On the Evolution of Conscious Sensation, Conscious Imagination, and Consciousness of Self

Robert G Kunzendorf, Robert Kunzendorf

• Publisher: Routledge
• Year: 2016
• Print ISBN:
  9780895039026
• eBook ISBN:
  9781351864084
• Topic: Philosophy
• Subtopic: Mental Health in Psychology

Philosophical 'thought experiments' invoking inverted spectra, zombies, et cetera suggest that conscious sensations have no function, and psychological studies finding no correlation between vivid visual imaging and visual problem solving suggest that conscious images have no function. Furthermore, both philosophical and psychological theories suggest that self-consciousness has no function. Countering such suggestions, the post-Darwinian double-aspect theory which Professor Robert Kunzendorf's introduces in the first chapter of his monograph On the Evolution of Conscious Sensation, Conscious Imagination, and Consciousness of Self points to evolutionary functions of certain sensations, youngling vivid images, and self-consciousness. Kunzendorf's second chapter presents evidence that the most primitive sensation-pain, the subjective aspect of free nerve endings or nociceptors-has a survival-promoting function. But as the pressure nociceptor mutates into a touch receptor, the heat nociceptor into temperature receptor, and the chemical nociceptor into a taste receptor, the painful qualia of these nociceptors evolve respectively into touch sensation, temperature sensation, or taste sensation-painless sensations that add no survival benefit to their receptor's physical aspect. Building on evidence that retinal receptors embodying visual qualia evolved from primitive eyespots responsive to injurious 'heat at a distance' or painful light, the third chapter presents evidence that visually imagined sensations are the subjective qualities of retinal receptors that are corticofugally innervated in warm-blooded animals-for the developmental purpose of testing cortically hypothesized sensory-motor rules that have greater survival value than cold-blooded stimulus-response associations. The fourth and final chapter focuses on self-conscious reality-testing and on visuo-spatial self-conceptualization, and presents evidence that such manifestations of self-awareness evolve only in those warm-blooded animals whose rule-developing youth lasts two years or longer-that is, those mammals and birds whose survival during the imaginal testing of rules is subjected to prolonged risk if self-consciousness that one is imaging sensations (rather than perceiving sensations) is absent.

CHAPTER 1

Theoretical Background and the Current Evolutionary Hypotheses

There is a sense in which I share the underlying motivation of the reductionists—to see how a unified theory of consciousness and the brain might be logically possible. But whereas they wish essentially to bring the mind within the domain of physical science, I believe that to be impossible; rather, the methods of scientific description, analysis and explanation have to be extended to include the mind…. We should have in mind the ideal of an explanation of consciousness that shows it to be a necessary feature of certain biological systems—an explanation that allows us to see that such systems could not fail to be conscious…. I think it is inevitable that the pursuit of such an account will lead to an alteration of our conception of the physical world.

—“What is the Mind-Body Problem?”
Thomas Nagel (1993, pp. 6–7)

On sunny weekends when my wife and I go out for an afternoon walk, I look up at the sky, experience conscious sensations of blueness, and am self-conscious that I am perceiving the blueness. On dark nights when I dream about blue skies, I also experience conscious sensations of blueness, but throughout my subconsciously imaged dream, I am not self-conscious that I am imaging the blueness. Why do our brains represent sky as bluish sensations instead of reddish sensations or melodious sensations or no sensations at all? Indeed, why have conscious sensations of blueness evolved at all? And why do our brains generate sensations that are accompanied by self-consciousness when we are awake but are unaccompanied by self-consciousness when we are dreaming? That is, why has wakeful self-consciousness evolved?

