The challenge to philosophical intuitions is clear enough. Either they are analytic, in which they contain no substantial information, or they are synthetic, in which case they are of dubious reliability.[15]   Given this, a number of philosopher of naturalist inclinations advocate a revisionary attitude to philosophical method. Philosophy should turn away from intuitions, and instead engage directly with proper observational evidence. (Kornblith 2002, Knobe and Nichols 2008.)