“Let Us Calculate”
We will never hear Leibniz’s voice. He died in 1716, two centuries before phonographs. But his 50,000 pages of surviving letters tell us exactly what kind of mind was behind it — and every contemporary who met him used the same word: inexhaustible.
Leibniz was the last universal genius, and he talked like one. Mathematics, philosophy, law, theology, engineering, diplomacy — he could discourse on any subject and frequently did, at length, to anyone who would listen. Voltaire later mocked him as “Dr. Pangloss” in Candide, the insufferable optimist who insists this is the best of all possible worlds while everything burns. The satire worked because the original was recognizable. Leibniz genuinely believed the universe was optimally constructed and could prove it with equations.
His linguistic landscape was multilingual: German native, French preferred for correspondence, Latin for scholarly works, some English. He wrote primarily in French and Latin, which tells you something about which audiences he cared about. His German was Leipzig/Hanover educated Saxonian — the accent of the intellectual elite, not the folk. Contemporaries described him as witty, sociable, and relentlessly enthusiastic about ideas, the opposite of Newton’s reclusiveness. Where Newton brooded alone in Cambridge, Leibniz charmed courts across Europe.
50,000 Pages of Letters
The surviving correspondence — over 50,000 pages, much of it still being edited and published — provides the primary evidence. Letters to virtually every major intellectual in Europe reveal a mind that moved between topics with stunning speed and genuine delight. The calculus priority dispute with Newton consumed his final years and reveals a different register: defensive, wounded, insistent on credit he deserved. Voltaire’s Candide (1759) provides the unflattering but recognizable caricature.
German Thinking, French Writing
Leipzig/Hanover educated Saxonian German, but Leibniz spent most of his intellectual life writing in French and Latin. The German accent would have been precise and scholarly. His spoken French would have carried German coloring. He moved between three languages the way he moved between disciplines — constantly, enthusiastically, without visible effort.
His most famous line — “This is the best of all possible worlds” — is the one Voltaire turned into a punchline. But Leibniz meant it as a logical proposition: if God is omniscient and benevolent, then the world as constituted must be the optimal arrangement. The optimism wasn’t naive. It was mathematical. His proposed method for resolving all philosophical disputes was even more striking: “Let us calculate.” Reduce the question to symbols, run the computation, accept the answer. It sounds absurd. It also describes the future of artificial intelligence, three centuries before it existed.
The Last Universal Genius, Alone
It is 1714. Leibniz is sixty-eight, writing the Monadology in French from Hanover, laying out his complete metaphysical system in ninety paragraphs. He is simultaneously corresponding with dozens of scholars, advising the Hanoverian court on legal matters, designing a calculating machine, and fighting bitterly with Newton’s supporters over who invented calculus. The voice in the letters is enthusiastic, precise, and tireless — a man who begins every conversation by connecting your question to three other fields you hadn’t considered. He has been called the last man who knew everything. The title is approximately accurate. He will die two years later, alone, his employer having left for England to become King George I. No one attended his funeral except his secretary. The man who corresponded with all of Europe died with nobody in the room.
Sources
- Leibniz, Gottfried Wilhelm. Monadology. 1714.
- Voltaire. Candide, or Optimism. 1759.
- Antognazza, Maria Rosa. Leibniz: An Intellectual Biography. Cambridge University Press, 2009.
- The Leibniz-Edition, Berlin-Brandenburg Academy of Sciences (ongoing publication of collected works and correspondence).