 We have already surveyed the representational theory of sensory qualities. But there are also representational theories of “what it’s like” in the second sense (4). A common reply to the arguments of Nagel and Jackson (Horgan (1984), Van Gulick (1985), Churchland (1985), Tye (1986), Lycan (1987, 1990, 1996, 2003), Loar (1990), Rey (1991), Leeds (1993)) is to note that a knowledge difference does not entail a difference in fact known, for one can know a fact under one representation or mode of presentation but fail to know one and the same fact under a different mode of presentation. Someone might know that water is splashing but not know that H2O molecules are moving, and vice versa; someone might know that person X is underpaid without knowing that she herself is underpaid, even if she herself is in fact person X. Thus, from Mary’s before-and-after knowledge difference, Jackson is not entitled to infer the existence of a new, weird fact, but at most that of a new way of representing. Mary has not learned a new fact, but has only acquired a new, introspective or first-person way of representing one that she already knew in its neurophysiological guise.