Boy, it was tempting to put a big black page here with no text or links. But that wouldn't be very explanatory, would it? And if you've really bothered to follow these links to philosophical meanderings and scholarly references, I assume you're either bored, naturally curious, or you really would like some explanation. So here goes:
Nothingness is the putting into question of being by being -- that is, precisely consciousness or for-itself. It is an absolute event which comes to being by means of being and which, without having being, is perpetually sustained by being. Since being-in-itself is isolated in its being by its total positivity, no being can produce being and nothing can happen to being through being -- except for nothingness. Nothingness is the peculiar possibility of being and its unique possibility. Yet this original possibility appears only in the absolute act which realizes it. Since nothingness is nothingness of being, it can come to being only through being itself. Of course it comes to being through a particular being, which is human reality. But this being is constituted as human reality inasmuch as this being is nothing but the original project of its own nothingness. Human reality is being in so far as within its being and for its being it is the unique foundation of nothingness at the heart of being.
Being and Nothingness, p 126.
