Science is objective, experimental, quantitative; sense experience—indeed all mental experience—is subjective, experiential and qualitative. What this seems to show is that no physical description of the world, however complete, can capture what goes on in our minds. As philosophers put it, the mental is irreducible to the physical#1799•
Perhaps she would start by pointing out that there is a difference between appearances and reality: there is a way things are and a way they appear to be. Science concerns itself with the former, not the latter, because knowledge is always of how things are, not as they merely seem to be. Mary knows everything about what red is, she just doesn't 'know' how it appears to most people.
She does know how it appears to her, of course, which is like a particular shade of grey.#1798•