Australian philosopher Frank Jackson’s thought experiment about Mary the color scientist, often called “the Knowledge Argument,” has been pumping philosophers’ intuitions with remarkable vigor since it first appeared in 1982: Mary is a brilliant scientist who is, for whatever reason, forced to investigate the world from a black and white room via a black and white television monitor. She specializes in the neurophysiology of vision and acquires, let us suppose, all the physical information there is to obtain about what goes on when we see ripe tomatoes, or the sky, and use terms like “red”, “blue”, and so on. She discovers, for example, just which wavelength combinations from the sky stimulate the retina, and exactly how this produces via the central nervous system the contraction of the vocal chords and expulsion of air from the lungs that results in the uttering of the sentence “The sky is blue”. What will happen when Mary is released from her black and white room or is given a color television monitor? Will she learn anything or not? It seems just obvious that she will learn something about the world and our visual experience of it. But then it is inescapable that her previous knowledge was incomplete. But she had all the physical information. Ergo there is more to have than that, and Physicalism [i.e., materialism, the denial of dualism] is false. [Jackson, 1982, p. 130] Jackson’s intuition pump excellently exposes to the light a lot of naïve thinking about the nature of color experience and the brain that no doubt serves people well most of the time, so we might grant that he nicely draws out some of the implications of folk theory. But his aim was to refute a hypothesis about the capacity of the physical sciences to account for all color phenomena. Of course in any real-world situation, somebody in Mary’s imagined position would learn something new because however much she knew about color, there would be lots of facts about physical effects of color she didn’t know.
Philosopher Daniel Dennett's Book Intuition Pumps