ABSTRACT
This chapter discusses 'the Qualia problem'—which seems to arouse more passion than anything else in the philosophy of mind—by considering a closely connected problem, the problem of the secondary qualities. The trouble with the secondary qualities begins back in the beginning of the seventeenth century, with the rise of modern science. The Qualia problem haunts contemporary philosophy of mind. If the secondary qualities are 'pushed into the mind' they threaten to drag with them all other sensible qualities, for instance perceived shapes and motions. 'Qualia freaks' mostly think that the qualia constitute a major objection to Materialist views of the mind. The most plausible theory along these lines is that advanced by David Hilbert in his short book Color and Color Perception. Hilbert's book is much easier to read than most other work on colour. Robert Boyle compared the secondary qualities to keys that fit into locks in the person who perceives them.
