Ever since experimental science, which is a cumulative cultural enterprise, first appeared upon the social scene in western Europe in about the seventeenth century, the philosophers, in order to avoid the sense of defeat and discouragement which its successes gave them, have felt crowded out of the public world and have retreated to a defense of their own sensations. Although themselves guided by a scrupulous adherence to fact and logic, they have been concentrating upon the subjective end of the knowledge relation, on the assumption that nobody would be able to disturb them there. The microcosm of feeling seemed to be a refuge from the macrocosm of the world where measurement and instruments are employed far and wide without limit. And the harder the philosophers become pressed by the progress of nearby sciences, such as neurophysiology, the more they concentrate on the privacy of the subject when he is alone with his feelings.