Qualia Change and Colour Science

Philosophy and Phenomenological Research, 2013

Color qualia inversion scenarios have played a key role in various philosophical debates. Most notably perhaps, they have figured in skeptical arguments for the fundamental unknowability of other persons' color experiences. For these arguments to succeed, it must be assumed that a person's having inverted color qualia may go forever unnoticed. This assumption is now generally deemed to be implausible. The present paper defines a variant of color qualia inversion-termed ''color qualia compression''-and argues that the possibility of undetectable color qualia compression is immune to the objections that have been levelled against color qualia inversion arguments, and that color qualia compression scenarios support full-blown skepticism regarding other people's color experiences. 2 See, for instance, , , , . 3 In fact, if our skeptical claim is correct, then color qualia compression scenarios can quite generally serve all dialectical purposes that color qualia inversion scenarios were meant to serve. This can be readily seen from Byrne's [2010, Sect. 3.10] summary of the various requirements that color qualia inversion scenarios are to meet if they are to support the various positions they have been alleged to support.

Consciousness and Cognition, 1999

"Martine Nida-Ru¨melin (1996) argues that color science indicates that behaviorally undetectable spectrum inversion is possible and raises this possibility as an objection to functionalist accounts of visual states of color. I show that her argument does not rest solely on color science, but also on a philosophically controversial assumption, namely, that visual states of color supervene on physiological states. However, this assumption, on the part of philosophers or vision scientists, has the effect of simply ruling out certain versions of functionalism. While Nida-Ru¨melin is quite right to search for empirical tests for claims about the nature of visual states, philosophical issues remain pivotal in determining the correctness of these claims."

Skusevich and P. Matikas (eds), Color Perception: Physiology, Processes and Analysis, chap. 6, Nova Science Publishers, 2009

Most philosophical or scientific theories suppose that colour composition judgments refer to the way colours appear to us. The dominant view is therefore phenomenalist in the sense that colour composition is phenomenally given to perceivers. This paper argues that there is no evidence for a phenomenalist view of colour composition and that a conventionalist approach should be favoured.

Consciousness and Cognition, 1999

Commentary on P. W. Ross (1999). Color science and spectrum inversion: A reply to Nida-Rümelin. Consciousness and Cognition, 8, 566-570. 1 More precisely my aim was to show that certain versions of functionalism violate the prima facie constraint cited in Ross's paper. But, for simplicity, it will be sufficient to think of a conflict in the sense of logical incompatability. The argument can also be formulated in this way if one restricts the attack to those versions of functionalism that deny that pseudonormal people would be red-green inverted (the externalist versions of functionalism Ross has in mind are an example thereof). Contrary to this, the accepted theory about the physiological basis of color vision implies that they would be red-green inverted. (For this way to put the point see my more recent paper (Nida-Rümelin, 1999).

Behavioral and Brain Sciences, 1999

The Philosophical Quarterly, 2006

A dual referent approach to colour theory maintains that colour names have two intended, equally legitimate referents. For example, one might argue that 'red' refers both to red appearances or qualia, and also to the way red objects reflect light, the spectral surface reflectance properties of red things. I argue that normal cases of perceptual relativity can be used to support a dual referent approach, yielding an understanding of colour whose natural extension includes abnormal cases of perceptual relativity. This contrasts with Peacocke's multi-referent view, according to which such abnormal cases force us to introduce a wholly distinct kind of colour experience. I also argue that the two uses of colour names, arising from their two referents, have different extensions, even in normal perceptual circumstances, a consequence which conflicts with the heart of Rosenthal's dual referent view.

Stance: An International Undergraduate Philosophy Journal, 2019

For A. J. Ayer, the occurrence of delusions confutes the notion that we perceive the world directly. He argues instead that perceptions are caused by immaterial "sense data" which somehow represent the properties of material things to us in our experiences. J. L. Austin systematically rejects Ayer's claims, arguing that the occurrence of delusions does not preclude the possibility of direct perception, and that, indeed, our normal perception is direct. I challenge both philosophers' ideas by examining how they deal with the phenomenon of colour.

Physicalism about colour is the thesis that colours are identical with response-independent, physical properties of objects. I endorse the Argument from Structure against Physicalism about colour. The argument states that Physicalism cannot accommodate certain obvious facts about colour structure: for instance, that red is a unitary colour while purple is a binary colour, and that blue resembles purple more than green. I provide a detailed formulation of the argument. According to the most popular response to the argument, the Physicalist can accommodate colour structure by explaining it in terms of colour experience. I argue that this response fails. Along the way, I examine other interesting issues in the philosophy of colour and colour perception, for instance the relational structure of colour experience and the description theory of how colour names refer.

Color relationalism, ordinary illusion, and color incompatibility

Relationalism is a view popularized by Cohen according to which the colors are relational properties. Cohen’s view has the unintuitive consequence that the following propositions are false: (i) no object can be more than one determinate or determinable color all over at the same time; (ii) ordinary illusion cases occur whenever the color perceptually represented conflicts, according to (i) above, with the object’s real color; and (iii) the colors we perceive obey (i). I investigate Cohen’s attempt to address these intuitive propositions with which his view struggles and find it to be incompatible with how he motivates his view.