On the Physical Effect of Philosophy
"The Stoic philosopher Posidonius gave an example of the medicinal powers of philosophy when he experimented on his very own person in the presence of the great Pompei ... he was able to overpower a violent attack of gout by means of a lively attack on the Epicurean school; the attack of gout went down to his feet, never having been able to reach his heart and his head. And so he proved the immediate physical effect of philosophy..."
I. Kant, 'Announcement of the Near Conclusion of a Treaty for Eternal Peace in Philosophy' (1796), in Raising the Tone of Philosophy, ed. P. Fenves, p. 83.