It is essentially a truism that the natural sciences have little or no place for dogmatism; to the contrary, there is an underlying skepticism pervading all scientific propositions. Any philosophy which pretends to provide an adequate philosophy of science, should, it seems to me, exhibit epistemologically a corresponding skepticism. At the very least, such a philosophy should demonstrate a skepticism in its views of the “truth” of scientific statements.

Often scholars who call themselves social scientists have not meant by the term science the sort of activity which has generally concerned those calling themselves natural scientists. In the latter sense very little of what has been called “social science” can also be called scientific. The term “social science” as used here refers primarily to the studies which have gone under such titles as Politics (or Government, or Political Science), Sociology, Anthropology, Social and Clinical Psychology, and Economics. To some degree much of what will here be said does not apply with equal justice to the field of Economics. It has a more highly developed system of general abstractions and considerably more precise techniques of analysis than have generally characterized the other social sciences. The difference, however, is one of degree not kind. Many of the difficulties mentioned below certainly plague the field of Economics as well as the others.

Philosophy of science and, more specifically, philosophy of quantum physics can be but special fields of a general philosophy of knowledge; and the problems arising in these fields can be evaluated properly only when they are seen under the perspective of the whole range of human knowledge. This paper deals with problems of quantum physics and, in particular, with the problem of scientific objects in quantum physics from the epistemological point of view previously defined in the author's books, A Philosophy of Science (1940) and The Basis and Structure of Knowledge (1948). The argument of the paper, however, has not been stated before in the direct and concise manner here attempted and may therefore contain elements of novelty even for those readers who are familiar with the books just mentioned.

In part one of this paper we shall elucidate an operational concept of logical simplicity as it seems to function in natural science. Although this is a tentative and exploratory formulation, its novelty, relative to the great European philosophical tradition, seems to require a preliminary warning about misunderstandings.

In Part Two we shall apply the formulation to social inquiry and make a positive suggestion for further development of the proposal.

Professor Margenau's paper presents an analysis of physical theory which has the great merit of exhibiting classical physics and modern quantum mechanics as different aspects of the same epistemological and methodological framework.

By maintaining that “there is not a tree and my construct of it, nor a wave length and my construct of it” he is denying that the constructs of ordinary common sense and, a fortiori, the theoretical constructs of the physical sciences denote entities existing independently of our rational manipulation of them. This denial then enables him to treat constructs like “tree” and “electric current” exactly on a par with the Ψ-functions of quantum mechanics not only methodologically but also ontologically. Once this is granted, he has prepared the ground for his synthesis of classical physics with quantum mechanics and is justified in inferring that “In quantum mechanics, then, the basic mode of description has remained unaltered while the rules of correspondence have undergone radical changes.”

Present-day logic regards definitions as syntactical devices of abbreviation. This view, summed up in the terse adage: “To define is to eliminate,” obscures the vital part played by definitions in deductive sciences. Abstract calculi, to become noetic tools, must be interpreted; so the richer the interpretation, the more efficient the tool. But most calculi are based on a restricted number of primitives; they thus embrace, at the outset, a restricted number of concepts and can be appraised through and only through the definitions they eventually yield. In a word, the richness of a calculus lies in its defining virtualities. The whole of PRINCIPIA MATHEMATICA would be a futile game of chess, did it not embody all our mathematical concepts; none of these being assumed as primitive, PRINCIPIA MATHEMATICA owes its momentous significance to its definitions and to its definitions only.

Here we will discuss the necessary relationship between both prediction and human behavior and meaning and human behavior. The main assumption upon which our thesis rests is that knowing is for the sake of acting and that, consequently, the symbolic process is continuous with overt bodily behavior and with the environment of the knower. A corollary to this assumption is: the locus of meaning is in behavior. Possibly after reading the article it will be clear that meanings presuppose conduct of which we can take cognizance, and that there is a difference between behaving and taking cognizance of behavior (both actual and possible). And although the locus of meaning is in behavior, meanings emerge only in relation to the symbolic process. In a sense we suffer, endure, live through behavior, but in the bare suffering of it there may be no meaning, for meaning requires also the symbolic process.

