What we call “science” today was in its primitive state part and parcel of that common stock of knowledge and belief which makes up a community’s literature, or, as Dr. Beattie Crozier would have said, its “Bible.” The departure of science from this main body of literature begins for the Western World, probably, with the death of Plato and the institution of Aristotle’s collections in natural history; and from that point onwards the separate sciences, increasingly isolate themselves from the general body of knowledge, and utilize methods which had been unknown to the earlier philosophers and sages; so that by the time the twentieth century dawns the process of differentiation has been completed, and philosophy, once the compendium of the sciences, has disappeared except as a sort of impalpable, viscous residue. When Aristotle divided his writing into the exoteric and esoteric groups, into the popular and the scientific, he definitely recognized the existence of two separate branches of literature, two different ways of taking account of the world, two disparate methods of approaching its problems. The first branch was that of the philosophers, the prophets, the poets, and the plain people. Its background was the generality of human experience: its methods were those of discussion and conference: its criteria were those of formal dialectics: its interests were specifically those of the community, and nothing human was foreign to it. With the petrification of Greek thought that followed the collapse of the Alexandrian school, the second branch was slow in coming into its own. As late as the eighteenth century its adherents were called natural philosophers, to distinguish them from the more humane variety; and it is only with the nineteenth century that the subject became universally known as science and its practitioners as scientists. In the Phædrus Socrates had expressed the humanist outlook of literature by saying: “Trees and fields, you know, cannot teach me anything, but men in the city can.” The shortest way of describing the attitude of science is to say that it resolutely turned its back on men in the city and devoted itself to the trees and fields and stars and the rest of brute nature. If it paid attention to men at all it saw them--if we may abuse an old quotation--as trees walking. Socrates had said: Know thyself. The scientist said: Know the world that lies outside man’s dominion. As science progressed these attitudes became more rigid, unfortunately, and a conflict grew up between literature and science, between the humanities and natural philosophy, which has given both art and science the peculiar twist we shall presently examine.