I argue that Democritus presents a theory of colour in which the predominance of atomic shapes and microstructural arrangements are necessary but not sufficient for colour vision. Focusing primarily on Democritus’ basic colours, I analyse his microstructural account, providing a new analysis of the natural and technological underpinnings of his method of explanation. I argue that the notion of predominance allows Democritus to account for both the variation and the repeatable correspondence of colour perception by setting limits on possible microstructures. (...) This account, however, is complicated by the evidence for a Democritean theory of colour transformation and distorted vision, which arise from a dynamic interplay of features at the level of microstructures and at the level of perception. (shrink)

A theory of the structure and cognitive function of the human imagination that attempts to do justice to traditional intuitions about its psychological centrality is developed, largely through a detailed critique of the theory propounded by Colin McGinn. Like McGinn, I eschew the highly deflationary views of imagination, common amongst analytical philosophers, that treat it either as a conceptually incoherent notion, or as psychologically trivial. However, McGinn fails to develop his alternative account satisfactorily because (following Reid, Wittgenstein and Sartre) he (...) draws an excessively sharp, qualitative distinction between imagination and perception, and because of his flawed, empirically ungrounded conception of hallucination. His arguments in defense of these views are rebutted in detail, and the traditional, passive, Cartesian view of visual perception, upon which several of them implicitly rely, is criticized in the light of findings from recent cognitive science and neuroscience. It is also argued that the apparent intuitiveness of the passive view of visual perception is a result of mere historical contingency. An understanding of perception (informed by modern visual science) as an inherently active process enables us to unify our accounts of perception, mental imagery, dreaming, hallucination, creativity, and other aspects of imagination within a single coherent theoretical framework. (shrink)