Stoic Logic Stoic Logic by Benson Mates is a landmark study of the propositional logic developed by the early Stoic philosophers, including Zeno, Chrysippus, and their Megarian predecessors. Originally published in 1953 and reissued in 1961, the book presents a rigorous reconstruction of the Stoic logical system, its underlying semantic theory, and its historical sources. Mates draws upon ancient sources such as Sextus Empiricus, Diogenes Laertius, and Galen, and compares Stoic concepts with modern developments in formal logic, including those by Frege and Carnap. The book provides detailed analysis of the Stoics' unique theory of Lekta (sayables), their classification of arguments, and their views on necessity, implication, and propositional structure. This scholarly work remains an essential reference for anyone interested in the history of logic and Hellenistic philosophy. This book is important because it uncovers a largely overlooked chapter in the history of logic. Long before modern symbolic logic, the Stoics developed a propositional system with striking parallels to 20th-century logic. Benson Mates brings these ancient insights to light with scholarly precision, bridging classical philosophy and contemporary thought. Download the book here:

 Stoic Logic