Keith Allen

Colours appear to instantiate a number of structural properties: for instance, they stand in distinctive relations of similarity and difference, and admit of a fundamental distinction into unique and binary. Accounting for these structural properties is often taken to present a serious problem for physicalist theories of colour. This paper argues that a prominent attempt by Byrne and Hilbert to account for the structural properties of the colours, consistent with the claim that colours are types of surface spectral reflectance, is unsuccessful. Instead, it is suggested that a better account of the structural properties of the colours is provided by a form of non-reductive physicalism about colour: a naïve realist theory of colour, according to which colours are superficial mind-independent properties.

Locke Defines Knowledge at the beginning of Book IV of the Essay concerning Human Understanding as “the perception of the connexion and agreement, or disagreement and repugnancy of any of our Ideas” (E IV.i.2).1 So defined, knowledge varies along two dimensions. On the one hand, there are four “sorts” of knowledge: of identity or diversity; relation; co-existence or necessary connection; and real existence. On the other hand, there are three “degrees” of knowledge: intuitive knowledge, which consists in the “immediate” perception of agreement or disagreement between ideas (E IV.ii.1); demonstrative knowledge, which consists in the perception of agreement or disagreement by way of intermediate (or intervening)..

This paper presents an ‘over-representational’ account of blurred visual experiences. The basic idea is that blurred experiences provide too much, inconsistent, information about objects’ spatial boundaries, by representing them as simultaneously located at multiple locations. This account attempts to avoid problems with alternative accounts of blurred experience, according to which blur is a property of a visual field, a way of perceiving, a form of mis-representation, and a form of under-representation.

Objects appear different as the illumination under which they are perceived varies. This fact is sometimes thought to pose a problem for the view that colours are mind-independent properties: if a coloured object appears different under different illuminations, then under which illumination does the object appear the colour it really is? I argue that given the nature of natural daylight, and certain plausible assumptions about the nature of the colours it illuminates, there is a non-arbitrary reason to suppose that it is under natural daylight that we are able to perceive the real colours of objects.

Jonathan Cohen has produced a powerful argument for Colour Relationalism: the metaphysical thesis that colours are relational properties of a certain sort—relational with respect to perceivers and circumstances. Cohen makes two important assumptions: one is that Colour Relationalism and Colour Irrealism (which include Colour Eliminativism, Fictionalism and other “error theories”) are rivals; the second is that “error theories” are theories of last resort. In this paper, I challenge both assumptions. In particular, I argue that there is good reason to think that Colour Relationalism needs to be supplemented by some version ofan Error theory. In so doing, I examine, in detail, the issues raised in a paper by Janet Levin in which she engages in an instructive debate with Colin McGinn. Levin’s paper is important since Cohen places heavy reliance on her arguments, both in defending his relationalist theory against crucial objections, and in his dismissal of error theories.