SOME QUESTIONS OF PSYCHO-PHYSICS.[80]
SENSATIONS AND THE ELEMENTS OF REALITY.
[80] This article is the substance of a private communication from Prof. Ernst Mach to the Editor of The Monist—published in the present form with Prof. Mach's consent. Translated from Professor Mach's MS. by Thomas J. McCormack.
I have read Dr. Carus's article "Feeling and Motion"[81] with care, and have also perused Clifford's essay on "The Nature of Things in Themselves." Let me attempt to present the points in which our agreements and differences consist.
[81] The Open Court, Nos. 153 and 154.
To begin with, I state with pleasure that the monistic tendency of both endeavors is in the direction that appears to me to be the true one and that is most likely to afford elucidation. Consequently, agreement in matters of detail is of subordinate importance and is only a question of time.
Let me cite, first, a few passages from "Feeling and Motion" to which I give my full assent. They are the following:
"The interconvertibility of motion and feeling is an error."
"Feeling is real as much as are matter and motion."
"Its reality accordingly is most immediate and direct, so that it would be ridiculous to doubt it."
"Man's method of understanding the process of nature is that of abstraction."
"Every concept is formed for some purpose, and every concept by serving one purpose necessarily becomes one-sided…. We must bear in mind…. (1) the purpose it has to serve, and (2) that the totality of things from which abstractions can be made is one indivisible whole…. We must not imagine that the one side only is true reality."
Some years ago I should also have agreed in toto with the passages in which Dr. Carus speaks of the animation of all nature, and of the feeling that accompanies every motion. To-day this form of expression would not, it seems to me, correctly characterise the matter. If I were now prematurely to advance a definitive formulation, I should fear lest, so far as myself and perhaps others are concerned, important aspects might remain concealed.
I shall next cite the passages with respect to which I do not agree with Dr. Carus, and then I shall endeavor to state wherein our differences of opinion consist:
"All series A B C … are accompanied by α β γ." [The A B C … series of Dr. Carus has a different meaning from mine.]
"We may represent motion or we may represent mind as the basis of the world, or we may conceive them as being on equal terms." [I cannot agree with a co-ordination of "motion" and "mind.">[
"They [viz. feeling and motion] are as inseparable as are the two sides of a sheet of paper." [Fechner says, "As inseparable as the concave and convex sides of the same circle." This appears to me an inapposite simile in so far as a duality is predicated where in my view a unity alone exists.]
My view of the problem is as follows: We have colors, sounds, pressures, and so forth (A B C …), which, as simplest component parts, make up the world. In addition thereto, percepts (resolvable into α β γ …), feelings, and so forth, more or less composite. How α β γ … differ from A B C … I will not define here, for I do not know exactly. It is enough for the time being that they do differ from A B C …, as the latter do from one another. And let us now leave α β γ … entirely out of account and put ourselves in a time and state in which there are only A B C. Now I say, that if I see a tree with green leaves (A), with a hard (B), gray (C) trunk, that A B C are elements of the world. I say elements—and not sensations, also not motions—because it is not my purpose at this place to arrive at either a psychological or a physiological or a physical theory, but to proceed descriptively. The every-day man, indeed, takes greenness, grayness, hardness, or complexes thereof it may be, for constituent parts of the world—for he does not trouble himself about a psychologico-physiological theory—and does not learn moreover anything more about the world; from his point of view he is right. Similarly, for the descriptive physicist the question is also one merely of the dependencies of A B C … on one another; for him too A B C …, or complexes thereof, are and remain constituent parts of the world.
If, however, I close my eye (K), withdraw my feeling hand (L), A B C … disappear. If I contemplate A B C … in this dependence they are my sensations. This is but a special point of view within the first.
According to my conception, therefore, the same A B C … is both element of the world (the "outer" world, namely) and element of feeling.
The question how feeling arises out of the physical element has for me no significance, since both are one and the same. The parallelism stands to reason, since each is parallel to itself. It is not two sides of the same paper (which latter is invested with a metaphysical rôle in the simile), but simply the same thing.
