An evening at Bellosguardo

Galileo's villa at Bellosguardo looks out over Florence, and he has set up his best telescope for the evening. Kepler, whose eyesight is poor, listens as Galileo describes the mountains on the moon; Descartes, then thirty-two and on a tour of Italy, has come out of curiosity about the man and the instrument.

The talk moves from what the telescope shows to what it can be trusted to show, and from there to the foundations of knowledge itself. Descartes is already turning over the doubt that will consume him; Galileo wants certainty from observation, and Kepler wants it from geometry. They eat a pullet, a herb pottage, and marchpane, and part without resolving anything, which none of them minds.