The scientific world-outlook is something quite different from natural science. The word “science” in its legitimate modern usage represents both a kind of knowledge and the method of obtaining that knowledge. By “science” we may mean an objective body of facts and relationships concerning the physical world and arrived at by the scientific method of observation and reasoning—preferably quantitative observation and mathematical reasoning: thus we may say that the law of constant proportions is a part of the science of chemistry. But we may also use the word science to denote that scientific method which I have just mentioned: thus I may say that science is the key to the investigation of nature—or that some inaccurate or biased piece of work is unscientific. Science, in either of these senses, does not contain any world-outlook, for it is quite impersonal. Thus science in the first sense consists of certain statements and relationships e.g.—that sulphur is yellow, that Jupiter has eight satellites, that all solutions of acids in water conduct electricity; while the scientific method indicates the manner in which from the data of our sense-impressions we can infer statements and conclusions, such as the above, which will be found to represent the phenomena correctly. But a scientific world-outlook means something different, because it is a world-outlook, the attitude of a man or woman towards the whole of that of which he or she is conscious.

By a “world-outlook” I mean a systematic account of the nature of the world which claims, by showing the place of man in the scheme of things, to indicate the point and purpose of his life. The theory of the world is often called a metaphysical theory and the theory of conduct an ethical or moral theory. In my opinion the clarification and criticism of world-outlooks is a fundamental part of philosophy. Indeed, I hardly think that philosophy would have existed as something distinct from science or poetry but for the tendency to attempt some explanation of the world as the scene of human endeavour. When Kant referred to “the inevitable problems of pure reason” about “God, freedom, and immortality,” he was referring in a summary way to the fundamental philosophical task of analysing and criticizing world-outlooks, a task that may be undertaken even by those philosophers who do not believe that any world-outlook is or could be adequate. It is clear, of course, that the civilized religions, since they seek to show how human conduct fits in with some Divine Plan or Cosmic Conflict, have world-outlooks. It is, however, misleading to look upon religions and world-outlooks as the same thing, as some people do. For in ordinary usage religion involves belief in supernatural beings and conduct regulated in the light of this belief, but according to some world-outlooks (e.g. that of Spinoza) there are no supernatural beings, while according to others (e.g. Epicureanism) beings may exist deserving that description but human conduct need take no account of them.

This essay is an attempt to take stock of what has been done by those who have worked on the foundations of mathematics and to suggest, very inadequately in so short a space, what may be a satisfactory approach to this subject for one who is not an expert in it. The subject is one that neither mathematicians nor philosophers can any longer afford to ignore, but in the technicalities of which they may not be very interested.

(1) Property a psychic link. W. James on self and mine. (2) Acquisition and conservation in the light of expectation. (3) Expectation in philosophy and psychology. (4) Baldwin and property. (5) Bentham. (6) Why acquisitions are conserved. (7) Property as the basis of expectation and as witness of foresight. (8) Possessive pronouns. (9) Animals and children. (10) Property viewed objectively by Petrucci and subjectively by Bentham.