In developing answers to these questions and related ones, I will be generating and testing evolutionary hypotheses that are derived from the psychophysical theories of the philosopher Gottfried Leibniz, the psychological scientists Gustav Fechner and Oswald Külpe, the clinical psychologist Morton Prince, and the neuropsychologist Charles Sherrington. Testing the axiomatic value of an evolutionary hypothesis or any other hypothesis is practically impossible, of course, as this requires that all alternative hypotheses be proven false. But as a scientist, I am primarily interested in testing the discovery value of hypotheses rather than their axiomatic value. Whereas the scientific theory of evolution has guided physical anthropologists to newly discovered data showing the anatomical relatedness of birds to bird-hipped dinosaurs and the genetic relatedness of human beings to chimpanzees, the religious notions of creationism and “intelligent design”¹* have led us to no such undiscovered truths in anatomical or genetic data. And whereas scientific models of self-consciousness have guided psychologists to newly discovered data showing the relatedness of hallucinated imagination to dissociated perception, the religious notion of a soul has afforded us no such discovery value. Accordingly, this book’s hypotheses regarding conscious sensation, conscious imagination, and self-consciousness are intended to lead us to previously undiscovered truths in new data and to previously undiscovered relationships among old data—truths and relationships that might also be explained by reformulating alternative theses after the fact, but that would never be uncovered by such theses in the first place. Bearing this intention in mind, let us proceed by focusing on the theoretical approaches from which the evolutionary hypotheses in this book are derived.

CONSCIOUS SENSATION: SUBSTANCE DUALISM VERSUS ASPECT DUALISM

Historically, the development of psychological science is rooted in Gottfried Leibniz’s (1765/1896) theoretical challenge to Cartesian dualism. According to René Descartes’ (1641/1988) dualism, a soul-like “subject of consciousness” or nonphysical “homunculus” is conscious of “objects of consciousness,” all of which are physical in substance. For Descartes, even visually imagined “objects of consciousness” are physical in quality, and only “pure understanding” without any sensory qualities is substantively nonphysical.

In the act of understanding the mind turns as it were towards itself, and contemplates one of the ideas contained in itself; in the act of imagining, it turns to the body, and contemplates something in it resembling an idea understood by the mind itself. (p. 36)

The Cartesian assumption that all “objects of consciousness” are physical is naïvely adopted by most practitioners of behavioral science, cognitive science, and neuroscience. In embracing the animal as a physical model of human behavior and eschewing introspective data within the human mind, the behavioral scientist B. F. Skinner (1974) argued that introspective observers of an external object like salt do not really “have a salty taste” but simply “taste salt” (p. 78). And in “consider[ing] events taking place in the private world within the skin,” Skinner argued that “what is felt or introspectively observed is not some nonphysical world of consciousness, mind, or mental life but the observer’s own body” (pp. 16–17). What or who then is the “subject of consciousness” that observes an “object of consciousness” such as salt or the body? In embracing the computer as a physical model of the human mind, the cognitive scientist Bernard Baars (1988) argued that nonconscious representations in the mind’s computer-like memory become “conscious events [which] are objectlike” (p. 187) by “gain[ing] access to the global workspace” or working memory (p. 43). What or who is conscious of the objectlike events in the global workspace? In embracing the physical brain as a third-person starting point for modeling human consciousness, the neuroscientist Daniel Schacter (1989) argued that “for explicit remembering to occur, the output of declarative/episodic memory must be able to gain access to CAS [Conscious Awareness System]” (p. 366) and that “a posterior region of the cortex, critically involving the inferior parietal lobes, constitutes part of [the] system subserving conscious awareness [CAS]” (p. 370). Who or what then is conscious of the memories that “gain access” to the brain’s parietal lobes? To the extent that the behavioral scientist, the cognitive scientist, and the neuroscientists reject the immaterial Cartesian soul, they must suppose that a neural “subject of consciousness” is somehow conscious of physical objects—a question-begging supposition that amounts to “Cartesian materialism” and as such is criticized by Daniel Dennett (1991), Susan Blackmore (2004), and Eugene Brooks (2004–2005).

Deeming it impossible for any physical or nonphysical entity to be conscious of anything outside itself, Gottfried Leibniz (1765/1896) reconceived the soul as a nonphysical “bundle of sensations” paralleling neural events in the brain and representing the physical world outside the brain. Accordingly, the soul is not conscious of any physical objects in the brain or any nonphysical entities in the mind. Rather, the soul is composed of conscious sensations, which, on Leibniz’s account, are nonphysical in substance and are subjectively transformed in parallel with physical transformations in the nervous system. It is important to note that both Leibniz’s psychophysical parallelism and Descartes’ (1641/1988) subject-object metaphysics were conceptualized in the terms of substance dualism, which posits the existence of souls that are nonphysical in substance and objects that are physical in substance. Ultimately, the psychophysicist Gustav Fechner (1860/1966) reinterpreted Leibniz’s psychophysical parallelism in the terms of aspect dualism or double-aspect materialism. Fechner maintained that conscious sensations are the subjective aspects or subjective qualities of particular neural states. Thus, the mind is not conscious of sensations; subjectively, the mind is its sensations, and physically, it is the nervous system with those subjective aspects.

