William A. Sharp

Three popular objections to reductionism about color, experience as of impossible colors, the unary/binary distinction, and structural mismatch, are issues just, I argue, for the (probably default) version of reductionism according to which colors reduce to sets of surface spectral reflectances. They are not problems for the version on which colors are dispositions to reflect coarse-grained intensities of light are—what in colorimetry are called “object colors.” This article sets out to demonstrate the virtues of the latter reductionism.

Relationalism about colour (as described in Cohen’s 2004 article on colour properties and his 2009 book The Red and the Real) is motivated by the thought that by identifying colours with relations between objects, subjects and viewing circumstances we can provide the best realist, general, ecumenical accommodation of perceptual variation data. This ‘best’-claim is supported by the charge that one of the view’s ecumenical rivals does uniquely badly in respect of fit with mainstream psychosemantics. This case for relationalism is complicated by Cohen’s later acknowledgement that relationalism has psychosemantic ills of its own. In this paper I argue that Cohen’s proposed remedying of those ills fails.

Yablo has argued (1995) the received view in philosophy, that spectral surface reflectances (SSRs) are the causes of color-experience, is mistaken. SSRs, he says, are not commensurate with our experiences and so are not their causes. This motivated Yablo to posit sui generis, “unscientific” color properties to fill the resultant causal lacunae (cf. Watkins in Australasian Journal of Philosophy 83:33–52, 2005;Watkins in Philosophical Studies 150:123–137, 2010; Gert, in: Brown & Macpherson (eds) Routledge Handbook of Philosophy of Colour, Routledge, 2021). This move, I argue, only works if no physical posits commensurate with our experiences exist to fill the same lacunae. And there are, today, familiar such posits: dispositions to reflect long-, medium-, and short-wavelength light (Bradley & Tye in Journal of Philosophy 98:469, 2001; cf. Koenderink in Color for the Sciences, MIT Press, 2010). Moreover, these dispositions are commensurate with our cone and opponent-neural states too, those states, more than our color-experiences, demanding paradigmatically physical causes. The above, conjoined with the platitude that colors are the causes of color-experience, motivates reducing colors to the noted (physical) dispositions.

Naïve realists have yet to successfully discharge the problem of supersaturated hue, afterimage-experiences as of hued surfaces that are beyond-maximally saturated. The experiences are a problem for the view because supersaturation, qua property of external objects, is an impossible color property. Accordingly, the experiences cannot be handled in terms of their indiscriminability from perceptions of such surfaces, in the manner of Martin ( 2004 ). Nor can they be handled in terms of seen surfaces looking supersaturated, in the manner of Kalderon ( 2011 ). This ramifies for every naïve realist view which grounds perceptual phenomenology in relation to perceptions, or to the qualities perceptions reveal.

Representationalism is today the leading physicalist theory of the phenomenal character of perceptual experience. And Russellian representationalism, which identifies contents with extensions, is the leading iteration of that theory. If there exist phenomenally distinct experiences as of the impossible, then these would _prima facie_ serve as counterexamples to the theory. In order that they definitively serve as counterexamples, it needs to be that there is no plausible account of the experiences on which they decompose into constituent elements each of which is unproblematic from the perspective of the theory. The contention of this paper is that the _stygian color experiences_, afterimage-experiences as of maximally dark, hued surfaces, of Churchland (Churchland, Philosophical Psychology 18:527–560, 2005) serve as counterexamples to Russellian representationalism.