The association of determinism with the coming of experimental science in the modern world was an unnecessary carry-over of certain aspects of the medieval belief that the aim of knowledge is to grasp or contemplate “eternal truth.” If we take a science such as chemistry or physics as typical instead of astronomy, it would seem that control of actual concrete transformations is the acid experimental test rather than prediction of “inevitable” future events. The latter surely has the smell of pre-scientific prophecy. If so, and if we choose to base our interpretation of science and our philosophy of nature on this consideration, we can avoid determinism without in any way limiting the efficacy or potential universality of science. At the same time we avoid the traditional metaphysical or theological notion of “free will.”

With the advent of the relativity theory science has entered a transformative period in which previous certainties are undergoing critical scrutiny and renovation. Critical movements in science arise at periods of its history when its foundations are brought into question. True it is that natural philosophers still regard science as a growing body of propositions dealing with natural events enabling them to find the structural laws of the external world. But this “external world” about them changes in significance, interpretation, and meaning as new epoch-making theories are propounded and experimental verification of some of their consequences tend to give them scientific plausibility.

It is too often forgotten that even the most “objective” science such as physics is but a description, interpretation and ordering of physical reality from a selected point of view.

In founding terrestial dynamics, Galileo, the father of modern experimental physics, selected concepts that could be given exact mathematical definitions and cast in a form conducive to quantitative results. The qualitative aspects of observed phenomena, such as the color of an accelerated body, and the ultimate cause of motion—a purely metaphysical problem—do not enter into the mathematical dynamical system of Galileo.

This paper is concerned with a question in metaphysics. The question is: Is the world ultimately one, or is it many? It is neither a very profound nor a very complicated question. It is, on the contrary, very simple. But despite its simplicity, it expresses the most basic of all metaphysical problems.

When two metaphysical problems, A and B, are so related that the statement of B assumes an answer to A, then we may fairly infer that A is more basic than B, and B less basic than A.

“He's [the Red King's] dreaming now,” said Tweedledee: “and what do you think he's dreaming about?”

Alice said, “Nobody can guess that.”

“Why, about you!” Tweedledee exclaimed, clapping his hands triumphantly. “And if he left off dreaming about you, where do you suppose you'd be?”

“Where I am now, of course,” said Alice.

“Not you!” Tweedledee retorted contemptuously. “You'd be nowhere. Why, you're only a sort of thing in his dream!”

“If that there King was to wake,” added Tweedledum, “you'd go out—bang!—just like a candle.”

“I shouldn't!” Alice exclaimed indignantly. “Besides, if I'm only a sort of thing in his dream, what are you, I should like to know?”

“Ditto,” said Tweedledum.

“Ditto, ditto!” cried Tweedledee.

He shouted this so loud that Alice couldn't help saying “Hush! You'll be waking him, I'm afraid, if you make so much noise.”

“Well, it's no use your talking about waking him,” said Tweedledum, “when you're only one of the things in his dream. You know very well you're not real.”

“I am real!” said Alice, and began to cry.

“You won't make yourself a bit realler by crying,” Tweedledee remarked: “there's nothing to cry about.”

“If I wasn't real,” Alice said—half laughing through her tears, it all seemed so ridiculous —“I shouldn't be able to cry.”

“I hope you don't suppose those are real tears?” Tweedledum interrupted in a tone of great contempt.

—Through the Looking Glass

The attempt to draw a clear distinction between Philosophy and the empirical sciences can almost be taken as the defining trait of the analytic movement in contemporary philosophical thought. The empirical science that has most frequently threatened to swallow up questions of particular interest to philosophers since the time of Descartes has been psychology. Characteristic, then, of analytic philosophy has been the rejection of what it terms psychologism, that is to say, the mistake of identifying philosophical categories with those of psychology, whether introspective or behavioristic. It is clear that to launch an attack on psychologism, thus conceived, presupposes that one has a list of philosophical categories which one is able to identify as such; and this in turn presupposes an ability to sketch, at least in a general way, a distinctly philosophical account of these concepts, although a systematic account along non-psychologistic lines may be a distant and ill-defined goal. The analytic movement in philosophy has gradually moved towards the conclusion that the defining characteristic of philosophical concepts is that they are formal concepts relating to the formation and transformation rules of symbol structures called languages. Philosophy, in other words, tends to be conceived of as the formal theory of languages. From this standpoint, consequently, psychologism is conceived of as the psychological treatment of concepts which are properly understood as formal devices defining a mode of linguistic structure.

