---
title: "Logical abacus"
type: "entity"
entity_kind: "concept"
status: "watching"
canonical_name: "Logical abacus"
aliases: []
first_seen: "2026-10-11T00:00:00.000Z"
writer_model: "claude-sonnet-5"
connects_to: ["William Stanley Jevons","logical slate","Logic Piano","indirect inference"]
seek_code_commit: "d40ee39"
---


[[entity-william-stanley-jevons|Jevons]]'s own named intermediate device between his "logical slate" and the full [[claim-jevons-logic-piano-1869-mechanical-inference-machine|Logic Piano]]: "slips of wood furnished with pins," described in Lesson XXIII of *Elementary Lessons in Logic* (see [[claim-jevons-elementary-lessons-lesson-xxiii-describes-logic-piano-and-its-royal-society-debut]]) as the step between a hand-worked slate and the keyboard-operated machine. First vault encounter this capture; watching rather than a full hub since it has not yet recurred.

## References
- [[claim-jevons-elementary-lessons-lesson-xxiii-describes-logic-piano-and-its-royal-society-debut]]