A perfect physics could strive to accomplish nothing more than to make us familiar beforehand with whatever it were possible for us to come across sensorily; that is, we should have knowledge of the interrelation of A B C. A perfect psychology would supply the interrelation of α β γ. Leaving out of account the theoretical intermediaries of physics—physiology and psychology—questions like "How does feeling arise from motion" would never come up. However, the artificial inventions of a physical or psychological theory, must not be introduced into a general discussion of this character—for they are necessarily "one-sided."
I may now set forth my differing point of view with regard to the idea of "motion." A motion is either perceptible by the senses, as the displacing of a chair in a room or the vibration of a string, or it is only supplied, added (hypothetical), like the oscillation of the ether, the motion of molecules and atoms, and so forth. In the first instance the motion is composed of A B C …, it is itself merely a certain relation between A B C …, and plays therefore in the discussion now in hand no especial part. In the second instance the hypothetical motion, under especially favorable circumstances, can become perceptible by the senses. In which case the first instance recurs. As long as this is not the case, or in circumstances in which this can never happen (the case of the motions of atoms and molecules), we have to do with a noumenon, that is, a mere mental auxiliary, an artificial expedient, the purpose of which is solely to indicate, to represent, after the fashion of a model, the connection between A B C …, to make it more familiar to us. It is a thing of thought, an entity of the mind (α β γ …). I cannot believe that this is to be co-ordinated with A B C … in the same way as A B C … among each other are. Putting together motion and feeling goes as much against me as would say the co-ordination of numbers and colors. Perhaps I stand quite alone in this, for physicists have accustomed us to regard the motions of atoms as "more real" than the green of trees. In the latter I see a (sensory) fact, in the former a Gedankending, a thing of thought. The billions of ether-vibrations which the physicist for his special purposes mentally annexes to the green, are not to be co-ordinated with the green, which is given immediately.
When a piece of zinc and a piece of copper, united by a wire, are dipped in sulphuric acid and deflect a magnetic needle in the vicinity of the wire, the unprepossessed discoverer of the fact discerns naught of motion beyond the deflection of the needle and the diffusion in the fluid. Everything reverts to certain combinations of A B C. Electricity is a thing of thought, a mental adjunct; its motion another; its magnetic field still another. All these noumena are implements of physical science, contrived for very special purposes. They are discarded, cast aside, when the interconnection of A B C … has become familiar; for this last is the very gist of the affair. The implement is not of the same dignity, or reality, as A B C …, and must not be placed in the same category, must not be co-ordinated with it where general considerations are involved to which physics with its special objects does not extend.
The green (A) of the tree is not only adjoined to the presence of the sun (B), but also to the deflection of the needle (X), by my optic nerve. Familiarising intermediary connections to-day by motions, to-morrow by some other means, is the business of the special sciences, and can only disturb and obscure a general discussion. What should we say of a cosmology from a pharmaceutical point of view? In principle, this very thing is done, it seems to me, when physical augers and saws are employed in all fields of work, as is universally the case.
So much for the juxtaposition of motion and feeling. Perhaps I alone am right, perhaps I alone am wrong.
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According to my conception accordingly "material" processes are not "accompanied" by "feelings," but are the same (A B C …); only the relation in which we consider them makes them at one time physical elements and at another time feelings.
The relation in which "percepts" and "feelings" as distinguished from "sensations" stand to sensations, is not clear to me. I am much inclined to regard these feelings as a species of sensation (co-ordinate with sensations). How the representative percepts of imagination and memory are connected with sensations, what relation they bear to them, I dare venture no opinion. The relation of α β γ … to A B C … is the point regarding which I do not feel sufficiently sure. Regarding A B C … (world of sense in its objective and subjective significance) I believe I am clear.
Dr. Carus in a private letter to me says: "It almost seems as if you transform all A B C … series into the corresponding α β γ … series."
This is not the case. I designate by α β γ … representative percepts (not sensations), and say simply that A B C …, the same A B C …, play, according to circumstances, now the rôle of physical elements, now the role of sensations. I call A B C …, therefore, elements, pure and simple.
Mine is not the Berkeleian point of view. The latter has been mistakenly attributed to me time and again, the separation that I make of A B C … from α β γ … not having been sharply discriminated and it not having been borne in mind that I call A B C … alone sensations, not however α β γ. Clifford, with his "mind-stuff," approaches very near to Berkeley.
