The final consideration to which I ask your attention in this discussion of social forces in American life, is with reference to the mode of investigating them and the bearing of these investigations upon the relations and the goal of history. It has become a precedent, fairly well established by the distinguished scholars who have held the office which I am about to lay down, to state a position with reference to the relations of history and its sister-studies, and even to raise the question of the attitude of the historian toward the laws of thermodynamics and to seek to find the key of historical development or of historical degradation. It is not given to all to bend the bow of Ulysses. I shall attempt a lesser task. We may take some lessons from the scientist. He has enriched knowledge especially in recent years by attacking the no-man's lands left unexplored by the too sharp delimitation of spheres of activity. These new conquests have been especially achieved by the combination of old sciences. Physical chemistry, electro-chemistry, geo-physics, astro-physics, and a variety of other scientic unions have led to audacious hypotheses, veritable flashes of vision, which open new regions of activity for a generation of investigators. Moreover they have promoted such investigations by furnishing new instruments of research. Now in some respects there is an analogy between geology and history. The new geologist aims to describe the inorganic earth dynamically in terms of natural law, using chemistry, physics, mathematics, and even botany and zoology so far as they relate to paleontology. But he does not insist that the relative importance of physical or chemical factors shall be determined before he applies the methods and data of these sciences to his problem. Indeed, he has learned that a geological area is too complex a thing to be reduced to a single explanation. He has abandoned the single hypothesis for the multiple hypothesis. He creates a whole family of possible explanations of a given problem and thus avoids the warping influence of partiality for a simple theory. Have we not here an illustration of what is possible and necessary for the historian? Is it not well, before attempting to decide whether history requires an economic interpretation, or a psychological, or any other ultimate interpretation, to recognize that the factors in human society are varied and complex; that the political historian handling his subject in isolation is certain to miss fundamental facts and relations in his treatment of a given age or nation; that the economic historian is exposed to the same danger; and so of all of the other special historians?