A major problem of the philosophy of science is the construction of a comprehensive science of man and the universe. The sociology of science has a part to play in this tremendous task by indicating the extra-scientific influences bearing upon science at any given period, assisting, in this way, in developing a self-consciousness of science. It is believed that this self-consciousness is necessary to a scientific appraisal of the method of scientific inquiry, as well as being necessary to any attempt to direct the development of science as an institution. This paper is to be regarded as a sociological evaluation of a work in the field of the philosophy of science, namely, F. S. C. Northrop's The Meeting of East and West.

The death of Alfred North Whitehead late in 1947 was a double loss. Those who knew Whitehead, even slightly, feel keenly the loss of a warm and stimulating personality, which in the last years of his retirement had mellowed to a benign radiance. The wider circle of students and teachers of philosophy who knew him through his writing alone regret the passing of the man who, many thought, was the most capable cosmologist of our time.

“The age-long endeavour to find an intellectual basis for ethics is an enterprise of such importance, and of such difficulty, that any explorer of that country must always be glad to hear the voices of his fellow-travellers. ‘This,’ Wittgenstein once said to me, ‘is a terrible business—just terrible! You can at best stammer when you talk of it.’”

With these words Waddington introduces his symposium Science and Ethics, a “communal, perhaps even co-operative stammering,” as he calls it. Also the present contribution to the “terrible business” cannot be more than a stammering; The business is so terrible today not only because of its inherent difficulties, but because of the tremendous odds which are at stake. When the Renaissance philosophers built the science of material nature they were fired by an enthusiasm of cosmic exploration. Today we are frozen in awe of a cosmic explosion. When Galileo pioneered his new science he knew that he was in the possession of the truth and that his opponents, steeped in error and superstition, would have to give way—eppur si muove! Today, building the science of ethics, we are neither equally sure nor equally confident. Our science is not yet formulated. Our opponents, though not right, may yet conquer before we have had time to develop the new science. We are not sure whether what was true for physics three hundred years ago is true for ethics today.

The intention of the present essay is to urge a reconsideration of the Realism-Phenomenalism-Issue, mainly and primarily in regard to the interpretation of scientific hypotheses; secondarily also relating to the basic problems of epistemology.

In a highly original and provocative essay entitled “Behavior, Purpose and Teleology”, published a few years ago, Professors Arturo Rosenblueth, Norbert Wiener and Julian Bigelow attempt to indicate the scientific importance and usefulness of the concepts of purpose and teleology. Since this essay appeared the suggestions it contains seem to have acquired a significance which was not wholly apparent at that time. This is due primarily to the fact that a somewhat novel and, it appears to some, revolutionary approach to certain problems has arisen in the sciences, an approach which is more or less loosely referred to as “cybernetics,” and among whose outstanding spokesmen are to be found the very authors of this essay—particularly Professor Wiener, whose recently published Cybernetics has been claiming the attention of an increasing number of scientists and non-scientists alike. In his book, it may be noted, Professor Wiener, in tracing the development of cybernetics over the past few years, gives a good indication of the importance he attaches to the earlier essay. He writes, with reference to it: “The three of us [Rosenblueth, Wiener and Bigelow] felt that this new point of view merited a paper, which we wrote up and published. Dr. Rosenblueth and I foresaw that the paper could only be a statement of program for a large body of experimental work, and we decided that if we could ever bring our plan for an interscientific institute to fruition, this topic would furnish an almost ideal center for our activity” (p. 15). It would seem, then, that an examination of the contents of this essay should not be without interest at this time.

In a recent essay (1) Professor Taylor criticizes the criteria used by Rosenblueth, Wiener and Bigelow in 1943 (2) to distinguish purposeful from non-purposeful behavior. He also criticizes our definition of behavior, our concept of the vague as opposed to the general, our use of the word correlation, and our statement that a system may reach a final condition. Indeed, there seems to be little, if anything, in our paper to which he does not emphatically object.

He maintains that the notions of purpose and teleology are not only useless for the understanding of mechanical behavior, but wholly incongruous when applied to this behavior. He further affirms that our use of the term purpose “bears no similarity whatever to the meaning which is ordinarily attached to it.” He does not state, however, his own notions of purpose and teleology; and the meaning which he considers to be ordinarily attached to the term purpose. This omission weakens his criticism considerably.