Monism, as yet, I cannot thoroughly follow out; because I am lacking in clearness with regard to the relation of α β γ … to A B C …, which can only be supplied by further physiologico-psychological investigations; but I believe that the first step towards a competent monism lies in the assertion that the same A B C … are both physical and psychical elements. As regards the psychical "accompanying" the physical, the question How? continually recurs. Either they are two incompatible things (Dubois) or their relation is bound up in a third thing ("thing-of-itself"). By viewing the matter as two sides of the same thing, not much more is gained, to my mind, than a momentary satisfaction.
All non-monistic points of view are, in my opinion, artificial constructions, which arise by investing with very far-reaching extensions of meaning psychological or physical special-conceptions, which have a limited value, applicable only within the department in question for the elucidation of the facts of that department. The overvaluing of psychological conceptions leads to spiritualistic systems, the overrating of physical conceptions to materialistic systems. Naturally in the latter systems motion plays a great rôle; for through a mistaken conception of the principle of energy, people have come to believe that everything in physics can be explained by motion. But explanations by motions have, as a matter of fact, nothing to do with the principle of energy. The majority of physicists, it is true, believe and disseminate this opinion. If, when a physicist speaks of motion and nothing but motion, the question is asked What moves? in ninety-nine cases out of a hundred nothing palpable or demonstrable is brought forward in answer, but hypothetical atoms or hypothetical fluids are adduced which execute motions still more hypothetical. Even in the domain of physics itself, the business of which is to proceed from the sensory and to return to the sensory, I can regard these "motions" at best only as provisorily tolerated intermediaries of thoughts, that have no right to be ranked on equal terms with reality, let alone placed above it.
Still less can I allow "motion" the right to create a world-problem where none exists, and thereby to conceal the real point of attack in the investigation of reality.
I may add that some years ago I took exactly Dr. Carus's point of view, which I presented in a lecture on Psycho-physics published in 1863 in the Oesterreichische Zeitschrift für praktische Heilkunde.
With regard to Clifford I may make the following remarks. The notion "eject" pleases me very much. I have long had the idea in mind, but have not defined it because its limitation is not clear to me; nor has Clifford given me any light on the subject. Is the representation in us of the material nature of things we cannot lay hold of (the sun, the moon) to be called an eject? Are the abstract concepts of physical hypotheses, which in their very nature can never become sense-affective, ejects? Such things are abstract in widely differing degrees, and are bound up with the sensory in very unequal proportions; the impossibility of becoming sense-affective is partly absolute, partly only relative, that is, it exists for the time being.
I do not at all agree with Clifford's notion "mind-stuff"; in this I wholly concur with Dr. Carus. It is not unbiased philosophising to come down in the end to a psychological notion as comprehensive of the world,—a notion on the face of it pre-eminently one-sided.
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In connection with the subject under discussion, I might incidentally make mention of Mr. Charles S. Peirce's article "The Architecture of Theories" in the last number of The Monist. One Mr. Peirce, a mathematician,[82] has made some very valuable investigations, similar to Grassmann's. This author's view of the evolution of natural laws does not strike me as so singular. If predominance be given in our conception of the world to the spiritualistic or psychical aspect, the laws of nature may be regarded as tremendous phenomena of memory; as I attempted some years ago to set forth in a lecture of mine. The idea of their evolution is then very near at hand. Of course I do not think that for the time being we can gain much light from this view. For the present the "scientific method" in the grooves of which we have moved for three hundred years, continues to be the most fruitful. It is advisable to be very cautious in advancing beyond this. It is for this reason also that I do not think very much of the fruitfulness of the idea that the entire world is animated and feeling. We have as yet too little insight into the psychical, and still less into the connection between brain-organisation and brain-function and psychical process. Of what advantage to us is the assumption of feeling in cells in which every clue is missing by which to proceed from the psychical assumed to the physical connected with it. It seems to me that the physical and psychical investigation of sensations is for the time being the only thing that can be entered upon with any prospect of accomplishing anything. In this we shall first learn the proper formulation of questions that are to form the subject of further investigations.
[82] Mr. Benjamin Peirce, father of Mr. Charles S. Peirce.—ED.