The first logic machine. The volvelle — rotating disks that generate combinations — is a genuine, documented first for mechanised, combinatorial reasoning, and Leibniz explicitly traced his combinatorics to it.
It lists, it doesn't prove. The Art produces propositions by combination; it does not validate them. And its purpose was theological — to demonstrate doctrine — more mnemonic and contemplative than rigorous.
Right idea, early. The notion — mechanise reasoning by combination — was centuries ahead and became, through Leibniz, the spine of computing. The dream was sound even where the device was mystical.
Llull's first figure carried nine principles, the divine "dignities," lettered B through K: Goodness, Greatness, Eternity, Power, Wisdom, Will, Virtue, Truth, Glory. He set them on an inner wheel that turns inside an outer one. Spin it, and the pointer at the top reads off a new pairing of concepts — and behind it, the machine is quietly forming all nine pairs at once. Drag the wheel, or let it turn.
The point of the wheels is exhaustiveness: not to find one clever pairing, but to be sure you have them all. Nine principles taken two at a time give thirty-six distinct pairs — the grid below — and Llull's later figures stacked wheels to reach triples and beyond, the combinations exploding. This is the ars combinatoria, and it is exactly the seam Leibniz would pick up: that reasoning might be reduced to the systematic combination of basic terms.
"He invented an alphabet of human thoughts… and a way to combine them." — Leibniz, on what he took from Llull
Llull was a Majorcan courtier who, after religious visions in his thirties, gave his life to a single project: a universal "Art" that could demonstrate the truths of faith to Muslims and Jews by reason alone. He learned Arabic, wrote some 250 works in Catalan, Latin and Arabic (pioneering literary Catalan), travelled the Mediterranean to debate and convert, and — by tradition — was stoned to death on a mission to Tunis around 1316.
Gate kept on. Be clear about what the Art is and isn't. It is a brilliant combination generator — but it does not prove anything: spinning the wheels yields propositions, not verdicts on their truth, and its grand aim (mechanically demonstrating Christian doctrine) simply doesn't work. Much of Llullism is closer to a contemplative mnemonic, or even mysticism, than to rigorous logic, and later admirers from Bruno to Kircher pushed it toward the occult. The durable, vindicated kernel is narrow and real: the idea that reasoning could be mechanised by combining symbols on a machine. That idea, stripped of the theology, is what Leibniz inherited and what runs, eventually, in every processor. A first not of logic's content, but of its mechanisation.