An instrument is any object which makes possible the attainment of desired ends. It is not essential to the being of the instrument that it be inanimate, worked over, or its mode of operation understood. A pigeon can carry a message; a stone as well as a hammer can be employed to break a glass; a child can start an automobile. The instrument need not function in the interests of men, be set into operation by living beings, or even be used at all. Leaves serve some insects as umbrellas do men; the rays of the sun may turn a screw; a new knife has not yet had a chance to cut. A cow is an instrument for the production of milk, a hen for the production of eggs, though neither is inanimate, worked over, nor its operation understood; they can serve the interests of other animals, are able to initiate their own movements, and may not yet have had occasion to produce the desired results. But they are instruments because they are acknowledged means for the production of the desired milk and eggs.

According to the Laplacian definition, the probability of an event is the ratio of “favorable” cases to possible cases. It is obvious that the definition presupposes the equal probability of the possible cases; and to make the definition of probability depend upon the conception of equal probability has the appearance, at least, of a vicious circle. Moreover it is hard to see how we can assure ourselves that each possible case is really no more and no less probable than any other. But even if we define probability as the relative frequency of occurrence of events under a given set of conditions, or of true conclusions from premises of a given type, we still require the conception of equal probability, unless indeed we choose to renounce entirely the mathematical expression and calculation of probabilities.

The theory of the conservation of energy and the Second Law of Thermodynamics have been described as the two most firmly established “findings” of modern science. Scientists frequently refer to them, not as theories or assumptions, but as facts. During the last two decades of the nineteenth century, however, Edmund Montgomery—an unsung Texas philosopher—repeatedly challenged, not only the notions that energy is convertible and is indestructible, but the very idea that there is such a thing as energy which can be imposed ab extra upon matter. For his trouble he received censure and ridicule on every hand; friends usually apologized for this eccentricity of his. Montgomery, of course, has not been entirely alone in criticizing the theory of the conservation of energy, though he was the first to make a persistent attack on the merits of the theory as a principle of scientific explanation. Busse, for one, contended that if, as he thought likely, the theory were incompatible with psychophysical interactionism, it should be discarded on the grounds that the evidence in its behalf is far from compelling. Emergent evolutionists remind us occasionally that it is still within the province of reason to question this great dogma notwithstanding the fact that it is a god at whose feet many scientists worship with blind and jealous devotion. Of all these critics Montgomery attacked the theory where its greatest weaknesses lie.

While the members of the school of Logical Empiricism may differ in various details, nearly all of them are opposed to metaphysics on the ground that a scientific metaphysics is the only possible one. All philosophy is to become scientific. This assumption is based on their epistemological criterion of verifiability which appears to be a basic doctrine of this school. The implications of this doctrine have not been worked out in detail by many, but one of the most explicit accounts has been given by A. J. Ayer in his book on Language, Truth and Logic, which can be taken as a representative work in its attack on metaphysics.

The contentions of this paper are essentially two. One is that truth does not consist of verifiability—and still less of verification—in the sense in which this has been maintained by some pragmatists, operationalists, and positivists. The other is that in a certain other sense of “verifiability”, which will be described, truth is the same thing as verifiability. The paper, it should be understood, attempts only to make clear what is and what is not the relation between truth and verifiability. It does not attempt in addition to carry the analysis of verification itself to the point where it would, by implication, furnish a terminal answer to the question, what is truth. The latter task, because of space limitations, must be reserved for some future occasion.

To bring clearly before the mind what is meant by class and to distinguish this notion from all the notions to which it is allied, is one of the most difficult and important problems of mathematical philosophy.”

When Russell wrote this in 1903, he could illustrate the difficulty of the problem by his own confusing attempt at a solution. He was able to demonstrate the importance of classes for mathematical philosophy in his later work: the definition of cardinal number as a class of classes similar to a given class served him as a cornerstone for the derivation of mathematics from logic.

Like the rest of us, scientists, theologians, and metaphysicians have grown worried about the political affairs of the world, and have set their wits to work to find ways of combating dangers abroad and at home. Some of them organized a Conference on Science, Philosophy and Religion in their Relation to the Democratic Way of Life, and met in the fall of 1940 to hear a number of papers about themselves and their work. They met in the hope of finding a common basis for endeavor, so that they might co-operate in maintaining that way of life which we commonly call ‘democracy’.

Although it is difficult to exaggerate the similarities between the philosophical doctrines of contemporary scientific empiricists and those which were expounded by Sextus Empiricus, the Greek physician and sceptic of the third century A. D., Sextus seems to have been neglected by most historians of empiricism. An account of his position may be of some pertinence at the present time, for a striking parallel can be drawn without any distortion. His most significant contributions are: first, the positivistic and behavioristic theory of signs which he opposed to the metaphysical theory of the Stoics; secondly, his discussion of phenomenalism and its relation to common sense claims to knowledge; and, thirdly, his account of the controversy over the principle of extensionality in logic, where the anticipation of contemporary doctrines is perhaps most remarkable.

About a decade ago Sir Frederick Soddy, a distinguished creative scientist, wrote: “The exploiters of the wealth of the world are not its creators. ... So far the pearls of science have been cast before swine, who have given us in return millionaires and slums, armaments and the desolation of war.” Today we see the end-product of this process: Unrealized democracies fighting desperately against a ruthless imperialism based on the most extensive functional exploitation of science and scientists the world has ever known.

The claim of this communication is to present an outline of a program of research and development of thermodynamics. The scope of this and subsequent discussions will be “materialistic,” by which the author means a combination of both formal and experimental aspects.

The present paper deals with the determination of the size and charge of a single submicroscopic particle, measured in a small horizontal condenser of a diameter of approximately 8 mm., using the author's method first stated April 1910. To obtain the highest sensitivity, author used solid particles (spheres) of an order of magnitude under 3 × 10–5 cm. and found charges less than that of the electron. Various objections were raised against his findings, namely that the particles investigated were not spheres, and that their density was not that of the macroscopic substance, so that his findings of charges less than the electronic charge were merely imaginary. The author has succeeded in precipitating and measuring a particle after having observed it in the condenser under normal and also very high gas pressures. The particles were shown to be perfect spheres. A new method is indicated whereby it is possible to determine the size of sub-microscopic spheres by pushing together two equal spheres with a micromanipulator; the two diffraction disks overlap and render it very easy to determine the actual size. It is also possible to show that the density of each individual sphere is that of the macroscopic substance, since it can be computed easily from the velocity of fall at high gas pressures (according to Stokes' law). These two data being accurately determined, the author still found charges considerably less than the electronic charge, and the deviations are too great to be accounted for by errors of observation. The reason that the author has used a solid substance (red amorphous Se) and not oil, which is a liquid, was in the first place, that liquids evaporate, and therefore do not yield correct results, and secondly, because liquid spheres are not certain to preserve their sphericity when precipitated. Thus charges less than that of the electron are to be considered as actually existing.

According to generally accepted views every material body has always just as much North as South magnetism, meaning that the total value of the North and South magnetism is always zero (div H = 0). One says therefore that there is no “true magnetism”. A body directs itself in the direction of the magnetic lines of force like a compass needle but it does not move from its place. On the other hand, it is known that there are electrically charged bodies (positive or negative electric ions) which move in homogeneous electric fields along the lines of force. There is thus a preponderance of positive or negative electricity on ions. One says also that there exists “true electricity”. A movement of charged matter in a homogeneous field is called a current. Consequently until now electric currents were known to exist, but no magnetic currents.