When mathematics and other rational sciences developed among the Greeks, scientific truths did not react back into daily experience. They remained isolated, apart and super-imposed. Medicine was the art in which perhaps the greatest amount of positive knowledge was obtained, but it did not reach the dignity of science. It remained an art. In practical arts, moreover, there was no conscious invention or purposeful improvement. Workers followed patterns that were handed down to them, while departure from established standards and models usually resulted in degenerate productions. Improvements came either from a slow, gradual, and unacknowledged accumulation of changes or else from some sudden inspiration, which at once set a new standard. Being the result of no conscious method, it was fittingly attributed to the gods. In the social arts, such a radical reformer as Plato felt that existing evils were due to the absence of such fixed patterns as controlled the productions of artisans. The ethical purport of philosophy was to furnish them, and when once they were instituted, they were to be consecrated by religion, adorned by art, inculcated by education and enforced by magistrates so that alteration of them would be impossible. It is unnecessary to repeat what has been so often dwelt upon as to the effect of experimental science in enabling man to effect a deliberate control of his environment. But since the impact of this control upon the traditional notion of experience is often overlooked, we must point out that when experience ceased to be empirical and became experimental, something of radical importance occurred. Aforetime man employed the results of his prior experience only to form customs that henceforth had to be blindly followed or blindly broken. Now, old experience is used to suggest aims and methods for developing a new and improved experience. Consequently experience becomes in so far constructively self-regulative. What Shakespeare so pregnantly said of nature, it is "made better by no mean, but nature makes that mean," becomes true of experience. We do not merely have to repeat the past, or wait for accidents to force change upon us. We _use_ our past experiences to construct new and better ones in the future. The very fact of experience thus includes the process by which it directs itself in its own betterment.