  So we have moved from D1, to Hm, to PS. At 152c8–152e1 Socrates adds that, in its turn, PS entails Heracleitus’ view that “All is flux,” that there are no stably existing objects with stably enduring qualities. The reason given for this is the same thought as the one at the centre of the cold-wind argument: that everything to which any predicate can be applied, according to one perception, can also have the negation of that predicate applied to it, according to an opposite perception with equally good credentials.