There is in living matter everywhere something which escapes the most exhaustive investigation, some subtle center of impulse, which lies beyond the domain of correlated energy, and which acts directively, without increasing or diminishing the total of that energy. Also in the transformations of organic forms, there are preparations and propulsions which no known doctrine of the mechanical, natural causes can interpret. We must accept the presence of the same powers, and in a greater degree, in the life and the history of man.[17-1] It may be objected that abstract ideas are far beyond the grasp of the uncultivated intellect. The reply is, consciously to regard them as abstract, may be; but they exist and act for all that. All sane people think and talk according to certain abstract laws of grammar and logic; and they act in similar unconsciousness of the abstractions which impel them. Moreover, the Idea is usually clothed in a concrete Ideal, a personification, which brings it home to the simplest mind. This was long ago pointed out by the observant Machiavelli in his statement that every reform of a government or religion is in the popular mind personified as the effort of one individual. In every nation or _ethnos_ there is a prevailing opinion as to what the highest typical human being should be. This "Ideal of Humanity," as it has been called, is more or less constantly and consciously pursued, and becomes a spur to national action and to a considerable degree an arbiter of national destiny. If the ideal is low and bestial, the course of that nation is downward, self-destroying; if it is lofty and pure, the energies of the people are directed toward the maintenance of those principles which are elevating and preservative. These are not mechanical forces, in any rational sense of the term; but they are forces the potent directive and formative influence of which cannot be denied and must not be underestimated. Just in proportion as such ideas are numerous, clear and true in the national mind, do their power augment and their domain extend; just so much more quickly and firmly do they express themselves, in acts, forms and institutions, and thus enable the nation to enrich, beautify and strengthen its own existence. We have but to glance along the nations of the world and to reflect on the outlines of their histories, to perceive the correctness of the conclusion which Prof. Lazarus, perhaps the most eminent analyst of ethnic character of this generation, reaches in one of his essays: "A people which is not rich in ideas, is never rich; one that is not strong in its thinking powers, is never strong."[18-1] I claim, therefore, that the facts of ethnology and the study of racial psychology justify me in formulating this maxim for the guidance of the historian: _The conscious and deliberate pursuit of ideal aims is the highest causality in human history._