Herr Lasswitz on Energy and Epistemology

Herr Lasswitz draws two conclusions in his epistemological study of the modern theory of energy (see notice of articles under Psychological Literature) which have a psychological value. The first is that the substitution of energy for mass in formulating equations between the so-called 'forces of nature' obviates the fallacy which follows a too common interpretation of physics, that its fundamental unit is expressed in terms of the sensation of touch. A molecule or atom is of course as far beyond the possibility of a sensation of touch as it is beyond one of sight. Nor are we justified in carrying beyond the limits of perception, by magnifying in imagination, those sensations which have followed the exact determination of the phenomena of nature down to this threshold; for these very determinations demonstrate that below this point the balancing of energies between spatial objects, among which is the human organism, does not allow a reading into terms of sensation.

We are forced by this into the conclusion that physics in so far as it involves determinations which run out to the indefinitely small must always abstract from the quality of the sensation, and leave simply the rational statement, in terms of magnitude, of the dependence of the processes of nature upon each other.

We wish to draw one important corollary from this proposition. The impossibility of dividing the sensation up into equal parts — of dividing one sensation up into the several sensations which should compose it — has been already maintained with sufficient emphasis in criticism of Fechner's Psycho-physical Law, but the essential difference which lies between the methods of the natural sciences and those of psychology expressed in the threshold values of the various sensations (that is, the absolute beginnings of sensations contrasted with the possibility of reducing the stimulus to an indefinitely small magnitude) has not be sufficiently insisted upon.

The difference is perhaps most succinctly brought out by the contrast between the quality in sensuous experiences and the same in physics. The first is static in its value — that out of which a naive dualism constructs matter. The second is but the law in the midst of change. It is only by the infinitesimal concept that the physicist is able to express color, sound, resistance (touch), etc. The problem of the physicist is to make a magnitude out of change — by means of the mathematical formula. He has, in expressing color, only a periodicity

(173) in a process of radiation upon which to base the static element that makes up the content of most objects of perception.

The problem of the experimental psychologist is just the opposite. It is to find a change that may be expressed in law, a magnitude which cannot be broken up. Sensation, emotion, feeling are magnitudes which within themselves suffer no disintegration, can be broken up into no parts. The psycho-physicist has hit therefore upon the ingenious expedient of paralleling the infinitesimal state in the physical phenomena by the just observable differences in the psychical. The results of this method of research have, however, but poorly rewarded the remarkable ingenuity expended upon it. And a moment's thought will reveal the inefficiency of this tool borrowed from the physical sciences.

The validity of the infinitesimal statement lies in its definition in terms of the law. The process is but arrested to assert the relations which lie between its different moments. How different the just observable difference in psycho-physics! Here there is no law in which to define the state, but we are confronted by a series of equations in which a = b, and b = c, but in which a < > c [1]. Instead of defining the arrested process in terms of its formula, psycho-physics has striven to formulate a law out of a series of states that can be defined no more nearly that in the assertion that they are different. How futile would be the attempt to build up the law of the circle out of successive relations of the co-ordinates, these not being defined in terms of the angles made with a vanishing secant, but only in the assertion that the successive coordinates are just perceptibly different from each other! Measure these co-ordinates as exactly as one may, and he has still no content in the successive states and can reach such a content only when he can define the relations of the co-ordinates absolutely by means of the law of the curve.

In a word, the physicist has abstracted the entire mathematically statable content of the sensation — and only this; and for the psychophysicist to strive to use that which is left for the same purpose is to make it evident that he does not comprehend the relations of the two fields. We trust with Herr Lasswitz that the substitution of energy for mass in the physicist's statement will carry home the nature of the scientist's abstraction.

The unity which underlies the physical object or system (Gebilde) is thus reduced to a rational categorization which is the framework of consciousness — a framework which is given and of which the unity of the individual consciousness is but an expression. This is the

(174) second of Herr Lasswitz's propositions, and he draws from it the solution of the problem of the relations of the unity of the object to the unity of the individual consciousness. It is really only a deduction from the first proposition. Granted that the unity of the full sensuous object is that of the individual consciousness, the categorization in terms of space, time and energy abstracted from this must fall under the same unity.

An important corollary to this, which also fills out the criticism passed upon the method of psychophysics, is to be found in the continuity of the methods of exact science even if carried up to the full psychical phenomenon.

Professor Baldwin has identified Kant's transcendental unity of consciousness with attention. If we now define attention as the domination of any one act over all tendencies to action with the organism at any one time, and define the object as a group of activities co-ordinated with reference to some particular act [2], we have a psychophysical fact which can be stated in terms of the food-process by the biologist and of the compensation of the intensities of energy by the physicist. For an object which is a co-ordinated group of activities must have developed in the process of evolution under the same law which governed the development of the whole organism. This same process must serve as a formula for the development of the psychological object, constructed as it is out of the activities which the search for food in an increasingly complicated environment has called out.

But the more abstract laws of physics are no less applicable than those of evolution to objects so constructed. A single instance may be found in the parallel set of relations of the various energies of light, sound, etc., to that of mass; of the sense-organs of color, tone, etc., to that of touch; of the sensations of color, sound, etc., to those of contact.

These may be read into a relation between an energy acting continuously along a single line and periodical energies of radiation acting along innumerable lines. Whether these latter may be expressed in terms of vibrations of particles of a ponderable medium and so to be reduced to mass, or not, the ideal of physics will hardly be reached

(175) before they are reduced to some single form of energy. We shall have something strictly analogous to the relation between direct action and action through media. The assumption that all senses may be reduced to that of touch or contact has long been practically unquestioned. And here we have the relation between sense-organs that receive direct continuous contact and those that respond to radiating periodic stimuli, serving as before to express immediate relation and that through media; or, in other words, the relation between physiological reactions upon direct contacts and those upon medial contacts which serve to make direct contacts possible. Lastly we have the sensations of color and sound which have a character symbolical with reference to touch, and activities which they call forth mediating the more important activities which are called forth by the stimuli of contact.

If, now, the psychological object be formed out of full sensuous activities responding to stimuli which affect the different sense-organs; if these reactions take place in a system built up by action upon its environment, and if the relations of its environment to it are expressed in the fundamental laws of energy, evidently those reactions and those objects must be functions of the laws of physics. A statement of the object in terms of our activities enables us to apply the laws of the exact sciences to their development and relative values.

George H. Mead
University of Michigan.



  1. Natorp's Einleitung in die Psychologie, p.84.
  2. Professor James has shown that our object changes completely with the activity which it represents, that a paper which presents a surface for the pen is quite a different object from paper used for kindling a fire.

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