 A number of proponents of this interpretation of the Knowledge Argument suggest that it is compatible with a specific form of physicalism, on which all facts are physical or metaphysically necessitated by microphysical facts but some facts can only be understood by having specific experiences (see, e.g., Kallestrup 2006; Howell 2007; for slightly different formulations see Crane 2003; Zhao 2012). That said, it is worth asking how the ‘physical’ is to be understood, such that facts which can only be known if one has certain experiences can count as physical. Furthermore, it is worth questioning whether a view on which facts are either physical or metaphysically necessitated by microphysical facts thereby counts as a form of physicalism. It has been argued that such a view is compatible with non-physicalist positions such as emergentism or certain forms of ethical non-naturalism (see Horgan 1993, 559-566; 2010, 311-314; Crane 2010; for discussion see Stoljar 2017, section 9).