Evan Thompson

In this thesis, I show how decisions about the ontology of colour depend upon the empirical and conceptual relations among levels of explanation for vision. In Chapter 1, I show how the "received" Lockean view of colour is linked to Newton's theory of light and colour. In Chapter 2, I review extensively recent biological, psychophysical, and computational models of colour vision, and I discuss their relations. I also show how the ontological status of colour is linked to these levels of explanation for the specific case of colour constancy. This empirical discussion provides the foundation for Chapters 3 and 4 where I argue that both objectivism and subjectivism are untenable on extensive empirical grounds. ;In Chapter 3, I argue that the computational level of explanation is not sufficient to ground an objectivist view of colour. Colour cannot be identified with surface spectral reflectance, nor can our present conception of colour be replaced by a new concept of physical colour as surface reflectance. An adequate account of colour must, then, be experientialist. I conclude this chapter by showing how arguments against objectivism are not sufficient to establish subjectivism. ;In Chapter 4, I present a novel philosophical argument based on the comparative study of colour vision in different species. This body of research has been largely neglected both by philosophers and by those who work on computational colour vision. My "comparative argument" purports to show that an adequate account of colour must be both experientialist and ecological. Whereas computational objectivism runs afoul of the experiential nature of colour, neurophysiological subjectivism runs afoul of the ecological nature of colour experience. In contrast to both objectivism and subjectivism, I defend a new view of colour, which I call ecological experientialism. According to this view, colour corresponds to a type of property that is interactional, i.e., to a type of property that results from the biological and ecological interactions of perceiving and cognizing animals. Therefore, to account for colour we must state generalizations over the ecologically embodied visual experiences of perceiving animals.

Buddhism originated and developed in an Indian cultural context that featured many first-person practices for producing and exploring states of consciousness through the systematic training of attention. In contrast, the dominant methods of investigating the mind in Western cognitive science have emphasized third-person observation of the brain and behavior. In this chapter, we explore how these two different projects might prove mutually beneficial. We lay the groundwork for a cross-cultural cognitive science by using one traditional Buddhist model of the mind – that of the five aggregates – as a lens for examining contemporary cognitive science conceptions of consciousness.

• An adequate conceptual framework is still needed to account for phenomena that (i) have a first-person, subjective-experiential or phenomenal character; (ii) are (usually) reportable and describable (in humans); and (iii) are neurobiologically realized.2 • The conscious subject plays an unavoidable epistemological role in characterizing the explanadum of consciousness through first-person descriptive reports. The experimentalist is then able to link first-person data and third-person data. Yet the generation of first-person data raises difficult epistemological issues about the relation of second-order awareness or meta-awareness to first-order experience (e.g.

Suppose that a team of neurosurgeons and bioengineers were able to remove your brain from your body, suspend it in a life-sustaining vat of liquid nutrients, and connect its neurons and nerve terminals by wires to a supercomputer that would stimulate it with electrical impulses exactly like those it normally receives when embodied. According to this brain-in-a-vat thought experiment, your envatted brain and your embodied brain would have subjectively indistinguishable mental lives. For all you know—so one argument goes—you could be such a brain in a vat right now.1 Daniel Dennett calls this sort of philosophical thought experiment an “intuition pump” (Dennett 1995). An intuition pump is designed to elicit certain intuitive convictions, but is not itself a proper argument: “intuition pumps are fine if they’re used correctly, but they can also be misused. They’re not arguments, they’re stories. Instead of having a conclusion, they pump an intuition. They get you to say ‘Aha! Oh, I get it!’ (Dennett 1995, p. 182). Philosophers have used the brain-in-a-vat story mainly to raise the problem of radical skepticism and to elicit various intuitions about meaning and knowledge (Putnam 1981). The basic intuition the story tries to pump is that the envatted brain, though fully conscious, has systematically false beliefs about the world, including itself. Some philosophers reject this intuition. They propose that the envatted brain’s beliefs are really about its artificial environment or that it..

We argue that the minimal biological requirements for consciousness include a living body, not just neuronal processes in the skull. Our argument proceeds by reconsidering the brain-in-a-vat thought experiment. Careful examination of this thought experiment indicates that the null hypothesis is that any adequately functional “vat” would be a surrogate body, that is, that the so-called vat would be no vat at all, but rather an embodied agent in the world. Thus, what the thought experiment actually shows is that the brain and body are so deeply entangled, structurally and dynamically, that they are explanatorily inseparable. Such entanglement implies that we cannot understand consciousness by considering only the activity of neurons apart from the body, and hence we have good explanatory grounds for supposing that the minimal realizing system for consciousness includes the body and not just the brain. In this way, we put the brain-in-a-vat thought experiment to a new use, one that supports the “enactive” view that consciousness is a life-regulation process of the whole organism interacting with its environment.

