Human skin is the one authentic criterion of the universe which philosophers recognize when they appraise knowledge under their professional rubric, epistemology. By and large—except for a few of the great Critics and Sceptics—they view knowledge as a capacity, attribute, possession, or other mysterious inner quality of a “knower”; they view this knower as residing in or at a “body”; they view the body as cut off from the rest of the universe by a “skin”; all of which holds for philosophizing physicists and physiologists even as for the professionals of the arcanum itself. If this assertion seems crude, one may recall that there are times when a bit of crudity is a fair physic for an inflamed subtlety. In the case before us the factual crudity lies in the use of “skin” for a criterion, not in our calling attention to the fact. The “skin” that is so used is, indeed, that of ancient anatomical schematism, unaffected by the transformation of understanding which modern physiological research has brought about. Yet if philosophers cease thus crudely to employ it, all their issues of epistemology will vanish, and the very type of attack they make on cognition will be discredited; whereupon the task of determining the status of knowledge itself will pass from their hands to those of the scientists who have taken over so many regions of philosophical arrogation in the past. This is what I propose here to show.

The belief in the old type of a priori knowledge is gone. Cartesian innate ideas vanished with the severe criticism of Kant who held that only the form, not the content, of experience is known a priori. More recent criticism of Kant's a priori has taken place indirectly by way of the development of non-Euclidian geometries so that today there is no longer the belief that either the content or the form of experience is fixed and changeless or known with certainty a priori. But has the a priori phase of experience passed altogether? If not, what in recent thought has taken its place?

When phenomenology was introduced as a new science by Husserl its methods were applied first to objects of logic. Later phenomenological investigation expanded gradually to the fields of psychology, ethics, esthetics, and sociology (Scheler, Pfänder, Hildebrand a.o.). More rarely, objects of the natural sciences have been treated phenomenologically. Scattered indications of this kind are to be found in authors who do not belong to the most intimate circle of Husserl's school (Helmut Plessner, Kurt Goldstein, Walter Frost, E. Buenning). Extensively, however, the phenomenological method has been applied to objects of the natural sciences once only, namely by Hedwig Conrad-Martius, a favorite pupil of Husserl's, in her Realontologie (Ontology of Reality) and Farben (Colors). Yet this less known branch of phenomenology is particularly interesting. Husserl stressed the basic difference between phenomenological ideation (Wesensschau) on the one hand and psychological introspection and description of the immediate data of awareness on the other. The peculiarity and scientific productivity of phenomenological method, therefore, can be studied best in a field which is as far removed from psychology as possible. We shall try to analyze the papers of Conrad-Martius more fully and shall refer to other authors occasionally as illustrations.

It is my purpose to examine this law in those cases in which it is generally held to be untrue. I inquire what can be meant, in each case of a statement p considered, by denying the law, that is, by saying ‘Neither p nor —p‘. After separating the possible meanings of this declared indeterminacy, I go on to inquire, taking each possibility in turn, whether the law does in fact fail.

In my last talk I introduced you to the system of the sciences and then went on to chat about the first of the natural series of the sciences, namely physics. To-night I shall discuss the other partner of the pair which could be called “the physical sciences”, namely chemistry.

Of both of these sciences, physics and chemistry, it may be said that they are preeminently the study of matter-in-motion. Of both it may be said that the methods of study in the laboratory have a strong resemblance.

As I understand it, you have asked me for an honest, introspective—personal—account of how I think about anthropological material, and if I am to be honest and personal about my thinking, then I must be impersonal about the results of that thinking. Even if I can banish both pride and shame for half an hour, honesty will still be difficult.

In a recent article Professor M. C. Nahm, defending what he characterizes as an amplified version of the James' theory of the emotions, argues that teleological principles are required in any adequate definition of the emotions. Mechanistic principles may account for the physiological basis of emotional experience, it is maintained, but if we are to define the total experience, which includes a certain conscious content, we must go beyond the mechanistic hypothesis and regard the emotions as directed toward certain ends. He proposes to reveal the “epistemological core” of the problem of the emotions with the evident intention of indicating the lines which the development of the theory of the emotions should follow. It is the aim of this paper to scrutinize the general problem of the emotions in the light of Mr. Nahm's arguments and to consider specifically: (1) the alleged teleological implications of the problem, (2) the statement of the problem of the emotions as it is given in Mr. Nahm's paper, and (3) the present state of research as it may be relevant to the question whether Mr. Nahm's presentation makes for philosophical clarity or methodological advancement in science.

Meanings have an empirical genesis and status. This simple claim has often been denied or ignored. Some metaphysicians in their exaltation of the eternal have regarded meanings as essences, or eternal objects, or neutral entities, in a subsistential or supernatural realm that is changeless and has no roots in nature. Some logicians in their zest to manipulate meanings isolate them so completely as forms of reason, or as syntactical symbols that at no point is their connection with natural events made intelligible. Yet meanings, all meanings, have relation to mind. It is this empirical, psychological aspect of meaning that I shall analyze. The larger philosophic question as to what the relation of the psychological aspect is to the metaphysical or the logical will not concern us except indirectly.

The “determination to catch the world's multiplicity and variety in a single net appears to be an incurable bias of the learned mind.” The extremes to which a philosopher will go to make his net hold water should be nothing short of absurd to the literal minded who neglect “the climate of opinion” which shapes the very logic of the systems or who fail to sympathize with the deep underlying human needs which call forth the great philosophies. Most thinkers in this anthropological day make their bow to the fact of cultural conditioning and to the fact of personal and social surds in the thought of the past. We make our bow, and then proceed to forget that we are human individuals living in an historical period with its own unique strains and symphonies and discords: if only today's system can be shown to be scientific, it must then be beyond dispute.

A kinetic theory of permeability is developed both for the case where the cell membrane is a distinct phase and where it is simply the interface between cell and environment. A general expression for the diffusion current of a substance across the membrane is derived, which depends on two “coefficients of permeability” rather than one. Solubility and adsorption theories of permeability are shown to be special cases of the formulas. The permeability coefficients are expressed in terms of the difference of potential energy of the diffusing substance in the two phases; for a membrane of finite thickness they also involve the thickness, and the diffusion coefficient of the solute in the membrane.

We wish here to consider the theory of a population or system made up of individuals whose number and size change with time. As usual, the description of these changes will be referred to as the kinetics, whereas the description of the special circumstances under which unchanging (equilibrium) conditions subsist will be called the statics of the population. A third category, the conditions for a steady state, i.e., when the variables inside the system do not change, but linked variables outside (or at the boundary) do, will be described by what we shall call the rheostatics of the system. All three, statics, rheostatics, and kinetics are subdivisions of the general dynamics of the system.