I wonder if someone already wrote a book about it, but it would be nice to collect all the stories of philosophical conversions into one nice reference guide. I am thinking about examples like Rousseau’s realization that arts and sciences corrupt morals that came to him on the way to Vincennes in 1749 while he was on the way to visit jailed Diderot – since that resulted in 1751 treatise on arts and sciences, Rousseau’s first work, in a sense, Rousseau’s philosophical life begins at that conversion. Any examples for a future anthology?
Perverse Egalitarianism
an otherwise excellent blog
Perverse Egalitarianism 
Kant tells a variety of inconsistent stories about what started his work on the Critical Philosophy. Sometimes it’s Hume (as in the Prolegomena), sometimes it’s the Third Antinomy, sometimes it’s the vertigo felt at the idea that something “in me” is supposed to be about anything (see the famous letter to Marcus Hertz).
Though both are probably apocryphal, Wittgenstein has two such stories: The one about the toy cars in the French courtroom for the TLP, and then the one about the rude gesture (“What does this mean, eh?”) for the later philosophy.
Bernard Stiegler had a jailhouse conversion I think? Not familiar with his work though
Daniel, thanks for your input – I am myself very hesitant to include Kant as well, you’re right, he seems to have wanted to have a pivotal moment, or he had several of them and they all got confused along the way, after all, Kant wasn’t really a serious and scrupulous Kant-scholar with all the knowledge of what he said/wrote and when.
Pseudonym, jailhouse conversions are the best – can we dig up something on that subject?
I can also add Hamann’s London conversion that gave us Sturm und Drang (not directly, but through Hamann’s consequent influence) and therefore Romanticism, and thus maybe Schelling and Hegel…
P.S. Actually one might argue that Hamann’s conversion gives us “real” Kant since after Hamann returns to Konigsberg from Riga (having come back from London) in 1759, his old employer (Berens) asks none other than Kant to mediate a reconciliation between him and Hamann. It is in this context that Hamann writes to Kant on July 27, 1759 (a fateful date as some scholars believe) and mentions David Hume, assuming this is the actual first mention of Hume to Kant.
There’s Pascal’s, when he almost died after his coach nearly drove off a cliff. Though that’s as much a religious conversion as a philosophical one.
I should add Fichte, of course, his was very much a philosophical conversion, although I don’t have a good quote handy. And Reinhold too, though this one didn’t last very long.
I still want to hear more about Wittgenstein’s experience with the “rude gesture”…
“I still want to hear more about Wittgenstein’s experience with the “rude gesture”…”
I don’t have a citation handy (I know it from those little “Introduction to Wittgenstein” books — I recall it’s in at least one of the comic book versions), but the gesture in question was Sicilian, I believe. That hand-along-the-chin thing. The idea was that we were supposed to be able to analyze any meaningful statement into a form such that you could write it in the Tractatus’s Begriffschrift notation, and a friend of Wittgenstein’s made said rude gesture and asked how to go about writing that down in the canonical notation. This was supposed to have lead Wittgenstein to realize that there is a whole lot more to meaning than he’d had in mind in the TLP. (Like I said: almost certainly apocryphal. The bit about the little cars is at least something that did happen, and that LW did mention.)