Works
- Stoic propositional logic (the connectives and the five indemonstrable argument forms), 3rd century BCE
In Thinking Tools
Known for
The third head of the Stoic school, who built logic on propositions where Aristotle had built it on terms. He separated simple from compound propositions, defined the connectives, and set out five basic argument forms, among them the ones now called modus ponens and modus tollens.
Caveat: None of his works survive whole; his logic is known from fragments and later reports, chiefly Diogenes Laertius.