Mary the Scientist
Philosopher Frank Jackson (1943—) describes another thought experiment about how subjective experiences are irreducible to physicalist accounts. Jackson imagines a neuroscientist, Mary, who has been locked in her lab since birth. She knows everything there is to know about vision:
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 specialises 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 wave-length 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.” (Jackson 1982, p. 130)
Her scientific knowledge about vision is supposedly complete. Mary has never been outside her room, and it is a peculiar room where things have no other colors than black and white. We can also imagine that she has been given a drug to make her skin, hair, and blood look white, and that there are no mirrors, so she cannot see the colors in her eyes. Mary has never seen any colors other than black, white, and shades between them.
Suppose Mary is let out and sees a red rose. Would her experience be entirely new, or not? Surely, she must have learned something when she sees the color red. Jackson finds this obvious:
Will she learn anything or not? It seems just obvious that she will learn something about the world and our visual experience of it. (Jackson 1982, p. 130)
He concludes that her knowledge must have been incomplete although she had all of the physical information:
But then it is inescapable that her previous knowledge was incomplete. But she had all the physical information. (Jackson 1982, p. 130)
Hence, physicalism must be false:
Ergo there is more to have than that, and physicalism is false. (Jackson 1982, p. 130)
Moreover, what goes for vision and color goes for the other experiences:
Clearly the same style of knowledge argument could be deployed for taste, hearing, the bodily sensations and generally speaking for the various mental states which are said to have (as it is variously put) raw feels, phenomenal features or qualia. The conclusion in each case is that the qualia are left out of the physicalist story. (Jackson 1982, p. 130)
Physicalism fails to account for experience (qualia). The mysterianist views of Levine, Nagel, and Jackson share a central concern—experience is physically inexplicable. They think we cannot wrap our heads around what it would mean for experience to be physical. But why? What fact about us makes it so? Let us get back to Colin McGinn, who tries to answer these questions.