Colour Inversion Problems for Representationalism

In this paper I examine whether representationalism can account for various thought experiments about colour inversions. Representationalism is, at minimum, the view that, necessarily, if two experiences have the same representational content then they have the same phenomenal character. I argue that representationalism ought to be rejected if one holds externalist views about experiential content and one holds traditional externalist views about the nature of the content of prepositional attitudes. Thus, colour inversion scenarios are more damaging to externalist representationalist views than have been previously thought. More specifically, I argue that representationalists who endorse externalism about experiential content either have to become internalists about the content of prepositional attitudes or they have to adopt a novel variety of externalism about the content of prepositional attitudes. This novel type of prepositional attitude externalism is investigated. It can be seen that adopting it forces one to reject Putnam's and Burge's externalist considerations about the nature of the prepositional attitudes.     

Fine-Grained Colour Discrimination without Fine-Grained Colour

René Jagnow [2012] argues that David Rosenthal's theory of consciousness cannot account for certain experiences that involve colours so fine-grained that we do not and cannot have concepts of them. Jagnow claims that an appeal to comparative concepts such as being slightly darker than cannot help Rosenthal, since, in order to apply such concepts, we would already need to be conscious of two distinct fine-grained colours. The present paper contests this claim. It appeals to the Cornsweet illusion and some other visual phenomena, in order to argue that our visual systems can and do represent brutely comparative matters.     

Colour constancy and Fregean representationalism

All representationalists maintain that there is a necessary connection between an experience’s phenomenal character and intentional content; but there is a disagreement amongst representationalists regarding the nature of those intentional contents that are necessarily connected to phenomenal character. Russellian representationalists maintain that the relevant contents are composed of objects and/or properties, while Fregean representationalists maintain that the relevant contents are composed of modes of presentation of objects and properties. According to Fregean representationalists such as David Chalmers and Brad Thompson, the Fregean variety of the view is preferable to the Russellian variety because the former can accommodate purported counterexamples involving spectrum inversion without illusion and colour constancy while the latter cannot. I maintain that colour constancy poses a special problem for the Fregean theory in that the features of the theory that enable it handle spectrum inversion without illusion cannot be extended to handle colour constancy. I consider the two most plausible proposals regarding how the Fregean view might be developed in order to handle colour constancy—one of which has recently been defended by Thompson (Australas J Philos 87:99–117, 2009)—and argue that neither is adequate. I conclude that Fregean representationalism is no more able to accommodate colour constancy than is Russellian representationalism and, as such, ought to be rejected.     

Constraints on Colour Category Formation

This article addresses two questions related to colour categorization, to wit, the question what a colour category is, and the question how we identify colour categories. We reject both the relativist and universalist answers to these questions. Instead, we suggest that colour categories can be identified with the help of the criterion of psychological saliency, which can be operationalized by means of consistency and consensus measures. We further argue that colour categories can be defined as well-structured entities that optimally partition colour space. We provide some empirical support for this claim by presenting experimental results, which indicate that internal structure is a better predictor of colour categories than perceptual saliency.     

Colour associates to semantic linear orders

Summary People were asked whether they had strong colour associates (rather than associations) for different linear orders. Eighteen informants responded that they associated colours with numbers, and ten that they associated colours with the days of the week. The colours associated with both linear orders were consistent between subjects and correlated with each other. The order of the associates correlated with the order noted in the anthropological linguistic typology of Berlin and Kay (1969). Together, the patterns noted indicate that the association of colours with linear orders is an orderly cognitive phenomenon. While no causal explanation of the phenomenon is given, some implications are suggested.     

Colour inputs to random-dot stereopsis.

Recently it has been claimed by Livingstone and Hubel that, of three anatomically and functionally distinct visual channels (the magnocellular, parvocellular interblob, and blob channels), only the magnocellular channel is involved in the processing of stereoscopic depth. Since the magnocellular system shows little overt colour opponency, the reported loss of the ability to resolve random-dot stereograms defined only by colour contrast seems consistent with this view. However, Julesz observed that reversed-contrast stereograms could be fused if correlated colour information was added. In the present study, 'noise' (non-corresponding) pixels were injected into random-dot stereograms in order to increase fusion time. All six subjects tested were able to achieve stereopsis in less than three minutes when there was only correspondence in colour and not in luminance, and three when luminance contrast was completely reversed. This ability depends on information about the direction of colour contrast, not just the presence of chromatic borders. When luminance and chromatic contrast are defined in terms of signal-to-noise ratios at the photoreceptor mosaic, chromatic information plays at least as important a role in stereopsis as does luminance information, suggesting that the magnocellular channel is not uniquely involved.     

