 Once C1 and C2 are accepted, there is obviously no way to avoid C3 (which follows logically from the former two). Moreover, is seems hard to deny that it is in principle possible to have complete physical knowledge about human color vision (or about an appropriately chosen part thereof). If so, premise P1 should be accepted as an appropriate description of a legitimate thought experiment. To avoid the antimaterialist conclusion C3 the physicalist can (a) object against the inference from P1 to C1 (a minority of philosophers have chosen this strategy, see  Section 4.2  below) or he or she can avoid C2 by (b) denying premise P2 (this is the strategy chosen by proponents of the No Propositional Knowledge View, see Sections  4.3  and  4.5  below) or by (c) blocking the inference from premise P2 to C2 (this is the strategy chosen by a majority of physicalist philosophers who subscribe to some version of the New Knowledge/Old Fact View, see  Section 4.6  below).