The whole conception of man already endowed with a mind capable of conceiving civilization setting out to create it is fundamentally false. Man did not simply impose upon the world a pattern created by his mind. His mind is itself a system that constantly changes as a result of his endeavor to adapt himself to his surroundings. It would be an error to believe that, to achieve a higher civilization, we have merely to put into effect the ideas now guiding us. If we are to advance, we must leave room for a continuous revision of our present conceptions and ideals which will be necessitated by further experience. We are as little able to conceive what civilization will be, or can be, five hundred or even fifty years hence as our medieval forefathers or even our grandparents were able to foresee our manner of life today.