THIS, THEN, WAS THE MAN whom his father had to amuse with his mechanical head. Now, it so happens that the frigid winter morning on which the astronomer and his father set out to obtain an audience with the Emperor was the sixteenth morning of an interminable astronomical disputation the latter had convened at the Castle for the purpose of determining whether the new twinkling thing which had recently appeared in the heavens dwelled above or below the sphere of the Moon, and therefore deserved or did not deserve to be called a star. At once intrigued and tormented by that object’s inexplicable emergence and enigmatic meaning, the Emperor had summoned not merely every astronomer in the realm (“minus of course myself!”) but also freethinkers from the Low Countries, Oxford theologians, Jesuit mathematicians from the Collegio Romano, and Peripatetic schoolmen from Padua, who came north on horseback or sailed south up the Elbe or in one case scrambled (“just as you scrambled!”) over these very mountains on foot. From the far-flung window of their workshop the astronomer and his father could see the skylights of the Castle’s Great Hall pop open and a slew of astronomical contraptions emerge into the Prague sky, where they were whipped about by the crazed winter winds. A big brass something-or-other groaned over the city. It is said, the astronomer said, that Emperor Maximilian, upon learning that Rudolf intended to abandon the Hofburg and all that he’d accomplished there and move the imperial capital to Prague, had decreed on his deathbed that nothing in Prague rise higher than the steeple of the Cathedral of Saint Vitus—“Nothing higher!” At that moment, the tale went, he had a stroke that robbed from him for the final forty-eight hours of his life all of his language except the words “no,” “higher,” “steeple,” and “Vitus,” with which he emphatically filled the silence. In his last hour he retained only the word “no,” but “everyone understood the gist of what he was saying,” the astronomer told Leibniz. It was not as though the dying Emperor had constructed that steeple, the steeple was centuries old, no, this was “a pure posthumous filial constriction.” “The gratuitousness of it amazes me still.” But some of these contraptions soared higher than the steeple, and some even soared much higher. Our search for truth inevitably makes a mockery of our fathers’ deathbed decrees, not as an empirical matter but as a logical one, since what we mean by truth and where we look for it are obviously defined, in negative, by nothing other than what our fathers decree on their deathbeds, construed loosely to include their decades of decline. “Is your father dead?” the astronomer asked Leibniz, and Leibniz said yes. “Then this isn’t news to you,” the astronomer said, and Leibniz said no, it was not, although as he noted parenthetically to the Philosophical Transactions he was merely appeasing the astronomer on this point since he had nothing but the fondest memories of his father, a professor of moral philosophy at Leipzig who had died when Leibniz was six years old and with whose beliefs Leibniz’s own were in “perfect accord.” (Two years before his death half a century later, in an often-quoted 1714 letter to Nicolas Remond, Chief Counselor to the Duke of Orleans, in which he provides a brief polished account of his own philosophical development, Leibniz would claim to “possess no memories of my father,” and deem his father’s philosophy to be “of no especial interest.”) Now, the astronomer went on, hoisting onto his lap his plump cat, who without opening his eyes began to purr, some of these contraptions were quite sophisticated, and some were quite large, and one, the big groaning brass one, was both sophisticated and large, but all of them, as anyone could plainly see, were nothing but naked-eye astronomical contraptions, contraptions only as powerful as the eyes that peered into them, contraptions which in no way transcended us.