In raising the question of what is a monad I am continuing along the line of two previous discussions. Those dwelt with the questions of what is an atom and what is a gene. Each contained proposals to sharpen meanings of old terms rather than to resort to new ones. The old term “monad” will also be subject to such a proposal. It will not mean merely any one of a dozen things it has meant to different users, but will serve as a more or less well fitting name for the third member of the sequence: atom-gene-x.

Scientific method in philosophy has been so greatly developed and widely accepted in our day that it seems almost ready to lay claim to the self-evidence which an older rationalism professed. It is my belief that it leaves out something essential to philosophy. I shall not attempt to define scientific method in philosophy, since it is a movement with several wings, rather than a definite set of propositions accepted by all its advocates; but its intent is clear. The theme of current criticisms of metaphysics and speculation has been that philosophy has no private access to the truth, no monopoly of such knowledge as human beings possess; it stands on an equal footing with the sciences. The observation is sound and timely; but from it has been drawn, at least by implication, the conclusion that there is no such thing as philosophy at all. For unless it has a peculiar method, or a distinct subject matter, or some other distinguishing trait, philosophy is only a convenient name for a certain group of men and the books they wrote. The criticism was made because philosophy had come to be identified with a set of dogmas. I wish to suggest instead that it is a peculiar kind of inquiry into a distinct subject matter. Philosophy is the attempt to formulate principles or categories which the philosopher already possesses, in common with everyone else, but in an unformulated state. Philosophy is always developing theories and systems, but they are tentative, not final and dogmatic; the categories are certain, but their statement is provisional; therefore, the process of inquiry is unending.

The question of the character, function and possibility of philosophy can best be considered through an analysis of how men come to philosophize. Were the ideals man seeks always satisfactory to him and the consequences of his conduct and allegiances always what he expected, undoubtedly he would not be the philosophical animal he is. It is precisely because his emotional attachments are so often disillusioning and his actions ineffectual, that he is compelled to reflect upon what ends are worthwhile and what conduct and instrumentalities would bring them into being. Such reflection is the practice of philosophy and, where it is systematic and grounded on the evidence available, constitutes the discipline known as philosophy. Its source is living itself, and it is a kind of life. It is a method whereby life seeks the solution of its own problems; for living is made up of man's responses to his world, responses directed to the management of things for better and worse; and what would constitute the better and what the conditions are upon which it depends, are matters with which life will ever concern itself. The reconstruction of living so that it will have the utmost value is the primary objective of philosophy.

In his monograph, “Foundations of the Theory of Signs”, Mr. Morris offers us a framework of ideas which is useful in analyzing many philosophic problems. On the basis of Morris' categories I want to show that it is both logically possible and desirable to make a distinction between two kinds of certainty. I will call them purely logical certainty and practical certainty (after Hume). They may be called syntactical certainty and pragmatical certainty also.

One thing which has struck me most as I have read the articles of the Encyclopedia of Unified Science is the complexity that can be discerned in many of the operations which for the purpose of the article are treated as elementary. It is apparent that Unity of Science, like every other discipline, has its own stock of “atoms of discourse”, suited to its own purposes. Experience in physics would prepare one to expect that for certain purposes it may be profitable to attempt to analyze these atoms further. The atom of discourse, or presupposition commonly made by most adherents of the Unity of Science movement, with which I shall be chiefly concerned, is with regard to the nature of “science“. My present concern with this matter has arisen from my extreme difficulty in communicating my meaning to other people. The difficulty has been a genuine puzzle to me, until quite recently a discussion with one of my colleagues disclosed a difference of attitude on fundamental matters so revelatory that I am encouraged to return again to the attack.

The recent far-reaching developments of Physics have produced the widespread impression that all those ideas of mechanics and mechanism, which were so influential in the nineteenth century, have now been completely abandoned, because they have proved to be quite inadequate as explanations, or even as mere descriptions, of the ultimate constitution of the physical world. “Has not modern physics”, asks Prof. Millikan, “thrown the purely mechanistic view of the universe root and branch out of its house?“ It is frequently contended, still further, that the place of these concepts has been taken by others, very closely approximating to biological, or even to psychological, interpretations of all natural phenomena; the physics of today, in short, and yet more of tomorrow, is essentially non-mechanical.

