science” and “natural science.” For example, the University of Cambridge has inherited the term “moral science” for its department of philosophic studies. The notion is that philosophy is concerned with topics of the mind, and that natural science takes care of topics concerning matter. The whole conception of philosophy as concerned with the discipline of the speculative Reason, to which nothing is alien, has vanished. Newton himself was one of the early scientists who most emphatically repudiated the intrusion of metaphysics into science. There is plenty of evidence that, like many another man of genius, his nerves were delicately balanced. For such men the intrusion of alien considerations into the narrow way of a secure technology produces mere bewildered irritation, by reason of its disturbance of the sense of supreme mastery within the methods of their technique. Of course it would be foolish to believe that any man should dissipate his energies by straying beyond his awn best lines of activity. But the pursuit of knowledge is a cooperative enterprise, and the repudiation of the relevance of diverse modes of approach to the same topic requires more justification than appeal to the limitations of individual activities.
The pathetic desire of mankind to find themselves starting from an intellectual basis which is clear, distinct, and certain, is illustrated by Newton’s boast, hypotheses non fingo, at the same time when he enunciated his law of universal gravitation. This law states that every particle of matter attracts
