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.

This paper sketches a phenomenological analysis of visual mental imagery and uses it to criticize representationalism and the internalist-versus-externalist framework for understanding consciousness. Contrary to internalist views of mental imagery imagery experience is not the experience of a phenomenal mental picture inspected by the mind’s eye, but rather the mental simulation of perceptual experience. Furthermore, there are experiential differences in perceiving and imagining that are not differences in the properties represented by these experiences. Therefore, externalist representationalism, which maintains that the properties of experience are the external properties represented by experience, is an inadequate account of conscious experience

This paper develops a bridge from AL issues about the symbol–matter relation to AI issues about symbol-grounding by focusing on the concepts of formality and syntactic interpretability. Using the DNA triplet-amino acid specification relation as a paradigm, it is argued that syntactic properties can be grounded as high-level features of the non-syntactic interactions in a physical dynamical system. This argu- ment provides the basis for a rebuttal of John Searle’s recent assertion that syntax is observer-relative (1990, 1992). But the argument as developed also challenges the classic symbol-processing theory of mind against which Searle is arguing, as well as the strong AL thesis that life is realizable in a purely computational medium. Finally, it provides a new line of support for the autonomous systems approach in AL and AI (Varela & Bourgine 1992a, 1992b). © 1997 Academic Press

The Cambridge Handbook of Consciousness is the first of its kind in the field, and its appearance marks a unique time in the history of intellectual inquiry on the topic. After decades during which consciousness was considered beyond the scope of legitimate scientific investigation, consciousness re-emerged as a popular focus of research towards the end of the last century, and it has remained so for nearly 20 years. There are now so many different lines of investigation on consciousness that the time has come when the field may finally benefit from a book that pulls them together and, by juxtaposing them, provides a comprehensive survey of this exciting field. An authoritative desk reference , which will also be suitable as an advanced textbook

Could there be genuinely novel colours — that is, visual qualities having a hue that bears a resemblance relation to red, green, yellow, and blue, yet is neither reddish, nor greenish, nor yellowish, nor blueish?1 And if there could be such colours, what would it be like to see them? How would the colours look? In his article,"Epiphenomenal Qualia,"2 Frank Jackson presents a philosophical thought experiment that raises these questions . Jackson asks us to imagine a perceiver named Fred who is like us except that he has the ability to see a hue we cannot see. Jackson's question is: "What is the new colour or colours like?"3 Jackson argues that all the physical information about Fred, including the physiology of his brain and visual system, and his dispositions to behaviour, would not enable us to answer this question. The totality of physical information would still leave out something about Fred's experience, namely, what the extra hue is like from the subjective perspective of Fred. And if at some point we became able to see this extra hue , we would learn something that we did not know as a result of having all the physical information about Fred: We would learn how the extra hue looks and thereby learn just what it was that made Fred's experience different from ours. Jackson calls his argument "the knowledge argument." In his view, the argument is similar to Thomas Nagel's in his article "What is it Like to Be a Bat?,"4 but both its point and ultimate conclusion are different. Nagel argues that facts about what conscious experience is like for some creature are essentially connected to the subjective perspective of the creature. The problem that Nagel poses is, how could such facts be revealed in anything objective and physical about the creature? How could the objective characterization indicate what it is like to be the creature ? The point of Jackson's argument, however, is not that we would not know what it is like to be Fred even if we knew everything physical about him ; it is rather that there is still something we do not know about Fred's experience — a property that it has — even when we have all the physical information about him: We do not know how the extra hue that Fred sees looks to Fred, and so we do not know all that there is to know about how Fred's experience of seeing the extra hue differs from his experience of seeing red, green, yellow, and blue.5 Jackson's conclusion is also stronger than Nagel's.

Contributors to the latest Canadian Journal of Philosophy Supplementary Volume, _The Problem of Consciousness_, make connections regarding what is consciousness and how it is related to the natural world. The essays in this volume address this question from the perspective of phenomenological philosophy of mind, a new trend that integrates phenomenology, analytic philosophy, and cognitive science. The guiding principle of this new thinking is that precise and detailed phenomenological accounts of subjective experience are needed if significant progress is to be made in understanding consciousness and its place in the natural world. From this standpoint, the essays collected here explore a variety of nuances concerning consciousness, including time consciousness, perception, schizophrenia, empathy, and intersubjectivity. Also addressed are fascinating methodological issues about the relationship between phenomenology and other approaches to understanding the mind in science and philosophy