John O'Dea

Perceptual constancy, often defined as the perception of stable features under changing conditions, goes hand in hand with variation in how things look. A white wall in the orange afternoon sun still looks white, though its whiteness looks different compared with the same wall in the noon sun. Historically, this variation has often been explained in terms of our experience of “merely sensory” or subjective properties – an approach at odds with the fact that the variation does track objective features of the perceptual situation, such as illumination. One approach, becoming more common, is to account for the variation in terms of further “dimensions” to perceptual experience. Especially in colour perception, this is a natural thought to have but the idea is often left vague. In this paper I argue that the “dimensional” strategy has problems of its own, but is useful in drawing out some interesting complications in the way perceptual experience is structured. Specifically, the structure of “constancy spaces” brings out the different ways in which there is stability and instability in the experience of constancy, without the need for novel or merely subjective features. Instability arises in a contingent structural feature of perceptual experience.

Higher-order theories of consciousness, such as those of Armstrong, Rosenthal and Lycan, typically distinguish sharply between consciousness and phenomenal character, or qualia. The higher-order states posited by these theories are intended only as explanations of consciousness, and not of qualia. In this paper I argue that the positing of higher-order perceptions may help to explain qualia. If we are realists about qualia, conceived as those intrinsic properties of our experience of which we are introspectibly aware, then higher-order perception might have an explanatory role as the means by which we are aware of these properties. This would also allow us to treat qualia as the inner appearances resulting from inner perceptions, and therefore to treat them as intentional objects

Stephen Kershnar (2004) recently argues that under its most plausible interpretation, equality of opportunity is simply not something worth pursuing; at least, not for itself. In this paper I try to show that even if we accept Kershnar's characterisation of equality of opportunity in terms of weighted aggregate chances, none of his objections succeed. Opportunities, not outcomes, are the appropriate focus of EO advocates; hedonic treadmills are irrelevant to the issue; we do not need to assume general equality in some attribute to ground equality of opportunity; finally, it is possible to show that it is permissible to promote EO at some cost to other independent values

If we assume that the operation of each sense modality constitutes a different experience – a visual experience, an auditory experience, etc – we are faced with the problem of how those distinct experiences come together to form a unified perceptual encounter with the world. Michael Tye has recently argued that the best way to get around this problem is to deny altogether that there are such things as purely visual (and so forth) experiences. Here I aim to show not simply that Tye’s proposed solution fails, but that its failure is highly instructive because it allows us to see that the transparency thesis, which lies at the heart of the case against qualia, and of most representationalist theories of experience, is more problematic than is often supposed.

I defend a solution to a long-standing problem with perceptual appearances, brought about by the phenomenon of perceptual constancy. The problem is that in conditions which are non-ideal, yet within the range that perceptual constancy works, we see things veridically despite an “appearance” which is traditionally taken to be non-veridical. For example, a tilted coin is often taken to have an “elliptical appearance”, shadowed surfaces a “darker appearance”. These appearances are puzzling for a number of reasons. I defend and elaborate on an approach taken by Sean Kelly, and earlier by the art historian E.H. Gombrich, according to which we can be tricked by our ability to bring about a kind of Gesltalt shift between different possible perceptual interpretations of a scene.

This paper advances the thesis that sensory concepts have as a semantic component the first-person indexical. It is argued that the private nature of our access to our own sensations forces, in our talking about them, an indexical reference to the inner states of the speaker in lieu of publicly accessible properties by which reference is usually fixed. Indexicals, such as ‘here’, can be understood despite ignorance of their referent. Such is the case with sensory terms. Furthermore, the thesis that sensory terms are indexical has considerable explanatory power. I give two examples: firstly, I argue that clashes of intuition over Block's ‘inverted spectrum’ thought experiment can be explained by appeal to semantic properties of indexicals. Secondly, I argue that multiple realisability intuitions can be shown to be consistent with the view that sensations are type-identical with brain states.

Representationalist theories of sensory experience are often thought to be vulnerable to the existence of apparently non-representational differences between experiences in different sensory modalities. Seeing and hearing seem to differ in their qualia, quite apart from what they represent. The origin of this idea is perhaps Grice’s argument, in “Some Remarks on the Senses,” that the senses are distinguished by “introspectible character.” In this chapter I take the Representationalist side by putting forward an account of sense modalities which is consistent with that view and yet pays due regard to the intuition behind Grice’s argument. Employing J.J. Gibson’s distinction between exploratory and performatory behaviour, I point to a proprioceptive element in perceptual experience, and identify this as crucial in any account of what makes a particular way of perceiving a sense modality

The representational theory of phenomenal experience is often stated in terms of a supervenience thesis: Byrne recently characterises it as the thesis that “there can be no difference in phenomenal character without a difference in content”, while according to Tye, “[a]t a minimum, the thesis is one of supervenience: necessarily, experiences that are alike in their representational contents are alike in their phenomenal character.” Consequently, much of the debate over whether representationalism is true centres on purported counter-examples – that is to say, purported failures of supervenience. The refutation of putative counter-examples has been, it seems to me, by and large successful. But there is a certain class of these for which the representationalist response has been something less than completely convincing. These are the cross-modality cases. I will explain what I mean, and then argue that the response in question is not only unconvincing but actually undermines the representationalist position.