 If – in analogy to the de se case – some physical facts about color vision can be known in two different ways, – in a ‘physical way’ (under ‘physical concepts’) and in some other, non-physical way (under ‘non-physical concepts’), then it is possible to acquire new (non-physical) knowledge about a (physical) fact without thereby acquiring knowledge of a new fact (the very same fact may have been known before under its physical conceptualization). Many authors accept the weaker version of the argument but reject the stronger one for the reason just sketched: they admit that Mary gains new propositional knowledge but deny that she thereby comes to know facts that she did not know before in some other way. (These authors accept the first premise of both versions of the argument and the second premise of the first version as well, but they deny the second premise of the second version and insist that (2a) does not imply (2b)). Their position with respect to the knowledge argument will be called the New Knowledge/Old Fact-View (see  Section 4.6  below). Others deny even the weaker version V1 and claim that Mary does not gain any new propositional knowledge (no new knowledge about something that is the case, no factual knowledge). Their position will be called the No Propositional Knowledge View (see  Sections 4.3  and  4.5  below).