The Causal Basis of Perception
That men and animals perceive the world around then is a wonderful and amazing fact. The capacity to be directly aware of reality is an achievement of living beings that has always fascinated me. What is it that makes the achievement of perception possible? What is happening when we perceive? What are the causal principles operating at the physical, biological and psychological levels?
To seek the answers to these questions is to want to understand perception. In my search for such an understanding, I have met few individuals who share my quest. Modern philosophical skepticism has so infected today’s culture that it is extremely rare to find a scientist who is courageous enough to declare that men perceive reality. Philosophers have so succeeded in bullying people into believing that direct perception of reality is impossible, that the perceptual level of awareness is unreliable, and that perception must be combined with and supplemented by some sort of additional cognitive processes before it can render reliable testimony as to the structure of our external world and the individuals physical relationship to it. Which sorts of augmentation of perception by other cognitive processes depend on the points of view of the individual schools of philosophy.
The Humean empiricists would say that perception, initially an experience of ‘blooming buzzing confusion,’ is supplemented by sensory associations, cognitive habits and temporal expectations. These are added by the mind and are not in the perceptions themselves. Hume held that all that we know is our perceptions themselves, and have no warrant from these to attribute external independent existence of the objects of these perceptions.
“Nay, even to these objects we cou’d never attribute any existence, but what was dependent on the senses; and must comprehend them entirely in that succession of perceptions, which constitutes our self or person. Nay farther, even with relation to that succession, we cou’d only admit of those perceptions, which are immediately present to our consciousness…” David Hume, A Treatise of Human Nature
If Hume is right, how then do we all seem to perceive the same world? Humeans would reply, because we all, sooner or later, come to experience the same associations, impose the same habit of sensory coherence, and thus form the same expectations. Thus our entire sense of the world at the level of perception is essentially an act of faith. Faith in subjective expectations is all that we can claim at the perceptual level. We can never validly escape from our senses, our perceptions into an external objective world. Thus the Humean view of perception reduces essentially to the doctrine of solipsism. A wholy inadequate and ultimately self-refuting doctrine.
Kantian nativists, on the other hand, would argue against Hume that we all see the same world in the same way because we all have innate (a priori) filters and forms that force us to see the world in terms of these innate ideas, which include a priori cognitive structures that force us to see the world as arranged in three-dimensional space, as existing sequentially according to the dimension of time, and to see the temporal sequences in terms of the innate category of causality. Shape and form are also imposed on our sensations to organize our perceptual experiences into a panorama of external phenomenal three-dimensional spacial objects. Thus perception is a product of the innate ideas and filters of the mind working on the data of sensations to yield a conviction of stable external reality. In fact, Kant would say, we cannot ever know the object in itself (‘the thing in itself’) but only the phenomenal object (or ‘phenomenal thing’) produced by the innate, a priori, mechanisms of our mind.
Thus to the empiricist and nativist alike, the senses cannot, by their very nature, ever by themselves give us reliable knowledge about the real external physical world of objects and events. Neither can any combination of Kantian nativism (phenomenalism) and Humian empiricism (skepticism) ever lead to any theory of veridical (‘truthful correspondent’) perception. Since most of today’s philosophers and psychologists represent different flavors and mixtures of skepticism and phenomenalism (not to be confused with phenomenology), including modern cognitivism (the computer model of consciousness and conscious regulation), behaviorism (essentially Hume extended by operant conditioning), and psycho-neural identity (pushing the problem down into the nervous system and ultimately to neurophysiology), all of which embrace operational or mechanistic reductionism (via innate mechanisms or associative mechanisms) and seek to deny perception as a form of conscious cognition of external reality (including the reality of our own bodies and ‘selves’ as part of that reality), leaving the landscape of perceptual theorizing is disappointingly bleak and, I might add, sterile.
Among theoretical psychologists influencing the contemporary scene, the one bold and eloquent exception to this scientific timidity is found in the work and legacy of Professor James J. Gibson. Gibson’s writings (the product of a lifetime of experimental research and deeply original and often unorthodox thought) represent a new departure in perceptual theorizing. Gibson rejected the entire spectrum of the nativist-empiricist mainstream by rejecting the fundamental premise that all representatives of this spectrum share, viz., that (1) what is given to the senses is inadequate to account for all that we perceive, (2) that, therefore, the sensory givens must be supplemented or ‘enriched’ by some non-sensory process, and, (3) therefore, that all perception is contaminated (invalidated) by subjectivism.
