Metaphysical problems may be solved by the methods of inference employed in the empirical sciences. So we are told by many realists and pragmatists, among whom may be mentioned Professors J. B. Pratt, William Savery, and Donald Williams. Mr. Williams and Mr. Pratt have argued for the use of inductive methods in establishing the existence of an external world. Mr. Savery has asserted that all philosophical inference as to matter of fact is inductive. This naturalistic attitude is by no means unusual—in fact it is so common in this age in which the speculations of scientists as well as their achievements have captivated the popular imagination, that even philosophers have for the most part failed to examine its validity and presuppositions. It is the purpose of this paper to present such an examination, not of the philosophic employment of inductive methods in general, but in regard to one specific problem; namely, that of the existence of an external world. What I purpose then is to present and evaluate the view that the existence of an external world may be established by inductive methods as employed in the empirical sciences.

In what follows I shall consider symbols only in their function as conveyors of meanings. That symbols have emotive and volitional properties as well, that they have elaborate and complicated relations to the self which uses them, that they are themselves physical counters, i.e., noises, visual objects, etc.,—all of these facts I recognize but choose to neglect. When symbols are considered merely as instruments for the transfer of meanings, only one important assumption is involved, viz., symbols which are precisely defined are to be preferred to symbols which either are undefined or are defined inadequately. In other words, the task of a theory of meaning is that of showing how symbols take on a maximum degree of precision in significance.

In a recent issue of Philosophy of Science Merrit H. Moore contends that it is not only possible but methodologically desirable to separate design in nature from purpose. The main part of his argument is devoted to a support of the proposition that “design” is objective, by which he means that design in the physical world is independent of mind. That which gives interest to Mr. Moore's argument is essentially the Kantian doctrine that the forms of the understanding, and consequently of knowledge, are furnished by the mind and are, in a sense, imposed upon sense-experience thereby making them rational. In contrast to the Kantian view stands the Humean doctrine that knowledge is analyzable into and limited by sense-impressions.

The logician has not been conspicuous for his contributions to scientific knowledge, nor has the scientist been noted for his knowledge of logic. One might readily infer from these observations that there is no necessary connection between science and logic, but I think he would be in error. As one who makes no claim to being either a scientist or a logician, I am perhaps well qualified to say something significant about the logic of science!

The distinction between psychology, logic, and epistemology is a commonplace. The first treats of experience as an act, experience in its relation to the individual observer. The second concerns itself with the internal marks by which truth may be distinguished from error, and in so far as it deals with experience, has to do with some sort of validity of the experience as evidence of a truth. The third discusses in a general way all the elements—observer, object, immediate presentation—which enter into the experience.

So much has been written recently about the marvelous developments in mathematical physics, that we have almost forgotten that the amazing progress of science in the twentieth century was made possible as much by the skill and machinery of the instrument maker as by the genius of the theoretical physicist. The two greatest achievements of modern physics, the relativity theory and the quantum theory, are magnificient examples of the power of experimental instruments to disclose new possibilities and new realms of theoretical study.

As a concrete extension of analyses of scientific method and social study already undertaken in the pages of this journal and elsewhere, the present article will endeavor to clarify certain long-standing preconceptions in classical and neo-classical economic doctrine which still persist and which, in the light of 20th century methodology, can be given no other label than that of pseudo-scientific. These preconceptions revolve primarily about the ideas of “value,” “cost,” “utility,” and “price,” which ideas have suffered little change to the present day and which even early writers recognized as being vague and ambiguous.

We now proceed to define certain terms which we shall apply to sets of axioms and derive a few properties. A great deal of what follows in this section is still based on a two-valued logic, while our criticism of the usual independence and consistency proofs is based on an n-valued logic. The necessary alterations are now being worked out by the author.