“Three young  and brilliant philosophers — the good-hearted Jean-Paul Sartre, the elegant Simone de Beauvoir, and the debonair Raymond Aron — sat in a bar on Paris’s rue du Montparnasse sometime around 1932. As they sipped apricot cocktails, they discussed how philosophy could be about everyday things, like apricot cocktails. Galvanized by the tipsy banter, Sartre had an epiphany: ‘Finally there is philosophy.’ So recounts Sarah Bakewell in her new book, At the Existentialist Café: Freedom, Being, and Apricot Cocktails, throwing her reader into a world of dazzlingly brilliant and revolutionary 20th-century philosophers, including the aforementioned threesome, as well as Albert Camus, Martin Heidegger, Edmund Husserl, Karl Jaspers, and Maurice Merleau-Ponty. The ‘cast of characters’ also includes cameo appearances by Hannah Arendt, Frantz Fanon, Iris Murdoch, and about 68 others. Bakewell, author of three other books, most recently How to Live: Or A Life of Montaigne in One Question…