H. P. Grice: At some early stage in the attempted regression the calculations required of A by U will be impracticably difficult; and I suspect the limit was reached (if not exceeded) in the examples which prompted the addition of a fourth and fifth condition. So U could not have the intention required of him in order to force the addition of further restrictions. Not only are the calculations he would be requiring of A too difficult, but it would be impossible for U to find cues to indicate to A that the calculations should be made, even if they were within A's compass. So one is tempted to conclude that no regress is involved.

 At some early stage in the attempted regression the calculations required of A by U will be impracticably difficult; and I suspect the limit was reached (if not exceeded) in the examples which prompted the addition of a fourth and fifth condition. So U could not have the intention required of him in order to force the addition of further restrictions. Not only are the calculations he would be requiring of A too difficult, but it would be impossible for U to find cues to indicate to A that the calculations should be made, even if they were within A's compass. So one is tempted to conclude that no regress is involved.