ABSTRACT
We have observed that the heart of the new scientific metaphysics is to be found in the ascription of ultimate reality and causal efficacy to the world of mathematics, which world is identified with the realm of material bodies moving in space and time. Expressed somewhat more fully, three essential points are to be distinguished in the transformation which issued in the victory of this metaphysical view; there is a change in the prevailing conception (1) of reality, (2) of causality, and (3) of the human mind. First, the real world in which man lives is no longer regarded as a world of substances possessed of as many ultimate qualities as can be experienced in them, but has become a world of atoms (now electrons), equipped with none but mathematical characteristics and moving according to laws fully statable in mathematical form. Second, explanations in terms of forms and final causes of events, both in this world and in the less independent realm of mind, have been definitely set aside in favour of explanations in terms of their simplest elements, the latter related temporally as efficient causes, and being mechanically treatable motions of bodies wherever it is possible so to regard them. In connexion with this aspect of the change, God ceased to be regarded as a Supreme Final Cause, and, where still believed in, became the First Efficient Cause of the world. Man likewise lost the high place over against nature which had been his as a part of the earlier teleological hierarchy, and his mind came to be described as a combination of sensations (now reactions) instead of in terms of the scholastic faculties. Third, the attempt by philosophers of science in the light of these two changes to re-describe the relation of the human mind to nature, expressed itself in the popular form of the Cartesian dualism, with its doctrine of primary and secondary qualities, its location of the mind in a corner of the brain, and its account of the mechanical genesis of sensation and idea.
