A publication by Professor Margenau is always of interest to persons concerned with philosophy of science. This is especially true, however, of his recently published book, The Nature of Physical Reality; for this book, dealing with basic epistemological problems arising from the development of modern quantum mechanics, is the most comprehensive and most systematic formulation of its author's philosophical position and is at the same time conceived as a “challenge” to “uncritical realism, unadorned operationalism, and radical empiricism”—to points of view, that is, which Professor Margenau regards as “outmoded and in disharmony with the successful phases of contemporary physics” (v).

The candid student of scientific method will recognize that biology is not entirely a physical science, while acknowledging that it owes its present state of development largely or mainly to physical conceptions and methods. It is clear that the constant features of vital organization and activity presuppose the physical constancies as basis. Nevertheless the living organism has proved in many ways refractory to a purely physical analysis. This is not merely because the higher organisms have their psychical side and that psychological method differs from physical method; conceivably a properly unified science might apply equally to the physical and the psychical sides of nature. Nor is it entirely because vital behaviour is more individualized and less predictable than physical behaviour. It is rather that certain fundamental features of natural process, largely neglected by physics, are just those which are of chief importance in those flux-like entities which are living organisms. The traditional methods of physics, which analyze nature into combinations of invariant elements and processes, are ill-adapted to deal with the fluid, asymmetrical and largely indeterminate features of process as displayed so conspicuously in living organisms. This, put briefly, is the contention of L. L. Whyte, physicist and author of the recent remarkable book on the relations between physics and biology. In the present paper I propose first to consider especially those sections of the book which bear more particularly on the fundamental problems of biology; this part is paraphrase and commentary rather than summary, although never departing far from the subject of unitary principle as defined by Whyte. Later I shall consider some philosophical implications which seem important. For the details of Whyte's exposition the reader should refer to his book, which is notably clear, concise and critical in style and treatment, as well as comprehensive and fully realistic in its point of view.

Certain suggestions recently made by Brunswik (2) concerning the design of experiments in psychology seem to have far reaching implications. Indeed, Brunswik's suggestions appear to the writer to be congruent with Einstein's General Theory of Relativity. Congruences between such diverse disciplines as psychology and physics bear watching if for no other reason than the fact that psychologists frequently point to the physicist as the ideal scientist. Unfortunately, in the writer's opinion, the ideal which the psychologist still admires is the classical, or Newtonian, physicist rather than the modern, or Einsteinian, physicist—the psychologist's outlook being concomitantly distorted. Brunswik's theories of experimental design in psychology, however, are appealing for the very reason that they do not fit the mold of the classical physical experiment, but do seem to be congruent with Einstein's physical theories—with concomitant expansion of scope.

The editor of this Journal has asked me to comment on the preceding paper by Professor Hammond (5) in which certain parallels are drawn between relativity physics and my own suggestions concerning the establishment of “representative design” in psychological experimentation (1). Since I find little basis for criticism of Dr. Hammond's major line of reasoning, I shall concentrate on anticipating possible objections to Hammond's comparison as well as on elucidating my point of view by means of examples, both old and new, that seem pertinent in the present context.

It may be that the overworn analogy between the history of philosophy and a river system has still a value, and if so, it is a value beyond that usually claimed for it. The grosser likenesses between the stream of history and the stream of geography have been, it is true, too often pointed out, while the subtler similarities are neglected. For instance, there are points in both kinds of stream where it runs deep, others where it is shallow; at one point it may run swiftly, as through a gorge, and at another the valley may be wide and the stream broad, and sluggish. However, whereas in the stream of science the running waters often purify themselves, in that of philosophy there are many stagnant pools where the current of criticism has never set in. Further, there are discernible here and there canalizations by which arid plains are artificially irrigated. And it must be admitted that, at other points, outhouses have been built over the stream and its waters sullied.

Philosophers investigating the nature of knowledge from Bacon and Descartes to logical empiricism, have sought to understand its character by means of the distinction between the content of knowledge, and the abstract logical and mathematical principles which regulate its structure or form. The nature of the distinction, the relative roles of content and form, and the relationships between the two, however, have been given widely divergent interpretations.

Men think in terms of models. Their sense organs abstract the events which touch them; their memories store traces of these events as coded symbols; and they may recall them according to patterns which they learned earlier, or recombine them in patterns that are new. In all this, we may think of our thought as consisting of symbols which are put in relations or sequences according to operating rules. Both symbols and operating rules are acquired, in part directly from interaction with the outside world, and in part from elaboration of this material through internal recombination. Together, a set of symbols and a set of rules may constitute what we may call a calculus, a logic, a game or a model. Whatever we call it, it will have some structure, i.e., some pattern of distribution of relative discontinuities, and some “laws” of operation.

The theory of knowledge is justified only by its results. Each of its statements is essentially an hypothesis, valuable in so far as its practical purpose is fulfilled. Consequently, the same speculative characteristics common to all natural sciences, must be attributed also to the theory of knowledge.

Science is based upon the supposition that planning is essential to and effective in the discovery of truth,—planning within and between the minds of individuals. If planning is so, then the cooperative planning of scientific research in the field of the science of religion would contribute to the discovery of truth. The symposia which the Philosophy of Science Association has authorized be published in its journal and the papers on E. S. P. and upon psychoanalytical theory which it secured for its recent national meeting reveal, it seems to the present writer, that the Association recognizes the value of cooperative planning in the discovery of truth, specifically in the field of the science of religion.