Note 141 — Chapter V · LOGIC OF THE STOICS.

D. Estimate of Stoic Logic. (1) Its shortcomings. In all these researches the Stoics were striving to find firm ground for a scientific process of proof. Great as was the value which they attached to such a process, they nevertheless admitted, as Aristotle had done before, that everything could not be proved. Here was their weak point. Instead, however, of strengthening this weak point by means of induction, and endeavouring to obtain a more complete theory of induction, they were content with conjectural data, sometimes self-evident, at other times depending for their truth on the truth of their inferences.141 Thus, their theory of method, like their theory of knowledge, ended by an ultimate appeal to what is directly certain.