Ramon Llull

Majorcan philosopher, missionary, and logician (c. 1232–1316) whose Ars combinatoria proposed rotating concentric wheels of terms as a device for generating and combining arguments — often cited as the earliest Western attempt at a reasoning apparatus. Matters to this vault because W. Stanley Jevons's own 1870 paper names Llull directly, in order to distinguish his own working machine from an earlier and, in Jevons's judgment, unsuccessful one: Jevons calls Llull's scheme a "futile scheme of a mechanical syllogistic" — a set of diagrams, not a working mechanism — the one prior attempt at reasoning-by-apparatus the paper acknowledges before claiming priority for a device that actually performs deduction. Six centuries separate Llull's combinatorial wheels from Jevons's working elimination machine; Jevons's own framing is the vault's primary-source anchor for why the two are not the same kind of thing.

References

• claim-jevons-1870-paper-received-16-oct-1869-read-20-jan-1870-royal-society
• claim-jevons-logic-piano-1869-mechanical-inference-machine