He told Leibniz: “He was a stranger wearing my face.”

One winter night, years into a cohabitation that had long since turned taciturn and cold, the astronomer, having combed every inch of the heavens with his seventy-five-foot tube and found only three stars that he had not seen through his previous tube, of seventy feet, and who, in consequence, was suffused with the ecstatic awareness that he was finally approaching the goal toward which everything had been directed, dreamily let the tube drift, and it drifted toward the portion of the heavens known to the Greeks as the Milky Way and to the Germans as the Way to the Shrine of Saint Jacob, and there he saw something he did not expect.

He roused the boy and ordered him to look through the tube. “What do you see? Tell me what you see!”

The boy looked through the tube. And after a moment he murmured: “It is beautiful.”

“I am not asking you if it’s beautiful,” the astronomer said. “That you find it beautiful is absolutely immaterial to me. I am asking you what it is.”

And the boy, who by now was a young man, replied: “What it is, Father, is a rather beautiful illustration of the futility, the farcicality, and the senselessness of your life. That is what I see through the tube.” And he put on his boots and his coat and walked out of the observatory into the deep snow, and he did not return that day, or the next, or any of the days that followed. The astronomer said: “And he was not wrong, Herr Leibniz. For what we saw through the tube was that the nebulous substance that composes the Way to the Shrine of Saint Jacob consists of nothing but innumerable stars crowded close together.” Between his catalogue and the sky itself there was now almost as great a difference as there’d been when he began; and between an absurdly long tube and one that was infinitely long there was, he thought as he contemplated throwing himself out of a window of his observatory, perhaps less of a difference than he’d hoped.

“Fifteen minutes, darker and darker,” the astronomer added, peering into his telescope. Leibniz noted that whatever slight darkening he had formerly assented to had long since passed, and through the askew slat it was now as bright outside, and as blue, as it had ever been, or more so.