Physiological Subjectivism

This article is a critique of what I call “physiological subjectivism.” Physiological subjectivists maintain some variation of the following positions: (i) Subjects only perceive elements contained in a set E (e.g., set E being the set of possible and actual “representations,” “appearances,” sensa, or percepta) and (ii) Subjects (namely neuroscientists and physiologists) have empirical evidence of Subjects’ nervous systems “producing,” “causing” (or causally determining), “shaping,” or  “filtering” all of the “representations,” “appearances,” sensa, or percepta perceived by Subjects. The following passages are excellent illustrations of physiological subjectivism:

“We never perceive the objects of the external world immediately, rather we perceive only the effects of these objects upon our nervous apparatus, and this has been so from the first moment of our life. By what means then have we been brought from the world of the sensations of our nerves to the world of reality? Obviously only through an inference; we must posit the presence of external objects as causes of our nervous excitation; for there can be no effect without a cause.” (Helmholtz, Philosophische Vorträge, 115-116) 

“It is natural to suppose that what the physiologist sees is in the brain he is observing. But if we are speaking of physical space, what the physiologist sees is in his own brain.” (Russell, An Outline of Philosophy, 146) 

“What you see when you look at a brain through a microscope is part of your private world….What I maintain is that we can witness or observe what goes on in our own heads, and that we cannot witness or observe anything else at all.” (Russell, My Philosophical Development, 18-19) 

“The whole of my perceptual world is...in my head and occupies a volume smaller than my head.” (Russell, The Analysis of Matter, 145) 

“The whole of a man’s visual space is, for physics, inside his head....All our percepts are in our head.” (Russell, The Analysis of Matter, 253)  

“We do not know much about the contents of any part of the world except our own heads.....Whoever accepts the causal theory of perception is compelled to conclude that percepts are in our heads....It follows from this that what the physiologist sees when he examines a brain is in the physiologist, not in the brain he is examining.” (Russell, The Analysis of Matter, 319) 

“The object of sense must be within my nervous system in order to be sensible...it is the nervous system itself sensibly affected. The hot felt is the tactile nerves heated, the white seen is the optic nerves so coloured….The sensible object then is…an effect in the nervous system.” (Case, Physical Realism, 22)

“What do we see when we look at a table? First and foremost, a lighted region containing some air, lit by rays coming partly from the direction of the table, partly from other sources; then the further boundaries of this region, surfaces of objects, including part of the surface of the table….And where is colour according to this scheme? Somewhere in the eye, as anyone who cares to strike his eye will discover….Thus what is directly apprehended is a modification of a sense organ, and its apprehension is a further modification of the nervous system...” (Ogden and Richards, The Meaning of Meaning, 176-178) 

“Whether beautiful or ugly or just conveniently at hand, the world of experience is produced by the man who experiences it. This is not the attitude of a skeptic, only of a psychologist. There certainly is a real world of trees and people and cars and even books, and it has a great deal to do with our experiences of these objects. However, we have no direct, immediate access to the world, nor to any of its properties. The ancient theory of eidola, which supposed that faint copies of objects can enter the mind directly, must be rejected. Whatever we know about reality has been mediated, not only by the organs of sense but by complex systems which interpret and reinterpret sensory information. Physically, this page is an array of small mounds of ink, lying in certain positions on the more highly reflective surface of the paper. It is this physical page which Koffka (1935) and others would have called the “distal stimulus,” and from which the reader is hopefully acquiring some information. But the sensory input is not the page itself; it is a pattern of light rays, originating in the sun or in some artificial source, that are reflected from the page and happen to reach the eye. Suitably focused by the lens and other ocular apparatus, the rays fall on the sensitive retina, where they can initiate the neural processes that eventually lead to seeing and reading and remembering. These patterns of light at the retina are the so-called “proximal stimuli.” They are not the least bit like eidola. One-sided in their perspective, shifting radically several times each second, unique and novel at every moment, the proximal stimuli bear little resemblance to either the real object that gave rise to them or to the object of experience that the perceiver will construct as a result….Our knowledge of the world must be somehow developed from the stimulus input; the theory of eidola is false.” (Neisser, Cognitive Psychology, 3-5) 

“A percept is the creation of a given neuronal system...” (Moutoussis, The Machine Behind the Stage: A Neurobiological Approach toward Theoretical Issues of Sensory Perception, 2) 

“A person’s entire life experience—everyone, everything, every experience he or she has ever known—exists to that person only as a function of his or her brain’s activity....Neurologist and Nobel laureate Sir John Eccles wrote that the natural world contains no color, sound, textures, patterns, beauty, or scent. Thus, color, brightness, smell, and sound are...created by complicated brain circuits.” (Martinez-Conde and Macknik, Entry on “Nonveridical Perception” in The Encyclopedia of Perception, Vol. I, 637-642) 

“Bitterness or sweetness are, like colors, creations of the nervous system. An analogous situation exists for smell.” (Goldstein, Entry on “The Private Nature of Perceptual Experience” in The Encyclopedia of Perception, Vol. I, 829)

And so, in the words of James Ward, “into the man’s head the whole world goes, including the head itself.” The following argument of mine is a demonstration of the self-undermining character of physiological subjectivism; indeed, we may say that the physiological subjectivist must answer the following question in the negative: “Is the truth of this theory consistent with the fact that I know it to be true?” (Taylor, Elements of Metaphysics, 90).

P1) If a Subject is committed to the position that (i) Subjects only perceive elements contained in set E, and (ii) Subjects have empirical evidence of B “producing,” “causing,” “shaping,” or “filtering” all elements contained in set E, then said Subject is committed to the position that B is not an element contained in set E.