Any physical theory which seriously proposes that events in the future may be the efficient causes of events in the past certainly may be regarded—at least at first glance—as a rather revolutionary doctrine. In a recent issue of the Reviews of Modern Physics (Vol. 17, Nos. 2 & 3, p. 157) commemorating Niels Bohr's sixtieth birthday, and under the editorship of the latest Nobel Prize winner in physics, W. Pauli, there appeared such a theory—written by Bohr's former student, J. A. Wheeler and Wheeler's associate (and former student) at Princeton, R. P. Feynman. The title of their paper appears harmless enough: “Interaction with the Absorber as the Mechanism of Radiation.” It is one part of a more comprehensive three-part paper intended for later publication as a general constructive critique of classical field theory (Maxwell's electrodynamics) and of the theory of action at a distance as propounded by Schwarzschild and Fokker. (In passing, we note that in this more general paper there is derived the Frenkel solution of the old problem of infinite self-energy of the point-charge electron.)

Although generalization is universally relied on in all scientific thought and is prerequisite to it, many students of scientific methods have neglected to analyze generalizing behavior. This is understandable in view of the fact that generalizing thought begins early in childhood and continues at simple or complex levels through the years of elementary school, high school and college. Most such generalization is clearly pre-critical, following the patterns of parents, playmates and teachers by means of suggestion, imitation and insight. In spite of its universality, however, the process of generalization deserves careful analysis in order that it be fully understood and that errors in interpretation of experience due to faulty generalizing may be avoided.

The boundaries of psychology have never been very distinctly defined and, as a consequence, science has witnessed frequent border incidents. But it obviously is not psychology alone which suffers from such lack of delineation, but its neighbors, the biological and social sciences, do as well. Cooperation between sciences becomes difficult under these conditions. All agree that psychology is the science of mind, but few agree to what “mind” is. At least within our century “mind” has been taken to be “behavior”, for the present day outlook is that mind is behavior rather than that which is responsible for behavior (3). The metaphysical dynamism of a prime mover has been replaced by an experimental concept, i.e., one that is susceptible to scientific investigation. There is no need to review the complex history of behavioristic psychology in its many ramifications, ranging from Watson's mechanism to the various vitalistic teleologies. We turn instead to a fundamental problem on which there is little agreement: “What kind of behavior should be called mind?”

Although a great deal has been written concerning the verifiability of empirical, declarative sentences, yet some further clarification in this area seems possible and desirable. I think it is important to determine what sort of property ‘verified by’ is. Obviously it is a semiotical property. Only sentences, never matters of fact, are verified. But where, in the area of semiotics, is it to be placed? To use Charles Morris's useful and now somewhat traditional classification, is it a syntactic, semantic, or pragmatic (i.e. psychological) predicate? My answer is that it falls within semantics. Before developing this, however, I should like to point out why I do not place it in either of the other two subdivisions.

At the beginning of the twentieth century, philosophy in America and England began to respond to the rumors of unrest and dissatisfaction which were under way at the close of the nineteenth century. Many contemporary thinkers, who have had occasion to look backward, have remarked on the dominance of idealism at the turn of the period. Montague says it was “rampant” and points to the organization of the St. Louis school by W. T. Harris, the purpose being a study of Hegelian thought. Lovejoy also remembers the total sweep of idealistic thought. “The metaphysics of the philosophical teachers whose influence was dominant in most of the American universities thirty-five years ago had one common and fundamental premise which was supposed to be established beyond the possibility of reasonable doubt; to question it was simply to betray one's want of a genuine initiation into philosophy. It was the proposition that, in Bradley's words, 'to be real, or even barely to exist, is to fall within sentience; sentient experience, in short, is reality, and what is not this is not real. There is no being or fact outside of that which is commonly called psychical existence.' As my first teacher in philosophy, George Holmes Howison, said, in summing up a memorable philosophical symposium in 1895: 'We are all agreed' in one 'great tenet;' which is 'the entire foundation of philosophy itself: the explanation of the world which maintains that the only thing absolutely real is mind; that all material and all temporal existences take their being from Consciousness that thinks and experiences; that out of consciousness they all issue, to the consciousness they are presented, and that presence to consciousness constitutes their entire reality.' With almost a whole generation of acute and powerful minds this passed for a virtual axiom.”

My beliefs during the first stage of my philosophical career were a mixed brew of ingredients taken from the Greek and Christian traditions. My tastes were conservative and even reactionary. I believed in the reality of substance, material and mental; I held that there are universal and necessary connections in nature which can be known. In short, I was a naive objectivist about things and about structures. I was a realist about values too. I believed that there are such traits in nature as good and bad, right and wrong, beauty and ugliness, independently of my preferences. I was convinced further that goodness was a supreme causal agent; that—to paraphrase the familiar quotation—righteousness is power. I believed in God. With Plato (in the Phaedo) I maintained that causality is not only efficient but final too; that nature exhibits both a mechanical and a moral order. And these two propositions were, to my view, but twin aspects of the one proposition that nature will not deceive my expectations.