The most compelling example of such a subjective quality or conscious sensation is the visual after-sensation. Certainly, the circular pink after-sensation that remains after staring at a green circle for 2 minutes is neither a pink object in the world outside the body nor an object in the gray matter of the brain, but is the subjectively pinkish quality of particular neurons in a particular state of excitation. Furthermore, Fechner (1860/1966) was correct to assume that after-sensations of this sort do not differ qualitatively from subjectively similar sensations that are immediately perceived, given Kunzendorf, Thompson, and Butler’s (1995–1996) demonstration that the pink after-sensation following a green percept and the pink sensation in a pink percept are not distinguishable under experimentally controlled conditions.

Historically, the above-described movement away from Descartes’ (1641/1988) subject/object dualism and toward Fechner’s (1860/1966) psychohysical parallelism made psychological science possible. Cartesian dualism presupposed that physical “objects of consciousness” can be scientifically measured and studied, but that the immaterial and unextended “subject of consciousness” constituting the mind cannot. In contrast, Leibniz’s (1765/1896) psychophysical parallelism implied that the “bundle of sensations” comprising the mind can be introspectively described. Plus, Fechner’s psychophysics demonstrated that the subjective brightness of a visual sensation can be logarithmically related to the physical intensity of light stimulating that sensation, if the light’s changing intensity is recorded every time the sensation becomes twice as bright or half as bright. Co-founding psychological science on Leibniz’s and Fechner’s groundwork, Wilhelm Wundt (1863/1894) introspectively described the mind’s “bundle of sensations,” and William James (1890) insightfully described the mind’s “stream of consciousness.” Neither Wundt nor James deemed it necessary to describe parallel brain events, given that one’s knowledge of all physical events must be mediated by one’s conscious sensations representing those events. Like Leibniz, Wundt advocated substance dualism and equated the soul with the “bundle of sensations” paralleling the brain. In contrast, James (1890, Vol. 1, p. 182) advocated “empirical parallelism” and argued that psychological scientists could and should ignore the metaphysical question of whether the mind’s sensations constitute subjective aspects of the brain, as Fechner argued, or an immaterial substance paralleling the brain, as Leibniz argued.

The metaphysical question raised by Leibniz (1765/1896) and Fechner (1860/1966) was not ignored by 20th century philosophers, however. Mind-brain identity theorists like Herbert Feigl (1958), Stephen Pepper (1960), and John J. C. Smart (1959) asserted that the mind and the brain constitute a single physical entity that doesn’t possess any nonphysical subjective qualities, but that presents as conscious sensations from a subjective or first-person perspective and as neural states from an objective or third-person perspective. By implication, then, it should be possible to predict this physical entity’s objectively observable behaviors from its objectively knowable brain dynamics, without paying any attention to its corresponding sensations. It should be possible, in other words, to replace psychological science with behavioral neuroscience. Countering these reductionist implications of identity theory, the double-aspect materialist Thomas Nagel (1974) argued that the bat’s sensations, whatever they may be like, cannot be reduced to or known from third-person observations of bat echolocation but can only be known as the subjective aspects of being a bat. And further countering the epiphenomenalist implications of any mind-to-brain reduction, Nagel (1993) argued that one reason why the brain’s subjective aspects cannot be reduced to its physical aspects is because some of those subjective aspects can have causal effects on the brain’s physical dynamics.

