The prevailing philosophical mood among those physicists today whose interests are mainly in the field of modern atomic theory, is some form of positivism. This is true not only of the leaders in the field of quantum mechanics, as for instance Heisenberg, Jordan, and Dirac, in whose writings on the philosophical aspects of the recent revolutionary advances in physics the positivistic tendency is clearly visible, but also of the rank and file of competent students of the modern quantum theory.

The Unity of Science movement is directed primarily toward the further advancement of science, but a second phase is entered when the assessment of its significance for various aspects of civilization is undertaken. In this second phase would fall investigations of the utility of its resources in relation to educational problems.

It can not be our purpose to give here a complete account of the phenomenological history of mathematical doctrine. It will be enough to refer to the battle of opinions in mathematical theory which was waged within the last eighty-five years, since Riemann's inaugural lecture on Non-Euclidean Geometry. Furthermore, the revolution which Einstein's theory of general relativity created is indicative of the complete absence of any general awareness that mathematics as a science has any relation to social reality. If we are going to establish such relations, we are conscious of the fact that they would be hotly contended by many mathematicians.

What is the relationship of history to the phylogenetic evolution of man? Historians, like all specialists, are wont to restrict themselves to their own problems and, therefore, do not deal with this question. Only some popular books on the history of the world cross the dividing line between social and natural science. They start with the origin of the solar system, describe the development of the crust of the earth and of life, turn to prehistoric civilization and ancient Egypt, and eventually finish with the history of present times. It is striking that those expositions become more and more detailed the nearer they come to their end. Near the beginning one page describes ten million years, near the end ten months.