Last night I covered a big section of “The Conscious Mind” talking about various conceptions of and response to Mary’s Room. The best responses in Chalmer’s estimation are the ability responses. Mary didn’t have new knowledge upon seeing red for the first time, she just had another ability. I follow this response to an extent. But I think it gets to a deeper issue, that knowledge and abilities are closely tied together and even the coldest scientific theories don’t represent the world in itself but as constructed by brains and as ran as programs within brains which ‘contain’ the knowledge rather than lists of propositions on paper.
In other words, one reason why it’s hard to respond to this knowledge argument is it assumes an impossible ideal, that a person can have absolute propositional knowledge of everything – that there is a such thing in principle as perfect representation.