There's a story who's details I can't recall well enough to even google for that's relevant here... There was a philosopher (Sartre?) who was to meet his frien

There's a story who's details I can't recall well enough to even google for that's relevant here... There was a philosopher (Sartre?) who was to meet his friend at a cafe in Paris. His friend was late, and as the philosopher sat drinking coffee and waiting, he realized that his friend's absence was present, and this this absence was different from the absence of all the other people who also weren't at the cafe.