Ramon Llull (around 1232 to 1316) was a Majorcan philosopher, theologian, and missionary who set out to build a universal method for discovering and demonstrating truths. His system, developed across many works and refined into the Ars generalis ultima (the Great Universal Art) around 1305, reduced knowledge to a small alphabet of fundamental principles - nine letters B through K standing for concepts such as goodness, greatness, power, wisdom, and truth - and then combined them mechanically to generate statements.
The Art was not only a notation but a device. Llull drew figures as concentric paper discs that could be rotated against one another so that the letters lined up in every possible pairing and triple. By turning the discs, a user could systematically run through combinations - a two-letter pairing alone could be read in dozens of ways - and read off the propositions the system produced, rather than inventing arguments by hand. This is an early example of treating reasoning as a combinatorial, rule-governed process that a mechanism can carry out.
Llull’s Art was studied for centuries and directly inspired Gottfried Leibniz, who dreamed of a “calculus ratiocinator” that would settle disputes by calculation. The line from Llull’s spinning discs to Boole’s algebra of logic, to Jevons’s logic piano, and on to symbolic AI is a long one, but Llull stands near its medieval beginning: the idea that truth could be produced by combination and machinery, not only by insight.