In the past decade, the notion of a neural correlate of consciousness (or NCC) has become a focal point for scientific research on consciousness (Metzinger, 2000a). A growing number of investigators believe that the first step toward a science of consciousness is to discover the neural correlates of consciousness. Indeed, Francis Crick has gone so far as to proclaim that ‘we … need to discover the neural correlates of consciousness.… For this task the primate visual system seems especially attractive.… No longer need one spend time attempting … to endure the tedium of philosophers perpetually disagreeing with each other. Con- sciousness is now largely a scientific problem’ (Crick, 1996, p. 486).2 Yet the question of what it means to be a neural correlate of consciousness is actually far from straightforward, for it involves fundamental empirical, methodological, and _philosophical _issues about the nature of consciousness and its relationship to the brain. Even if one assumes, as we do, that states of consciousness causally depend on states of the brain, one can nevertheless wonder in what sense there is, or could be, such a thing as a neural correlate of consciousness.

For many years emotion theory has been characterized by a dichotomy between the head and the body. In the golden years of cognitivism, during the nineteen-sixties and seventies, emotion theory focused on the cognitive antecedents of emotion, the so-called “appraisal processes.” Bodily events were seen largely as byproducts of cognition, and as too unspecific to contribute to the variety of emotion experience. Cognition was conceptualized as an abstract, intellectual, “heady” process separate from bodily events. Although current emotion theory has moved beyond this disembodied stance by conceiving of emotions as involving both cognitive processes (perception, attention, and evaluation) and bodily events (arousal, behavior, and facial expressions), the legacy of cognitivism persists in the tendency to treat cognitive and bodily events as separate constituents of emotion. Thus the cognitive aspects of emotion are supposedly distinct and separate from the bodily ones. This separation indicates that cognitivism’s disembodied conception of cognition continues to shape the way emotion theorists conceptualize emotion.

Colour fascinates all of us, and scientists and philosophers have sought to understand the true nature of colour vision for many years. In recent times, investigations into colour vision have been one of the main success stories of cognitive science, for each discipline within the field - neuroscience, psychology, linguistics, computer science and artificial intelligence, and philosophy - has contributed significantly to our understanding of colour. Evan Thompson's book is a major contribution to this interdisciplinary project. Colour Vision provides an accessible review of the current scientific and philosophical discussions of colour vision. Thompson steers a course between the subjective and objective positions on colour, arguing for a relational account. This account develops a novel `ecological' approach to colour vision in cognitive science and the philosophy of perception. It is vital reading for all cognitive scientists and philosophers whose interests touch upon this central area

The following points are discussed in response to the commentaries: (1) A taxonomy of perceptual completion phenomena should rely on both phenomenological and mechanistic criteria. (2) Certain forms of perceptual completion are caused by topographically organized neural processes the view that there must be a pictorial or spatial neural-perceptual isomorphism at the bridge locus – should be rejected. Although more abstract kinds of isomorphism are central to the neural-perceptual mapping, the perceptual cannot be exhaustively explained in terms of the neural, and therefore the explanation of perception cannot be reduced to uncovering neural-perceptual isomorphisms. (5) The task of vision is to guide action in the world, not to construct a detailed world-model in the head. (6) Neural filling-in facilitates the integration of information and thereby helps the animal find out about its environment. (7) Perceptual content needs to be understood at the level of the person or animal interacting in the world

This article argues against the no-self or nonegological account of bodily self-awareness. It proposes an account of consciousness that challenges Miri Albahari's forceful defence of a nonegological view of consciousness, particularly its sharp distinction between subject and self. It contends that the subject of experience is a bodily subject and not merely an embodied one and argues that in order to be a subject of experience even in the minimal sense of witnessing-from-a-perspective, one must be prereflectively aware of oneself as a living body. It also argues in defence of the necessary presence of a minimal bodily sense of self as a constitutive feature of perspectival awareness of the world.

Let me begin by thanking my commentators for taking the time to read my book and to write such constructive commentaries. I would also like to thank Christian Coseru for organizing and chairing the panel at the International Society for Buddhist Philosophy at the 2015 meeting of the Pacific Division of the American Philosophical Association, at which three of the commentaries were originally presented together with my response. Finally, I am grateful to Philosophy East and West for publishing this exchange. Philosophy East and West published my first academic paper, so I am especially happy to have this exchange appear here.1In what follows, I have arranged my response according to the topics and issues raised by...