It is the purpose of this note to comment on some important problems which have been already vividly discussed by several authors. Besides the well known former discussions of Schrödinger and J. v. Neumann I should like to mention here especially H. Margenau's article, “Critical Points in Modern Physical Theory,” (3) which strongly influenced my present discussion.

A physical theory is a construction of thought which is founded on experience so as to constitute knowledge of the natural world. Propositions in physics are constituted of concepts which express the properties and processes of the physical world. For purposes of record and communication concepts are designated by the terms of a language, such as mathematical symbols, and philosophical discussion may be based on linguistic forms. In this essay, however, the element of discussion will be the concept as a mode of thought through which are grasped the attributes of physical things and the relations exemplified in physical processes. The present philosophical analysis of a physical theory, quantum mechanics, is to be carried out by critical analysis of its basic concepts. In particular, the program is to show that in quantum mechanics the concept of physical object exhibits the characters of discontinuity, complementarity, and relativity.

The philosophy of quantum mechanics has often been conceived by physicists as a collection of dogmas concerning what can be measured, observed and known. To this branch of dialectics the present paper does not attempt to contribute, chiefly because it is written from the conviction that no part of science, nor any philosophy, can safely predict what may be feasible or knowable. Rather, this brief essay endeavors to expose the epistemology of quantum physics in a way which allows it to be recognized as an extension of the ordinary processes of cognition, as the continuation of a line which starts in sensory perception, leads straight through the methods of classical physics into quantum mechanics and shows no signs of terminating even there.

Modern physics, which had its beginnings in the inclined-plane experiments of Galileo, deals with the measurable aspects of the world about us. The laws and definitions of classical physics are, at least superficially, differential equations in which each variable represents the result of a particular kind of measurement. These variables are usually called physical quantites. Starting from a few general laws and definitions we can derive formally further relations between the physical quantities and their rates of change in space and time. If the original definitions are self-consistent and the original laws accurate, the relations we derive from them should enable us to predict what the numerical result of a certain measurement will be whenever certain other measurements have yielded specified numerical results.

In October 1946 the U. S. Government summoned the representatives of Labor and Management to meet in Washington to try and find a basis for cooperation which would make possible increased productivity. For two days two hundred of the outstanding individuals in this field talked and debated. The results were hardly worth the efforts. The most appropriate summary of the “results” of these meetings was provided by Fortune magazine when it characterized the whole affair as a “meaningless squabble.“

There is a notion, cataleptic in its effects, that discussion in ethics and values must ultimately be blocked by the “naturalistic fallacy.” We can go so far in analyzing the categories of “good,” “right,” “ought,” “valuable,” and the like, but never so far as to embark from the field of logic or general philosophy and enter the alien provinces of science—at least with a visa. To think to reduce moral problems to those of psychology or biology or (in Northrop's amendment) to those of “culture,” is The Fallacy, insensitivity to which brands one as a positivist, a dupe of “scientism,” or at least a sympathetic fellow-traveller. Though the vocabulary of The Fallacy is not old—G. E. Moore and his earnest commentators will date it—the idea is almost as antique as philosophy itself; indeed, it is one of the prime devices whereby philosophy has managed to rationalize its subject-matter as something more than an historical accident.