The astronomer stroked his cat, peered into his telescope, picked up his quill, and wrote something down. Only someone truly horrified by the heavens can derive such happiness from a horse, and, a fortiori, a cat, he said. When you see someone deriving not altogether too much happiness from a horse, or a cat, you see someone at ease in the world. “An aphorism,” declared the astronomer. “A man delighted by a cat is discomfited by existence, a man delighted by existence is discomfited by a cat.” A cat owner is invariably an individual not in possession of any consoling doctrines or articles of faith, just as an individual in possession of some such doctrine invariably has no cats. A man who believes he possesses both a cat and a consoling doctrine will discover at some dreadful moment, when his faith is put to the test, that his doctrine is not truly consoling, or, if it is, that his cat is not really a cat. In his blackest hour he discovers that the doctrine on which he has founded his life is itself without any foundation, or if it does have a foundation his cat is a dog, the astronomer said, according to Leibniz.

Leibniz wrote: “Here the notion entered my head, and I could neither dislodge it nor yet judge the truth of it, that the cat, too, was missing its eyes.”