If a Subject is committed to the position that (i) all elements contained in set E are “produced,” “caused,” “shaped,” or “filtered” by B, and (ii) B is an element contained in set E, then said Subject would be committed to the position that B—an element contained in set E—was “produced,” “caused,” “shaped,” or “filtered” by B. However, such a position is contradictory; for, B cannot be “self-produced,” “self-caused,” “self-shaped,” or “self-filtered.” Therefore, if a Subject is committed to the position that Subjects have empirical evidence of B “producing,” “causing,” “shaping,” or “filtering” all elements contained in set E, then he is committed to the position that B is not an element contained in set E.

P2) If a Subject is committed to the position that B is not an element contained in set E, then said Subject is committed to the position that Subjects cannot—in principle—perceive B.

If a Subject is committed to the position that (i) Subjects only perceive elements contained in set E, and (ii) B is not an element contained in set E, it follows that he is committed to the position that Subjects cannot—in principle—perceive B. For, if he were committed to the position that Subjects can—in principle—perceive B, then he would be committed to the contradictory position that B both is, and is not, an element contained in set E. Therefore, if a Subject is committed to the position that B is not an element contained in set E, then said Subject is committed to the position that Subjects cannot—in principle—perceive B.

P3) If a Subject is committed to the position that Subjects cannot—in principle—perceive B, then said Subject is committed to the position that Subjects have never perceived B “producing,” “causing,” “shaping,” or “filtering” all elements contained in set E.

If a Subject is committed to the position that Subjects cannot—in principle—perceive B, then it immediately follows that he is also committed to the position that Subjects have never perceived B engaging in any form of activity, let alone perceive B “producing,” “causing,” or “shaping” all elements contained in set E. Indeed, if he were committed to the position that Subjects can—in principle—perceive B “producing,” “causing,” “shaping,” or “filtering” all elements contained in set E, then he would be committed to the position that B is an element contained in set E. However, if he is committed to the position that B is an element contained in set E, then he would be committed to the position that B was “self-produced,” “self-caused,” “self-shaped,” or “self-filtered”—and such a position is self-contradictory. Therefore, if a Subject is committed to the position that Subjects cannot—in principle—perceive B, then said Subject is committed to the position that Subjects have never perceived B “producing,” “causing,” “shaping,” or “filtering” all elements contained in set E.

P4) If a Subject is committed to the position that Subjects have never perceived B “producing,” “causing,” “shaping,” or “filtering” all elements contained in set E, then said Subject is committed to the position that Subjects do not have empirical evidence of B “producing,” “causing,” “shaping,” or “filtering” all elements contained in set E.

Empirical evidence consists in evidence that one can see, hear, taste, touch, or smell; indeed, empirical evidence is perceptible evidence. However, if a Subject is committed to the position that Subjects cannot—in principle—perceive B, and that Subjects cannot—in principle—perceive B “producing,” “causing,” “shaping,” or “filtering” all elements contained in set E, then it follows that said Subject is committed to the position that Subjects do not have empirical evidence of B “producing,” “causing,” “shaping,” or “filtering” all elements contained in set E.

C1) Therefore, if a Subject is committed to the position that (i) Subjects only perceive elements contained in set E and (ii) Subjects have empirical evidence of B “producing,” “causing,” “shaping,” or “filtering” all elements contained in set E, then said Subject is committed to the position that Subjects do not have empirical evidence of B “producing,” “causing,” “shaping,” or “filtering” all elements contained in set E. [From P1—P4]

P5) But the position that (ii) Subjects have empirical evidence of B “producing,” “causing,” “shaping,” or “filtering” all elements contained in set E, and the position that Subjects do not have empirical evidence of B “producing,” “causing,” “shaping,” or “filtering” all elements contained in set E, contradict each other.

This is should be obvious. If it is true that Subjects have empirical evidence of B “producing,” “causing,” “shaping,” or “filtering” all elements contained in set E, then it is false that Subjects do not have empirical evidence of B “producing,” “causing,” “shaping,” or “filtering” all all elements contained in set E; and if it is true that Subjects do not have empirical evidence of B “producing,” “causing,” “shaping,” or “filtering” all elements contained in set E, then it is false that Subjects have empirical evidence of B “producing,” “causing,” “shaping,” or “filtering” all elements contained in set E.

C2) Therefore, if a Subject is committed to the position that (i) Subjects only perceive elements contained in set E and (ii) Subjects have empirical evidence of B “producing,” “causing,” “shaping,” or “filtering” all elements contained in set E, then said Subject is committed to a contradiction. [From C1—P5]

In fact, we can make a parallel argument against certain forms of Materialism that claim support from physiology:

All parts of Nature are “produced” by my body.

How could they not be? After all, according to Materialism, my percepta (i.e., what I perceive) are states and affections of my nervous system.

My body is itself a part of Nature.

How could it not be? After all, my body and its internal organs and nerves are themselves perceptible; for, if they could not be perceived, then they would be nothing to me at all. Indeed, if my body was not perceptible, then what empirical grounds would Materialism have for asserting that what I perceive depends upon my nervous system? We are thus left with the following absurdity:

All parts of Nature are “produced” by a “self-producing” part of Nature.

If you are interested in learning more about the general argument which my post expounds upon, please confer Chapter 22, “Nature,” in F.H. Bradley’s 1893 magnum opus, Appearance and Reality and Chapter IV, “The Physiology of the Sense Organs and the World as Representation,” in Volume III of F.A. Lange’s excellent work, The History of Materialism.