Proprium est unum, quod de pluribus praedicatur in quale necessarium, a “necessary” determination [»notwendige« Bestimmung] that belongs to the thing [Ding], but also lies outside of the essential context of genus and species. [GA18 GA18
GA18MT
GA 18
GA XVIII Grundbegriffe der aristotelischen Philosophie (Summer semester 1924), ed. M. Michalski, 2002, XIV, 418p. :16]