Note 54 — Chapter V · LOGIC OF THE STOICS.

The latter tendency will alone explain the care and precision which the Stoics devoted to studying the forms and rules which govern intellectual processes. Attention to this branch of study may be noticed in Zeno and his immediate successors at the first separation of Stoicism from Cynicism.54 Aristo is the only Stoic who is opposed to it, his whole habit of mind being purely that of a Cynic. In Chrysippus it attained its greatest development, and by Chrysippus the formal logic of the Stoics reached scientific completeness. In later times, when Stoicism reverted more nearly to its original Cynic type, and appealed directly to the immediate suggestions of the mind, it lost its interest in logic, as may be observed in Musonius, Epictetus, and others. For the present, however, let it suffice to consider the logic of Chrysippus, as far as that is known to us.