AS FOR HIS PHYSICAL APPEARANCE, apart from his missing eyes, Leibniz reported to the Philosophical Transactions, the old astronomer was shriveled-up and bony and hunched over, and had some white hair on his head but not a lot of it (though each strand was long, there were not many strands), and the skin of his neck sagged below his chin, and his nose was big, the big bent nose perhaps of an Israelite, though altogether his face emanated an aura of “amiability and intelligence.” Whenever the astronomer bowed his head to peer into the telescope, his head, from Leibniz’s vantage point, vanished completely behind the high jutting ridge of his shoulders; “his spinal column had probably deformed with age.” The astronomer wore the rags and furs of the goatherds Leibniz had passed on the ascent. “Nothing on his feet, nothing on his head.” “The possibility that he actually was a goatherd, who had lost his eyes, and his mind, and strolled into this observatory, and began calling himself ‘the astronomer,’ was of course not lost on me.” From the moment he first saw him, Leibniz was well aware that what the old man herded might be something quite other than “flocks of truth and falsity through the pastures of the kingdom of reason.”

On the next page: a drawing of the old man hunched over on his stool, at the eyepiece of the telescope, the lengths of his limbs and the angle at which he held his head marked with precision as though the man himself were part of his instrument. The caption reads: “Was he a goatherd?”