---
title: "Chrysippus of Soli"
type: "entity"
entity_kind: "person"
status: "hub"
canonical_name: "Chrysippus of Soli"
aliases: ["Chrysippus","Chryssipus"]
first_seen: "2026-07-12T00:00:00.000Z"
writer_model: "claude-opus-4-8"
connects_to: ["Stoic logic","disjunctive syllogism (modus tollendo ponens)","reasoning by elimination","the three-road dog","William Stanley Jevons"]
seek_code_commit: "b13747c"
---


Greek philosopher (c. 279 – c. 206 BCE), the third head of the Stoa and the principal
systematizer of Stoic propositional logic — the ancient logic of connectives ("if,"
"or," "and," "not") that runs parallel to, and in places ahead of, Aristotle's logic of
terms. He is the ancient source of the stock example of a hunting dog that, reaching a
fork of three roads and rejecting two by scent, takes the third without sniffing —
reasoning by elimination, the disjunctive syllogism made vivid.

Matters to this vault as the origin-point of the reasoning-by-elimination thread the
vault traces forward through Jevons's Logic Piano to symbolic AI. The three-road dog
anchors [[claim-chrysippus-dog-disjunctive-syllogism]] and the cross-time recurrence in
[[observation-reasoning-by-elimination-from-stoic-logic-to-symbolic-ai]]; the specific
question of whether [[entity-william-stanley-jevons|Jevons]] drew on the dog was
investigated directly this session and answered with a nuance worth keeping — Jevons
did quote the dog in *Pure Logic* (1864), but not as a model for mechanization
([[claim-jevons-quoted-chrysippus-dog-in-pure-logic-1864]]).

## References
- [[claim-chrysippus-dog-disjunctive-syllogism]]
- [[observation-reasoning-by-elimination-from-stoic-logic-to-symbolic-ai]]
- [[claim-jevons-quoted-chrysippus-dog-in-pure-logic-1864]]
- [[claim-jevons-derived-logic-machine-from-indirect-inference]]
- [[claim-jevons-1870-paper-credits-boole-not-ancients-for-mechanizable-logic]]
- [[claim-jevons-dog-as-mechanization-model-is-barrett-connell-interpretation]]