An adequate account of the origin and continuance of this isolation of the conduct of intelligence from other conduct is too long a story to be told here. Suffice it to recall that in the society in which the distinction between immediate and reflective experience, between opinion and science, between percepts and universals was first made, intelligence was largely the possession of a special and privileged class removed in great measure from hand-to-hand contact with nature and with much of society. Because it did not fully participate in the operations of nature and society intelligence could not become fully domesticated, i.e., fully naturalized and socialized in its world. It was a charmed spectator of the cosmic and social drama. Doubtless when Greek intelligence discovered the distinction between immediate and reflective experience--possibly the most momentous discovery in history--"the world," as Kant says of the speculations of Thales, "must suddenly have appeared in a new light." But not recognizing the full significance of this discovery, ideas, universals, became but a wondrous spectacle for the eye of reason. They brought, to be sure, blessed relief from the bewildering and baffling flux of perception. But it was the relief of sanctuary, not of victory. That the brilliant speculations of Greek intelligence were barren because there was no technique for testing and applying them in detail is an old story. But it is merely a restatement, not a solution, of the pertinent question. This is: why did not Greek intelligence develop such a technique? The answer lies in the fact that the technique of intelligence is to be found precisely in the details of the operations of nature and of human conduct from which an aristocratic intelligence is always in large measure shut off. Intelligence cannot operate fruitfully in a vacuum. It must be incarnate. It must, as Hegel said, have "hands and feet." When we turn to the history of modern science the one thing that stands out is that it was not until the point was reached where intelligence was ready (continuing the Hegelian figure) to thrust its hands into the vitals of nature and society that it began to acquire a real control over its operations.