Pierre, last name unknown. Friend of J.-P. Sartre. Very little is known about Pierre, except that he was frequently not seen in cafés. cf. the following passage from Being and Nothingness:
I have an appointment with Pierre at four o'clock. I arrive at the café a quarter of an hour late. Pierre is always punctual. Will he have waited for me? I look at the room, the patrons, and I say, "He is not here." Is there an intuition of Pierre's absence, or does negation indeed enter in only with judgment? At first sight it seems absure to speak here of intuition since to be exact there could not be an intuition of nothing and since the absence of Pierre is this nothing. Popular consciousness, however, bears witness to this intuition. Do we not say, for example, "I suddenly saw that he was not there"? Is this just a matter of misplacing the negation?To be sure Pierre's absence supposes an original relation between me and this café for want of a real expectation which establishes their absence. But, to be exact, I myself expected to see Pierre, and my expectation has caused the absence of Pierre to happen as a real event concerning this café. It is an objective fact at present that I have discovered this absence, and it presents itself as a synthetic relation between Pierre and the setting in which I am looking for him. Pierre absent haunts this café and is the condition of its self-nihilating organization as ground.
Being and Nothingness, pp 40-42.