Being-In-Itself and Being-For-Itself

The fundamental ontological distinction of Being and Nothingness separates two modes of being that cannot be reduced to each other. Being-in-itself (l'être-en-soi) is the mode of things — the paper-knife, the rock, the table. A thing is what it is, fully, completely, without the gap between being and possibility that would make it something else. It has no interiority, no project, no possibilities that it is not yet but could become. Being-for-itself (l'être-pour-soi) is the mode of consciousness. Consciousness is always ahead of itself, always projecting toward possibilities that do not yet exist, always separated from any fixed identity by what Sartre called the nothingness at the heart of human reality. Consciousness is what it is not (the possibilities it projects toward) and is not what it is (any identity it might claim). The distinction is not a theoretical nicety; it is the structural basis for every other concept in Sartre's philosophy.