Quick question: Is colour in your head or on the computer screen?
If you aren’t a philosopher, your first response might be, ‘Does it really matter?’ In this case, it does. A class action lawsuit depends on it.
In the suit the question becomes: is Apple misrepresenting their MacBook and MacBook Pro if they advertise displays capable of millions of colours, when they are really just selling displays that allow the perception of millions of colours?
The plaintiffs in this class action lawsuit, Fred Greaves and Dave Gatley, complain in their filing:
The reality is that notwithstanding Apple’s misrepresentations and suggestions that its MacBook and MacBook Pro display “millions of colors,” the displays are only capable of displaying the illusion of millions of colors through the use of a software technique referred to as “dithering,” which causes nearby pixels on the display to use slightly varying shades of colors that trick the human eye into perceiving the desired color even though it is not truly that color.
There is a rich literature on the philosophy of colour. Somehow, I doubt any of it will be used in court.
The blogosphere’s Cult of Mac is ripe with commentary. Hat-tip to Ars Technica via Apple 2.0 via Slashdot. See also Engadget and Apple Insider.
Thought Capital 
I don’t know if it matters in a legal sense, but psychophysicists have long treated color as a psychological category, rather than a physical one. That is, color is in the head.