CURRENT HYPOTHESIS REGARDING THE EVOLUTION OF CONSCIOUS SENSATION

Following the lead of Nagel’s (1993) aspect dualism, Chapter 2 explores the hypothesis that the painful subjective quality of the harm-sensing nociceptor was the first sensation to be naturally selected and that sensations of pain evolved into a variety of sensory qualities paralleling the variety of sensory transmitters that evolved from nociceptors. The nociceptor has the primitive physical quality of a free nerve ending, and its subjective quality of pain has the causal effect of reinforcing trial-and-error behaviors that promote damage-avoidance, healing, and hence, survival. Moreover, there are three variations of the nociceptor. The heat nociceptor, the pressure nociceptor, and the chemical nociceptor are innervated, respectively, by harmful heat, by harmful pressure, and by harmful chemicals. The evolutionary hypothesis to be developed and defended is: (a) that some heat nociceptors evolved into pain-free heat or temperature receptors paralleled by sensations of temperature, others into airborne/waterborne-heat or light receptors paralleled by visual sensations; (b) that some pressure nociceptors evolved into pain-free pressure or touch receptors paralleled by sensations of touch, others into airborne/waterborne-pressure or sound receptors paralleled by auditory sensations; and (c) that some chemical nociceptors evolved into pain-free chemical or taste receptors paralleled by sensations of taste, and others into airborne/waterborne-chemical or smell receptors paralleled by olfactory sensations. “The retina is thus a group of glorified ‘warm-spots,’ the cochlea a group of glorified ‘touch-spots,’” as Sir Charles Sherrington (1911, p. 324) pointed out. But notably, as the sensations paralleling thermal, visual, tactile, auditory, gustatory, and olfactory receptors have evolved from the painful sensation paralleling a particular type of nociceptor, they have not retained the reinforcing quality or the survival value or the usefulness of the nociceptor’s subjective quality of pain. As Susan Blackmore (2004) notes in her book’s chapter on the Evolution of Consciousness, “Some useless traits survive because they are by-products of other traits that have been selected” (p. 146). And compared to pain, sensations of greenness and redness and saltiness and sourness are subjectively useless.

Some of the supporting evidence reviewed in Chapter 2 shows that simple mutations can transform a chemical nociceptor into a taste receptor, a pressure nociceptor into a touch receptor, and a heat nociceptor into a temperature receptor. Other supporting evidence shows that the first primitive eye to evolve—the eyespot of the flatworm—functioned like an airborne heat nociceptor, not like an avian or mammalian eye capable of seeing visual structure. Chapter 2 concludes by considering evidence that the central nervous system (CNS) serves, physically, to process neural signals emanating from sensory transmitters and, subjectively, to generate “tacit knowledge” (Fodor, 1968) in relation to the transmitters’ conscious sensations.

CONSCIOUS IMAGINATION: IMAGISTIC THOUGHTS VERSUS IMAGES CONSTRUCTED FROM IMAGELESS IDEAS

Historically, the psychological study of conscious imagination has been at the crossroads of different approaches to the relationship between the mental and the physical. Psychology’s German co-founder Wilhelm Wundt (1863/1894) and his British student Edward Titchener (1909) deemed it scientifically sufficient to introspectively study one’s own sensations, which can be consciously and directly experienced as such. For the purpose of describing and understanding one’s own thoughts, therefore, they deemed it sufficient to study the “centrally excited sensations” or mental images, which, in their own experience, composed all thoughts. Furthermore, based on introspective comparisons of vivid images with similar percepts, Wundt and Titchener argued that imaged sensations and perceived sensations were not qualitatively different, as Danish psychologist Harold Høffding (1891/1896) also argued:

How does the free flow of ideas come to be recognized by consciousness as distinct from the actual percepts? There is, indeed, as a rule a difference in the degree of strength of a memory-image and a percept; but this difference may be very small, and may even quite disappear…. No grounds are present for arranging the content of consciousness in two different spheres, in the world of possibility and imagination on one hand, and the world of reality and perception on the other. On the contrary, this contrast is discovered only through experiences in great measure bitter. We must often run our head against reality, before it becomes clear to us where its limits lie. (pp. 130–131)

Contrary to such argumentation, however, Kunzendorf (1980, 1985–1986a, 2000) has repeatedly found that sensations with a perceptual source are normally distinguished more quickly from equally vivid sensations of imaginal origin than from fainter sensations of imaginal origin. And based on such findings, Kunzendorf (1987–1988) has theorized tha...

Table of contents

• Cover
• Title Page
• Copyright Page
• Dedication
• Table of Contents
• Preface In Pursuit of Consciousness
• Chapter 1 Theoretical Background and the Current Evolutionary Hypotheses
• Chapter 2 The Evolution of Conscious Sensation
• Chapter 3 The Evolution of Conscious Imagination
• Chapter 4 The Evolution of Consciousness of Self
• Appendix A Introspective Exercise Demonstrating Binocular Illusion of Fused Sensations
• Appendix B On the Role of Pain in Basic Negative Emotions
• Endnotes
• References
• Index