 “White” is not “horse” because ‘horse’ alone doesn’t pick out the white ones; only ‘white’ does. The sophist takes it as obvious that “horse” combined with “white” is not simply “horse.” Here he is “separating hard and white,” in that he explicitly treats “white” and “horse” (that is, the shape of the animal) as two things that are combined to form something more than, and different from, a horse. The argument again turns on construing “White horse is horse” as the claim that the kind white horse is identical to the kind horse.