In contrast to these subjectivist views, Gibson begins by recognizing the fact of direct perception of our environment, our place in it, and our relationship to it, and proceeds to ask: How is perception achieved? Gibson recognizes the following facts: (1) that perception is the product of what is given to the senses, (2) that what is given to the senses are patterns of energy, (3) that what is given is not static, but dynamic, especially with respect to the transformations of the given energy patterns in response to human action (self-generated movement) and (4) that the proper questions to ask in this regard are: (a) What are the variables in the available energy that carry information about objects and the environmental layout as well as the perceiving organism’s relationship to the environment? and (b) How are these energy variable picked-up by our perceptual systems resulting in direct awareness of our environment and ourselves? Gibson’s magnum opus, The Senses Considered as Perceptual Systems, is an integration of his many years of observations and conclusions reached in his continued effort to answer these questions.
The value of Gibson’s rich scientific work lies not only in the original conclusions he draws, but also in his way of thinking about and making observations about perception. His sight of the facts is always first-hand, which gives his presentation of these fact a freshness and clarity only possible to a man who sees with his own eyes and who thinks for himself. It is a tribute to his own spirit that the last sentence in his book reads: “This book is dedicated to all persons who want to look for themselves.” (Gibson, 1966, p. 321).
Inspired by Gibson, I have looked and thought for myself about the nature of perception. This paper [ first written in 1975 and here rendered as a series of blog pages] is an attempt to present, in an integrated format, the fruits of the thinking I have done in trying to understand the causal basis of perception. Although I gratefully acknowledge my deep indebtedness to J. J. Gibson for many of my conclusions and for some of my methodology, it is not my intention in this paper to restate Gibson, whose eloquent writing requires no reformulation. Rather, it is because I believe that I have managed to arrive at a sufficient number of original and (hopefully) valuable insights, integrations and conclusions about perception to justify my setting them down, that I have written this theory of the causal basis of perception.
[From a thesis submittal to the Department of Psychology, Brooklyn College, entitled: The Causal Basis of Perception: A New Integration on a Gibsonian Base, by Jack H. Schwartz, September 10, 1975.]
Prolegomena to Understanding the Nature of Perception
In this year, 2015 roughly 40 years after the publication of my thesis, I find it essential to emphasize the following prolegomena implicit in my 1975 thesis. 1. the only proper approach to the problem of perception is to ask honestly, from a scientific perspective, how our senses work; how they give us direct awareness of the external world. 2. In each case of sense-perception, we must ask ‘What are our senses detecting whenever we have a given sensation of color, of tone (pitch), of ‘cold’, of ‘warmth’, of ‘slant’, of ‘shape, of ‘distance’? 3. We must not presume nor second guess what our senses are responding to. 4. We must not impose a rationalist model of ‘how the world ought to look and feel to a valid sensory system.’ 5. We must not attempt to extend to perception the principles and facts of physics or chemistry, nor assume that physical or chemical ‘facts’ (nor even neurological facts) must yield corresponding one-to-one sensory ‘facts.’ 6. We must not embrace nor apply an a priori doctrine of sensory integration based on an a priori theory of ‘sensations’ and ‘sensory (or cognitive) integration. For example the naive epistemological assumption that perceptions are products of the integration of sensations. 7. Once we discover that our separate senses each respond to specific forms of energy, we must not assume that ‘valid’ or ‘objective’ perception must consist of some form of direct sensory responsiveness to the absolute properties of that form of energy (with respect to intensity, frequency, duration, pattern, distribution, or any other so-called simple objective fact about that energy). 8. Organisms including their sensory systems consists of complex hierarchical, interacting, integrated levels of organized subsystems possessing causal efficacy at each level. 9. Hierarchical systems, while standing in a holistic relationship to the organism as a whole, do not have a centralized (general) nor an atomized (local) system of causality. Rather causal principles emerge at all levels of the hierarchy and are ‘handled’ at each level depending on whether the causal event is propagating downward (to deeper levels of the hierarchy) or upward to broader levels of the hierarchy.