W. E. Hocking has written recently that Whitehead's descriptive generalization of concrete fact, namely, his actual occasion, is “… not a term of description in the direct sense. It is an hypothesis. It cannot be kept in place by pointing to its presence as a datum: it can only hold its own if it proves to be a valuable conceptual tool.” I further advance the thesis that all generality is hypothetical, and holds it own only if it proves to be conceptually useful. This is in accord with Whitehead's statement, the full implications of which have not been taken seriously enough, that metaphysical categories are not dogmatic statements of the obvious; they are tentative formulations of the ultimate generalities. But when these tentative formulations prove conceptually useful or are conceptually employed, they lose their “hypothetical air,” and often pass into what Whitehead calls a false state of “sober obviousness:”

“An old established metaphysical system gains a false air of adequate precision from the fact that its words and phrases have passed into current literature. Thus propositions expressed in its language are more easily correlated to our flitting intuitions into metaphysical truth. When we trust these verbal statements and argue as though they adequately analysed meaning, we are led into difficulties which take the shape of negations of what in practice is presupposed. But when they are proposed as first principles they assume an unmerited air of sober obviousness.”

In this article we will explain and defend the proposition: “A statement which prescribes (entails) the conditions for its verification is a scientific statement.” We will confine our consideration to factual (synthetic) statements alone, although it may be true that our proposed proposition refers to formal, analytic statements also.

If prescribing the conditions for its verification is the only necessary qualification for a statement to be scientific then obviously the means of arriving at such a statement is irrelevant. It does not matter whether we have performed many experiments or none before making a scientific statement. There are, of course, reasons for having a systematic method of arriving at the formulation of scientific statements, but this does not make them more, or less, scientific.

The major question—what is categorial analysis and how can it be reliably performed?—lies beyond the scope of this paper. Indeed, I would presume that very little can be said significantly about it in general. One's convictions on the subject have to be shown by actual performance, which is my intention in the present instance. But it may help the process of communication if I try to indicate at the beginning the general frame in which this analysis of value occurs.

Ever since the beginning of the modern era of science, more than 300 years ago, the scipntist has been embarassed at times when he undertook to describe the scope and objectives of science. Part of this embarassment was due to the difficulty of setting up the scope and objectives in such a way as to leave room for future development, and at the same time to permit of seeing the limitations of science clearly and truthfully. Recently in an article “On the possible philosophies of science”, Professor Malisoff made use of the old practise in philosophical discussion of using conjugate terms. These terms as used are so selected that complementary pairs characterize or describe an entity or whole of some kind. The difficulty in describing the scope, objectives and especially the limitations of science, arises chiefly from the difficulty of establishing some simple entity that will contain all of this as well, as the remainders that must be included, and that involve the limitations of science, chiefly. This use of conjugate terms offered a solution of this difficulty.

It is the proudest boast of the sciences that they are objective, clean of moral judgments, wertfrei. This insistence was salutary as the physical sciences struggled to loose themselves from the bonds of tradition, and it was natural that the social sciences took over the emphasis. Yet by a quirk of history the latter disciplines in striving for objectivity and amorality are unscientific. Far from being the hallmark of scientific method that students of society think it, the doctrine of Wertfreiheit is of religious origin. It has always been the spokesmen of tradition who have said that science is without reference to morals and value, relegating this province to themselves.

It is a happy circumstance that this important aspect of method should be brought to our attention by a distinguished scientist in the field of biology. In the past any reference to the “psychical” by the scientific methodologist has been regarded as a dubious departure from his strict routine. But the recognition, finally, by a man of science, of the aleatory, autonomous character of a spontaneous universe, disclosed in biological directives as well as in the dynamics of the atom, is a stimulating enhancement of that philosophy which, as Dewey says, is “the critical theory of methods of criticism.”

The following remarks have been stimulated by Mr. A. J. Ayer's recent essay “The Terminology of Sense Data.” In this paper Mr. Ayer restates several of the points he has made in his book The Foundations of Empirical Knowledge. The context of his argument is that of the traditional distinction between two kinds of things, sense data, percepts, phenomenal or direct given-nesses on the one hand and so-called physical objects on the other. In this context, Mr. Ayer's argument is, to my mind, very admirable; so I do not intend to comment on it. In some other contexts, some of his formulations may, I fear, give rise to misunderstandings; these, naturally, are the points on which I wish to comment. But before specifying them, I had better make sure that we are talking about the same thing by briefly restating several of Mr. Ayer's points. With some of these, if I understand them correctly, I find myself in agreement; the merit of some others I shall presently examine.