The history of Western Thought since the seventeenth Century leaves little doubt as to the practical validity of the method of natural investigation discovered by Galileo, interpreted by Descartes, and variously generalized by Newton and Einstein. The repercussions of its success on every level of human activity, religious, political, commercial, and educational (to mention only the more obvious ones) have awakened the most diverse ánd even contradictory speculations as to the nature of this science and the objectives of the scientist. Often enough one gets the impression that these speculations are founded on an arbitrary and unjustifiable conception of the nature of modern science; a conception formulated in terms of what one thinks or wishes to think science is from its effects upon the extra-scientific domain (which, in this context, includes philosophy) rather than in terms of a patient and critical penetration of its intrinsic structure.