To apply these prolegomena, let’s look, for example, at the facts of the so-called thermal touch illusion, induced by moving each of our two forearms, one resting in and adapted to a warm water bath and the other resting in and adapted to a cool water (such that neither arm at this point feels either ‘warm’ or ‘cool’, to a a common tepid water bath. The resulting sensations for the two forearms is as follows: the one coming from the physically colder water bath will feel the ‘tepid’ water to be quite ‘warm’ (or ‘hot’). The other, coming from the physically ,warmer bath will feel that tepid water as ‘cool’ (or ‘cold’). This is taken as a classical case of a sensory illusion, and used to argue that the senses are unreliable, since neither arm can sense the ‘true’ temperature of the common tepid water bath, and taken together, contradict one another. But such conclusions are wholely unwarranted and suffer from all of the errors discussed in this prolegomena.
To understand the situation properly, applying our prolegomena, we must begin by asking ourselves: ‘What does a cool (or warm) sensation correspond to in the physical world?’ Our evidence proves that these sensations do not correspond to the intrinsic or ‘objective’ temperature of the sensed object (in this case the tepid water), but rather to relational properties that exist relative to the water and our separate forearms, each encountering that same water but producing contrasting sensory experiences. One forearm feels ‘cool’ the other forearm ‘warm’. We must then ask the question: ‘What makes all of this consistent and objective relative to our awareness of the external world?’ We must recognize and remind ourselves, that all sense perception is perception of the world (actually our ecological ’embeddedness’ in that world) relative to our internal bodily state, orientation or disposition. We must then ask: ‘What invariant facts explain the seemingly contradictory sensation felt by our two arms?’ Asking the question in this way allows us to interpret the experimental data in the following way: The feeling of cold vs warm correspond to the rate a which our skin is losing or absorbing heat, respectively, relative to the ‘touched’ object’ at that physical point of contact. When the rate of gain or loss of heat goes to zero, we no longer detect the relative temperature of the object (we actually perceive the object as having no temperature). These are the objective facts to which our thermal senses are responding at any given moment. Warmth and cold (qua sensations) correspond to the contrasting rates at which our body, at the point of physical contact with the external object, are gaining or losing heat. You may ask: ‘But if our sensations are to be objective, and give us true knowledge of things in themselves, how do the senses detect the absolute, ‘true’, objective (intrinsic) properties (in this case temperature) of an external object?’ The answer is: Our senses do not and cannot detect the absolute properties of sensed objects. Nor does objectivity of perception require that they do. Furthermore, the inability of our senses to detect the absolute properties of ambient energy is not a form of cognitive failure, it is merely a fact about how (in the case in point) the thermal properties of the external world are detected by the thermal sensors of our sensory system. From the perspective of cognitive function and it integrative nature, it is not the purpose of our sensory systems to perceive or identify ‘the thing in itself’, i.e., the intrinsic, context-free consciousness-independent properties of objects. Perceptions are detected relational facts about our environment, about the relationships of properties of objects relative to our own ecological context (our being in the world).
