 However, the compatibilist may ask why this is supposed to be a problem (McLaughlin &amp; Tye, 1998a, b, c). The indeterminacy may show only that Oscar’s concept is vague and not that Oscar fails to possess any concept whatsoever. (Brown 2001 replies by defining ‘agnostic’ so it applies only if the concept is non-vague. Yet Brown 2004, ch. 8 concedes that Oscar then can no longer know apriori if he is “agnostic.”) So, here too, it seems that EXT does not reveal apriori that water thoughts metaphysically require a content specific environmental condition.