The Knowledge Argument

The knowledge argument is an argument against physicalism. We are to imagine that Mary is a person that learns every physical fact possible about vision, but since birth has lived only in a black and white room. Even if all physical facts are known to her through her black and white television and books, if she goes out to the colourful world, it seems that she will know something more - namely what it is like to experience colour.

If there is something more to know besides physical facts, then there must be knowledge that is not about physical facts. Therefore, physicalism (the doctrine that there are only physical facts about the world) is false.

One objection is that colour is related to physical facts as aesthetics are related to physical facts. It appears plausible that a particular wavelength of light enters our eye and therefore red is an experience that is subjective upon those facts. But beauty is so much more subjective than colour. We can diagnose someone as colour blind but no one is ever 'beauty blind'. There is something about colour and pain that is more solid fact and qualia like than the subjectiveness of aesthetics.

I think it is possible that colour is epiphenomenal, and furthermore, that all phenomenal experience is exhausted upon the knowledge of all physical facts. That is, knowing all the physical facts about the anatomy of our visual system will result in us knowing the exact nerve firing pattern N that results in E, a e.g. red experience. Even if Mary has never experienced redness, knowing N, and reproducing N in her brain will result in an experience that is indistinguishable as seeing red. There exists no other experience that lies beyond this possibility.