Charles Peirce was one of those rare individuals, an expert logician who is at the same time an experienced practical scientist. His logical acumen was apparent even to his contemporaries; while an early training in chemistry, astronomy, geodesy and optics, left him, as he declares, “saturated through and through with the spirit of the physical sciences.“ One is therefore hardly surprised to discover that he was deeply interested in scientific methodology—particularly in the logic of induction. Indeed, it would not be an exaggeration to say that some of his most significant contributions to philosophy were made in precisely this field. No apology is thus required for devoting attention to them. In the present paper I want to sketch his treatment of induction very briefly, and attempt a tentative estimate of its validity.

No account of the development of contemporary empiricism is adequate which neglects the writings and the influence of Charles Peirce. Although he is not easily pigeon-holed and can not be claimed as the exclusive property of any school or movement, it is appropriate that the hundredth anniversary of his birth should be commemorated at this Congress. For the movement of which it is a manifestation is engaged in a coöperative, intensive cultivation of the methods of the sciences with the help of the most advanced tools of modern logic; and Peirce's intellectual career was also a single-minded devotion to that task. It is fitting, also, that his birth-year be celebrated at Harvard by an international congress. For although he was denied the privilege of teaching at this university, much of his influence was propagated by William James and Josiah Royce, two of its great teachers; and however much he may have suffered from neglect during his life-time, his work surely merits recognition from a movement not confined by national bounds. It is characteristic of the best established sciences that though individuals may pursue researches in them independently of one another, the conclusions reached tend to support each other and to converge toward a common stream of sound beliefs; and such convergence is indeed the sole identifiable warrant for the confidence that some measure of the truth has been attained. It is therefore a happy sign that so many of the central ideas of the present movement have been independently developed on both sides of the Atlantic. One is not minimizing the contributions of the Vienna Circle in pointing out that many of its recent views have been taken for granted for some time by American colleagues, largely because the latter have come to intellectual maturity under the influence of Peirce.

If the truth of a given sentence, ‘P’ depends upon a certain non-linguistic fact, P then, how is the P without inverted commas involved in the statement, “ ‘P’ is true when P“? How is ‘P’ related to P? My answer suggests that any discussion of these questions leads inevitably to the ancient problem of particulars and universals.

There are no new fallacies under the sun, any more than there are any new methods of reasoning. Therefore, the Fluxive Fallacy is nothing new. Yet, pointing out the Fluxive Fallacy and giving it a name has a distinct advantage in that it directs one's attention to errors which, without the advantage of a definite name and description, might pass unobserved.

The prevailing philosophical mood among those physicists today whose interests are mainly in the field of modern atomic theory, is some form of positivism. This is true not only of the leaders in the field of quantum mechanics, as for instance Heisenberg, Jordan, and Dirac, in whose writings on the philosophical aspects of the recent revolutionary advances in physics the positivistic tendency is clearly visible, but also of the rank and file of competent students of the modern quantum theory.

It can not be our purpose to give here a complete account of the phenomenological history of mathematical doctrine. It will be enough to refer to the battle of opinions in mathematical theory which was waged within the last eighty-five years, since Riemann's inaugural lecture on Non-Euclidean Geometry. Furthermore, the revolution which Einstein's theory of general relativity created is indicative of the complete absence of any general awareness that mathematics as a science has any relation to social reality. If we are going to establish such relations, we are conscious of the fact that they would be hotly contended by many mathematicians.

What is the relationship of history to the phylogenetic evolution of man? Historians, like all specialists, are wont to restrict themselves to their own problems and, therefore, do not deal with this question. Only some popular books on the history of the world cross the dividing line between social and natural science. They start with the origin of the solar system, describe the development of the crust of the earth and of life, turn to prehistoric civilization and ancient Egypt, and eventually finish with the history of present times. It is striking that those expositions become more and more detailed the nearer they come to their end. Near the beginning one page describes ten million years, near the end ten months.