Leibniz: At that moment, way down at the foot of the wall, the astronomer thought: “Why, actually, is it absurd to think of seeing all the stars?”

Leibniz writes: What had struck him as a matter of logic plunged now into the realm of the empirical.

He would need no doubt a long tube, maybe a very long tube, and possibly even an absurdly long tube, but between an absurdly long tube and an impossibly long tube there was, “contra Descartes, who would have seen two equally dubious tubes,” Leibniz comments, all the difference in the world, the astronomer thought as he stood at the foot of the wall of the monastery.

And there was all the difference in the world between a star catalogue that was prodigious and one that was complete.

The astronomer had the sense that a complete star catalogue, an exhaustive star catalogue, the star catalogue God Himself were He to survey His creation would compose, a record in writing of everything above—“In this very ledger!” he said, holding above his head the ledger in which he’d been writing all morning—would, aside from expiating completely his own guilt, mean something momentous for man’s place in the cosmos.

What it would mean, momentous how, not to mention, he added, whom he thought he meant by man: all of this he did not yet know.

Now the Sun had risen. From the monastery the astronomer went straight to the Castle Workshop and demanded of his craftsmen a tube no less than three feet in length, forged of solid gold, and with the power to magnify things ninefold. But for the first time his metallurgists said: We cannot do that. So the astronomer said: Fine, then, make it of silver, as before, the tactile qualities of the tubes while significant are still secondary to the optical. But his metallurgists said: We cannot make it of silver either. And the astronomer shouted: Then of bronze, or brass, or iron, or lead, just so long as it magnifies objects nine times! And the metallurgists said: Not of bronze nor of brass, nor of iron nor lead. And the master lens-grinder from Nuremberg stepped forward and said: The Emperor has ordered us to make no more tubes for you. And his Augsburger apprentice said: I fear that you have not calculated the true cost of your celestial observations. If you have a place to go, go there, sir, I beg you, forget the stars, leave Prague.

He returned posthaste to the Imperial Observatory but found it padlocked. His own house he found padlocked, too. A note nailed to the door and stamped in red wax with the two-headed Habsburg eagle requested his presence in the North Wing “to discuss your future here, and the future of your tubes.”

The astronomer peered into his telescope, picked up his quill, and wrote something down.