(1) The induced colours led to perceptual grouping and pop-out, (2) a grapheme rendered invisible through ‘crowding’ or lateral masking induced synaesthetic colours — a form of blindsight — and (3) peripherally presented graphemes did not induce colours even when they were clearly visible. Taken collectively, these and other experiments prove conclusively that synaesthesia is a genuine percep- tual phenomenon, not an effect based on memory associations from childhood or on vague metaphorical speech. We identify different subtypes of number–colour synaesthesia (...) and propose that they are caused by hyperconnectivity between col- our and number areas at different stages in processing; lower synaesthetes may have cross-wiring (or cross-activation) within the fusiform gyrus, whereas higher synaesthetes may have cross-activation in the angular gyrus. This hyperconnec- tivity might be caused by a genetic mutation that causes defective pruning of con- nections between brain maps. The mutation may further be expressed selectively (due to transcription factors) in the fusiform or angular gyri, and this may explain the existence of different forms of synaesthesia. If expressed very diffusely, there may be extensive cross-wiring between brain regions that represent abstract concepts, which would explain the link between creativity, metaphor and synaesthesia (and the higher incidence of synaesthesia among artists and poets). Also, hyperconnectivity between the sensory cortex and amygdala would explain the heightened aversion synaesthetes experience when seeing numbers printed in the ‘wrong’ colour. Lastly, kindling (induced hyperconnectivity in the temporal lobes of temporal lobe epilepsy [TLE] patients) may explain the purported higher incidence of synaesthesia in these patients. We conclude with a synaesthesia-based theory. (shrink)

Most objectivist and dispositionalist theories of color have tried to resolve the challenge raised by color variations by drawing a distinction between real and apparent colors. This paper considers such a strategy to be fundamentally erroneous. The high degree of variability of colors constitutes a crucial feature of colors and color perception; it cannot be avoided without leaving aside the real nature of color. The objectivist theory of color defended in this paper holds that objects have locally many different objective (...) colors. Most color variations are then real and result from the extreme richness of color properties. (shrink)

I propose a counterexample to naturalistic representational theories of phenomenal character. The counterexample is generated by experiences of novel colours reported by Crane and Piantanida. I consider various replies that a representationalist might make, including whether novel colours could be possible colours of objects and whether one can account for novel colours as one would account for binary colours or colour mixtures. I argue that none of these strategies is successful and therefore that one cannot fully explain the nature of (...) the phenomenal character of perceptual experiences using a naturalistic conception of representation. (shrink)

This appeared in Philosophy and Phenomenological Research 59:473-93, as a response to four papers in a symposium on my book The Conscious Mind . Most of it should be comprehensible without having read the papers in question. This paper is for an audience of philosophers and so is relatively technical. It will probably also help to have read some of the book. The papers I’m responding to are: Chris Hill & Brian McLaughlin, There are fewer things in reality than are (...) dreamt of in Chalmers’ philosophy Brian Loar, David Chalmers’ The Conscious Mind Sydney Shoemaker, On David Chalmers’ The Conscious Mind Stephen Yablo, Concepts and consciousness Contents. (shrink)

This expanded edition of C L Hardin's ground-breaking work on colour features a new chapter, 'Further Thoughts: 1993', in which the author revisits the dispute ...

Dieser Band präsentiert den Text der Originalausgabe von 1907, drei weitere Arbeiten über ein optisches Paradoxon sowie sieben bisher unveröffentlichte Basisuntersuchungen zum Problem Sinneswahrnehmungen, die Brentano in eine zweite ...

The topic of a priori knowledge is approached through the theory of evidence. A shortcoming in traditional formulations of moderate rationalism and moderate empiricism is that they fail to explain why rational intuition and phenomenal experience count as basic sources of evidence. This explanatory gap is filled by modal reliabilism -- the theory that there is a qualified modal tie between basic sources of evidence and the truth. This tie to the truth is then explained by the theory of concept (...) possession: this tie is a consequence of what, by definition, it is to possess (i.e., to understand) one’s concepts. A corollary of the overall account is that the a priori disciplines (logic, mathematics, philosophy) can be largely autonomous from the empirical sciences. (shrink)

We studied two otherwise normal, synaesthetic subjects who `saw' a speci¢c colour every time they saw a speci¢c number or letter. We conducted four experiments in order to show that this was a genuine perceptual experience rather than merely a memory association. (i)The synaesthetically induced colours could lead to perceptual grouping, even though the inducing numerals or letters did not. (ii)Synaesthetically induced colours were not experienced if the graphemes were presented peripherally. (iii)Roman numerals were ine¡ective: the actual number grapheme was (...) required. (iv)If two graphemes were alternated the induced colours were also seen in alternation. However, colours were no longer experienced if the graphemes were alternated at more than 4 Hz. We propose that grapheme colour synaesthesia arises from `cross-wiring' between the `colour centre' (area V4 or V8)and the `number area', both of which lie in the fusiform gyrus. We also suggest a similar explanation for the representation of metaphors in the brain: hence, the higher incidence of synaesthesia among artists and poets. (shrink)

I propose a description of one aspect of the philosophical problem about the ontology of colors by formulating and motivating six plausible premises that seem to be hard to deny in isolation but that are jointly incoherent. I briefly sketch a solution and comment on the views presented in this volume from the perspective of the puzzle.

Could there be genuinely novel colours — that is, visual qualities having a hue that bears a resemblance relation to red, green, yellow, and blue, yet is neither reddish, nor greenish, nor yellowish, nor blueish?1 And if there could be such colours, what would it be like to see them? How would the colours look? In his article,"Epiphenomenal Qualia,"2 Frank Jackson presents a philosophical thought experiment that raises these questions . Jackson asks us to imagine a perceiver named Fred who (...) is like us except that he has the ability to see a hue we cannot see. Jackson's question is: "What is the new colour or colours like?"3 Jackson argues that all the physical information about Fred, including the physiology of his brain and visual system, and his dispositions to behaviour, would not enable us to answer this question. The totality of physical information would still leave out something about Fred's experience, namely, what the extra hue is like from the subjective perspective of Fred. And if at some point we became able to see this extra hue , we would learn something that we did not know as a result of having all the physical information about Fred: We would learn how the extra hue looks and thereby learn just what it was that made Fred's experience different from ours. Jackson calls his argument "the knowledge argument." In his view, the argument is similar to Thomas Nagel's in his article "What is it Like to Be a Bat?,"4 but both its point and ultimate conclusion are different. Nagel argues that facts about what conscious experience is like for some creature are essentially connected to the subjective perspective of the creature. The problem that Nagel poses is, how could such facts be revealed in anything objective and physical about the creature? How could the objective characterization indicate what it is like to be the creature ? The point of Jackson's argument, however, is not that we would not know what it is like to be Fred even if we knew everything physical about him ; it is rather that there is still something we do not know about Fred's experience — a property that it has — even when we have all the physical information about him: We do not know how the extra hue that Fred sees looks to Fred, and so we do not know all that there is to know about how Fred's experience of seeing the extra hue differs from his experience of seeing red, green, yellow, and blue.5 Jackson's conclusion is also stronger than Nagel's. (shrink)