 Together with the distinction between mental and external existence (or existence in concrete individuals: fī l-ʿayān) Avicenna posits a distinction between the being of the thing and its existence. Clearly, then, the fundamental and primary character of being does not imply simplicity: to exist means to be a given entity in the world or—as Avicenna also uses it—a “thing” (Ilāhiyyāt, I, 5). The existence of something must thus be distinguished from its being what it is.