To deny that perception, which is the grasp of relationships and not of absolutes, constitutes real knowledge of external objects and our relationship to them, is the basis of the Kantian fallacy of the dichotomy of the phenomenal vs the noumenal world, which leads to the misguided concept of ‘das Ding an sich‘ (the thing in itself), which according to Kant, can never be perceived, or known for it exists only as an intuitive abstraction whose being as such is unreachable by our senses. For perception (a conscious experience resulting from the detection of objects in one’s world and their relationship to oneself) to exist in some form (determined by the ontological nature of the perceiver and the perceiving apparatus), is argued by Kant as proof that perception is not ‘true’ knowledge, which must exist (apparently) in no form but must be some kind of direct apprehension of reality achieved by no sensory means. True perception must not involve the structuring of sensory content. But such structuring is, according to Kant, necessary to and definitive of man’s method of perception. To be true perception, it must grasp things in themselves, independent of the perceiver in any way. Thus to perceive objects as relational facts about the world relative to the perceiver, is necessary to human perception, but make impossible true perception of things in themselves. In his Critique of Pure Reason, Kant writes:
Things as they are “in themselves” — the thing in itself or das Ding an sich — are unknowable. For something to become an object of knowledge, it must be experienced, and experience is structured by the mind—both space and time being the forms of intuition, “Anschauung” in German, (for Kant, intuition is the process of sensing or the act of having a sensation) or perception, and the unifying, structuring activity of concepts. These aspects of mind turn things-in-themselves into the world of experience. There is never passive observation or knowledge. – from the Wikipedia discussion of Kant’s Critique of Pure Reason,
This is the denial of the validity and objectivity of all perceptual knowledge (and since all conceptual knowledge rests on perceptual knowledge) it is the rejection of all knowledge as such. Ayn Rand argues that Kant’s deepest fallacy is his argument that consciousness cannot know reality because any form of consciousness possesses a specific identity and that identity is, qua identity, a subjective block to objective knowledge. Ayn Rand’s succinct and pointed response to Kant is this:
Even apart from the fact that Kant’s theory of the “categories” as the source of man’s concepts was a preposterous invention, his argument amounted to a negation, not only of man’s consciousness, but of any consciousness, of consciousness as such. His argument, in essence, ran as follows: man is limitedto a consciousness of a specific nature, which perceives by specific means and no others, therefore, his consciousness is not valid; man is blind, because he has eyes—deaf, because he has ears—deluded, because he has a mind—and the things he perceives do not exist, because he perceives them. – Ayn Rand, For the New Intellectual: The Philosophy of Ayn Rand, Random House, New York, 1961, pages 32-33.
The entire apparatus of Kant’s system, like a hippopotamus engaged in belly-dancing, goes through its gyrations while resting on a single point: that man’s knowledge is not valid because his consciousness possesses identity. – Ayn Rand, Introduction to Objectivist Epistemology, The Objectivist, New York, 1967, p. 71.
Such is the epistemological consequence of imposing a priori criteria on what one will regard as ‘true’ knowledge. It as a form of anti-science and ex-cathedra pronouncements of what knowledge is before examining the process and nature of cognition itself. It is a deliberate (rationalistic) disregard of what cognition, in this case perception of the world, must consist of: a consciously achieve awareness as the product of a complex causal chain involving physical, biological, physiological, conscious, causal mechanisms. It is exactly this causal complex that is addressed by my 1975 thesis. My thesis is not, nor does it attempt to be, a proof of the validity of the senses. For that is a philosophical/epistemological position that must be grasped before engaging in any attempt to acquire knowledge or proof of any objective phenomena. My thesis merely attempts to explain how our senses achieve objective perception of the world.
Later in this thesis, we will learn about why the absolute detection of external energy magnitudes must be omitted by our senses, if they are to function properly (and even survive), and how the senses are far more ‘interested’ in (i.e., reactive to) invariants in contrasting ratios of dynamic (behaviorally induced changing) energy gradients across energy ‘boundaries’ and how the detection of these complex facts (experienced as ‘simple’ sensory facts) are necessary for the achievement of objective, direct awareness of the external world. The explication of this seemingly astonishing hypothesis, the essential Gibsonian perspective, is fully elaborated by our thesis.
Consider this thesis an homage to James J. Gibson for his seminal opus, The Senses Considered as Perceptual Systems (Houghton Mifflin Company, Boston, 1966) and his final opus, The Ecological Approach to Visual Perception (Houghton Mifflin Company, Boston, 1979)m and to his wife and colleague, Eleanor J. Gibson for her profound work on perceptual learning: Principles of Perceptual Learning and Development (Appleton-Century-Crofts, Meredith Corporation, New York 1969). I must also mention Edward S. Reed’s excellent chronicle of Gibson’s scientific career and intellectual development: James J. Gibson and the Psychology of Perception (Yale University Press, New Haven, 1988). Note: Only the first (The Senses Considered) of these four books was published before I wrote my 1975 thesis. If the last three of the books had been available, my thesis would have been all the more enriched by my diligent integration of their contents. I hope that you are sufficiently intrigued to read the full thesis before drawing your own conclusions, or, to paraphrase Gibson ‘Looking for yourself.’
A discussion about this paper can be found on facebook here: http://on.fb.me/1gDLL9o
Published on: Mar 15, 2014 @ 22:02
Latest page revision: July 4, 2018 @ 10:58 pm