GRICE E FERRARIS

 The fact that in the introduction of expressions for specific prehensions a demand is imposed on a further theory to define functions mapping such pre-hensions on to physical situations might well prove fatal to a sceptic about the material world. How can such a sceptic, who is unsceptical about descriptions of sense-experience, combine the demand implicit in such descriptions with a refusal to assent to the existence of the physical situations which, it seems, the further theory would require in order to be in a position to meet the demand?