Page History

...

He may also be said to admit it implicitly when he typically grants that, simply as abstract concepts, "concreteness" and "abstractness" are related symmetrically, each requiring the other if either is to be a meaningful concept; and that it is only when one adverts to "concrete things or realities," as distinct from "concreteness" and "abstractness" as abstract concepts, that the important asymmetry between them becomes apparent – -- namely, because "concreteness . . . is the inclusive idea" (cf., e.g., "Duality versus Dualism and Monism": 52-55).

...