the most intelligent of species is the only one that engages in collective extermination on a race-suicidal scale, is as far as the reference can here be carried. It is germane for its inclusion of the mass psychology in which social psychology finds its culminating problem and expression. Human gregariousness is a formidable quality; it makes the cosmopolitan centers, crowding humanity into congested quarters, conferring the benefits of cooperative enterprise, and creating the larger loyalties that make patriotism possible and national ideals realizable. Yet it sets nation against nation and multiplies to colossal proportions the menace of conflicts inherent in the contentious motives of the industrial members of the human herd. Collective psychology is itself a specialty, considering the contagion of example, the spread of prejudice, the vogue of fad and fashion, the lowered mentality under crowd pressure, the insanity of the frenzied mob. To reconcile the social with the industrial nature, to direct social pressure wisely and form public opinion judiciously, is the problem of civilization. The Freudian recognition of the conflict is in the name of the censor, which may be a Puritan conscience or a worldly Mrs. Grundy, a Calvinistic restraint, or an aristocratic oppression. Through it all we recognize that man cannot follow his original nature and become a useful citizen or a civilized being. Man is the only animal who reconstructs his own nature, and in that process finds the glorious opportunities of realizing his potentialities. Civilization is psychological reconstruction.

Psychology makes no pretense to be all things to all men. It aims to be a naturalistic science among the sciences, but deals with the psychic realm which is alike the instrument of human understanding however directed, and also the subject matter, when the mind explores its own nature. The renaissance of psychology is a story of rapid expansion within hardly more than a single generation. It seems worth the effort to include in a single canvas, however crowded, the movements of ideas and inquiry contributing to its recent advance, and to do so from the unifying point of view of a naturalistic psycho-biology.

Psychology, in coming in line with the natural sciences, plays its part in the rationalization of knowledge, and an important one. Many of its fundamental problems are ancient; but the solutions shift with the temper of the times, with the advancement of learning. There is an evolutionary psychology in sequence of development. The spiritistic and the moralistic trends dominate in primitive psychology. Man formulated his"soul" in those terms. His purpose was to appease the gods and control his own fate. His psychology was shaped in the image of his desires.

As learning became established, the doctrines became academic and solutions traditional. Authority and consensus established what was held to be the truth and ever in fair conformity to religious, moral, or social codes supported by established authority. Because of the lack of knowledge of nature's ways, a pretentious and assertive pseudo-science flourished, mingling with folklore beliefs. Parallel to the progression from alchemy to chemistry, from astrology to astronomy, is a similar growth from a primitive, a religious, and an academic psychology to a body of doctrine that is conceived in the spirit of natural science and proved by way of experiment.

The conclusion to be drawn from the renaissance and its antecedents is that issues once regarded as lying outside the realm of the methods of science may be pursued in the same temper and logic as have brought about the great advances in the physical sciences and the control of natural resources. This does not mean that psychology will be reducible to physics or physiology; its distinctive province remains and will ever require adaptation of technique to the conditions under which the phenomena occur. But it has become possible to focus psychological findings upon the conduct of human affairs, to recognize the voice of psychology in many concerns formerly decided by the guidance of religious precept or legal enactment, and above all to naturalize psychology in the federation of the sciences. Upon the wise application of the principles thus emerging depends in no small measure the direction of future progress.