Yet here, before discussing further the relation of dualism to science, it is well to observe that the positive history of science justifies the account of its rise which has now been given. The age of science among the Greeks was coincident with the closing conflict between Greek civilization and the general life [p.065] of the Mediterranean, and the age of modern science began, not to attempt a long story, with the discovery of America. All "looking before leaping" is transitional or revolutionary, and while, of course, there had been transitions and degrees of scientific inquiry before, the science of the Greeks belongs to that very critical transition from Greece to Rome; and modern science, to the transition, certainly not less critical, from Christendom to--who can say to what? But not only does history show science to arise when there is a stream to cross; also it shows the life of the time, in the first place, to be sharply disintegrated, its different factors being separately and abstractly expressed through as many different social groups, and, in the second place, in each of the groups to be given to double living, to the storm and stress of being one thing and seeming another. Always an age, conspicuously and characteristically scientific, has been an age of clearly developed classes and of a general duplicity in living. Thus, to give a striking, although possibly too philosophical an illustration of the duplicity, Democritus, the great materialist and atomist, and Plato, the great idealist, were contemporaries and equally were creatures of their day and generation, and their century was the century of great achievements in Greek science. Moreover, as regards the coincident organization of society, we know at least of Plato that he was keenly conscious of the divisions of society into distinct classes. And in very much the same way materialism and idealism, not to mention hedonism and rigorism, or naturalism and supernaturalism, [p.066] have been inseparately associated with the rise and the successes of modern science. These philosophies, it must be remembered, are always more than so many conflicting "isms." They are, too, more than the special conceits, in theory or in practice, of so many separate social classes or of the great leaders of these classes. In their very differences they are the definite, the "public" expression of a conflict, or division, that inwardly affects every individual member, whatever his class or profession, which the society contains. In the day and generation of Democritus and Plato were there not well-defined parties, manifest in all the different and separately organized phases of life--moral, industrial, political or religious, namely, the parties of the conservatives and the radicals? And were there not also, as typical individual characters, each of them revealing to everybody something present within his own life, the only conventional loyalist and the more