Mary’s Room

In 1982 Frank Jackson imagined a scientist named Mary who has spent her entire life in a black-and-white room, learning about the world through a monochrome monitor. She specializes in the neurophysiology of color vision and acquires every physical fact there is to obtain about what happens when humans see ripe tomatoes or the sky—every wavelength, every retinal firing, every neural cascade, every word in every language for every shade of red. Then she walks out and sees a red tomato for the first time. Does she learn anything? Jackson’s answer was that it seems just obvious that she does—that her physical knowledge, however complete, had left something out. The argument from this observation became the knowledge argument, one of the most contested claims in philosophy of mind: if Mary learns a new fact on release, then the physical facts are not all the facts, and physicalism is false. What no one in