Read another response by Peter Lipton
Read another response about Color
I am having trouble with secondary qualities, which are manufactured in the brain after receipt of digital signals from the sense organs. For example, if I see a green leaf, I know that chlorphyll molecules in the leaf transmit electromagnetic radiation of a frequency such as to produce a sensation of green in my brain. The problem is that all the empirical objects that I perceive are structures of secondary qualities, and these are all outside my head. So where are secondary qualities, inside my head, or outside?