The following paper is a continuation of an attempt (2) to explore the possibility of intensifying sociological analysis through the development of heuristic devices. The value of heuristic devices lies, so it seems to me, in their essential simplicity and the consequent broadness of their applicability. A heuristic device differs from a law in that it is not an if, then type of proposition. It is a guide to analysis rather than a statement of the necessary issue of the analysis. It suggests how the analysis may be carried forward rather than states how it must come out. The principle of limits as presented below is an attempt to show how this relatively simple heuristic device may be used in a variety of areas of social analysis.

Comments on Professor Feigl's very comprehensive review of the problem of existential hypotheses may take one of two forms. One may accept the problem in Feigl's own terms and either sympathize or criticize the realistic empiricism to which he subscribes. Or, one may feel that the entire approach is ill-founded, and hence that the distinctions in viewpoints which he draws are comparable to splits in a political party whose basic tenets are incompatible with one's own. This comment takes the second course, and as a commentary can do little more than point out the more serious of the differences which separate Feigl's views from those of the writer.

History of Science is a many-sided subject, permitting approach from the point of view of various human interests, and presenting a wide variety of problems, many of them paradoxical and perhaps not capable of satisfactory solution. In the following it will probably seem to the reader a number of times that I am talking at cross purposes. Anything that I can say is of necessity limited by my background as a physicist.

1. Terminological Considerations. Since Russell enunciated the principle, “Wherever possible logical constructions are to be substituted for inferred entities,” or “Wherever possible, substitute constructions out of known entities for inferences to unknown entities,” the terminological situation has become confused. Russell defined neither “construction” nor “inferred entity.” “Construct” soon came to be used for “construction,” perhaps to avoid the ambiguity whereby the latter term was used to refer to both a process and a result. But many writers now use “construction” or “construct” to refer to what Russell called the “inferred entity.” This seems to be the usage of Margenau, Ramsperger, Benjamin, Bures, and many others. Again, some of the same writers in other places (e.g., Benjamin) remain closer to Russell's usage. And I find it difficult to determine exactly the relation of the usage of some writers to that of Russell because of the differences between their contexts and Russell's. I experience this difficulty in reading, for instance, both Miss Stebbing and Werkmeister. The terminological difficulties have been evaded by some other writers who have formulated new terms to refer to Russell's inferred entities. Thus Northrop speaks of the “theoretic component” and Miller has coined the word, “interphenomena.” The terms reflecting Russell's rule in psychology have become so confused that a set of explicit definitions has recently been proposed.

The issue “realism vs. phenomenalism” or “realism vs. positivism” has been widely discussed during the last fifty years. The issue has even become a political and social one in Lenin's Materialism and Empiriocricism, which is built entirely around this topic. He calls “positivism” bluntly a “reactionary philosophy” because it supposedly denies the reality of the world which is described by science. M. Schlick devoted to this issue the paper “Realism and Positivism” which was published recently (in English) with an introduction by D. Rynin. It should, therefore, be welcomed, that Professor Feigl attacked this problem by the methods of modern semantics. This is an attempt to solve a question by precise logical argument which has been frequently treated in a way that provided more heat than light. It is certainly very desirable to scrutinize Feigl's argument carefully and to find out exactly its contribution to our conception of scientific method.

In their penetrating and admirably lucid discussion, “Purposeful and Non-purposeful Behavior,” Professors Rosenblueth and Wiener have considerably clarified the point of view expressed in their earlier paper dealing with the conception of purpose, and recently criticized by me. But while their discussion thus removes some of the difficulties which, I think, stood in the way of acceptance of their position, there yet remain fundamental questions which I do not believe have been adequately dealt with.

These authors rebuke me, with justice, for not indicating my own conception of purposiveness, and they add that this omission weakens my criticisms of their view. That the omission detracts from the interest of my paper is doubtless correct, but that it weakens my criticisms of their position is not similarly obvious. I shall, at any rate, attempt to rectify this defect in the present discussion.

Professor Quine in recent articles has raised an old question, an ontological one, concerning the status of universals. It is interesting to note that the same positions recur in symbolic logic that have appeared so often in the past in less exact language. There can be little doubt that the question he raises is crucial; and if the issue is not yet settled, there is at least some hope that it may be clarified. Propositions are required to make propositions clear.