Art and Experience, Utrecht, © 1996. All rights reserved

Secondary qualities, due to their unimodal phenomenality cannot be explained without reference to the relevant mental aspect of perception--this is as tradition has it. Certain philosophers (such as Locke, and Mackie, not McDowell) even argue that secondary qualities are illusory for this reason. I argue that they too are polymodally accessible--with the help of samples and scientific devices--but that this does nothing to explain their phenomenality. However, the polymodal access to primary qualities does little in that area either. Polymodality does help proving a property's existence, and therefore both secondary and primary qualities are on equal footing in the last analysis. Polymodality involves 'translation' by perceptual imagination--due to the fact that the different senses structure the world in distinct ways. The phenomenality of primary and secondary properties is response-dependent, whereas the establishment of either kind's actuality isn't. Cf. tertiary qualities. (II:2-3; VII:8-9).