Linguistic Basicness and Colour Information Processing

Berlin and Kay's notion of basicness was defined by a combination of linguistic and psychological criteria, but they suggested that the psychological criteria might be extended. The experiments reported here were designed to explore a possible extension by searching for perceptual effects of basicness. Russian speakers who have two basic terms for the blue region of colour space were compared with English speakers who have only one basic term for the same region on two perceptual tasks. The first two experiments sought for greater Stroop interference for the Russians than for the English for the critical “blue” stimuli, and the third experiment sought greater perceptual differentiation for the Russians in the blue region. All experiments clearly replicated standard findings, but all singularly failed to find the predicted differences between the two groups. It is argued that whilst the results are consistent with there being no psychological effect of basicness, it is necessary to search for possible effects in other domains, such as recognition memory, before accepting this conclusion.     

Colour vision brings clarity to shadows

We have revealed a new role for colour vision in visual scene analysis: colour vision facilitates shadow identification. Shadows are important features of the visual scene, providing information about the shape, depth, and movement of objects. To be useful for perception, however, shadows must be distinguished from other types of luminance variation, principally the variation in object reflectance. A potential cue for distinguishing shadows from reflectance variations is colour, since chromatic changes typically occur at object but not shadow boundaries. We tested whether colour cues were exploited by the visual system for shadow identification, by comparing the ability of human test subjects to identify simulated shadows on chromatically variegated versus achromatically variegated backgrounds with identical luminance compositions. Performance was superior with the chromatically variegated backgrounds. Furthermore, introducing random colour contrast across the shadow boundaries degraded their identification. These findings demonstrate that the visual system exploits inbuilt assumptions about the relationships between colour and luminance in the natural visual world.     

Colour Discrimination And Monitoring Theories of Consciousness

According to the monitoring theory of consciousness, a mental state is conscious in virtue of being represented in the right way by a monitoring state. David Rosenthal, William Lycan, and Uriah Kriegel have developed three different influential versions of this theory. In order to explain colour experiences, each of these authors combines his version of the monitoring theory of consciousness with a specific account of colour representation. Even though Rosenthal, Lycan, and Kriegel disagree on the specifics, they all hold that colours are represented by a single type of mental state. The main goal of this paper is to show that a more complex account of colour representation is needed for the monitoring theory of consciousness to do justice to the phenomenology of colour experiences. In particular, I will argue that the fine-grained character of colour experience—that is, the fact that perceivers can become conscious of small differences between colours—requires that colour representation be construed in terms of two different types of mental states, namely sensory states that represent appearance properties and colour representations that represent physical colours.     

Surface Colour is not a Perceptual Content

In this paper, I consider a view that explains colour experience by the independent representation of surface and illumination. This view implies that surface colour is a phenomenal perceptual content. I argue from facts of colour phenomenology to the conclusion that surface colour is not a phenomenal perceptual content. I then argue from results of surface-matching experiments to the conclusion that surface colour is neither a perceptual content of any kind nor any sort of computational output of the perceptual system. These conclusions contradict widely accepted views in both the philosophy of perception and colour science. I finish by considering and rejecting a competing account of the surface-matching results, according to which surface colour is represented indeterminately in perception.     

Colour, world and archimedean metaphysics: stroud and the quest for reality

This paper proposes a fundamentally opposite conception of the possibility of metaphysics to that of Barry Stroud in The Quest for Reality and other writings. I discuss Stroud’s views on everyday ‚truth’ and metaphysics (Section 1), on interpretation (Section 2 – replying with a theory of ‚quasi-understanding’), and his ‚no threat’ claim (Section 3). But the main argument (Section 4) is a response to Stroud’s claim that we have no right either to affirm or to deny the metaphysical reality of colours. Stroud’s view resembles Carnap’s (1950, Revue Internationale de Philosophie 4, 20–40), that experience can in some sense never settle the metaphysical issue between e.g. materialism, idealism and phenomenalism; though we can allow everyday ‚knowledge’ e.g. that there is a fallen tree in the garden outside, as something available on all three views. (Carnap takes the undecidability as a sign that the metaphysical issue is a pseudo-question; Stroud insists it is factual, but places it beyond our ken, ‚external’.) I argue, instead, that metaphysical argument is possible from within our conceptual scheme and epistemic situation (as in Gareth Evans’s arguments for realism over phenomenalism); that ‚external’ and ‚internal’ questions cannot be separated as Stroud wishes; and that if we really were denied knowledge on ‚metaphysical’ matters, that would infect our right to claim knowledge of ‚observational’ matters too. And I sketch a theory of colour that would allow us to conclude (at once ‚metaphysically’ and ‚internally’) that things are indeed ‚really’ coloured. For all his expressions of sympathy for Wittgenstein, Stroud’s metaphysics is remarkably Cartesian.