  Like Socrates, his philosophical model, and Carneades, who carried forward his skepticism in the 2nd c. BCE, Arcesilaus did not write any philosophical works. His arguments were initially preserved by his students—including Pythodorus, who wrote up some of them, and Lakydes, his successor as scholarch—and in the work of his opponents, most notably, the Stoic Chrysippus, whose reformulation of Stoicism was prompted by Arcesilaus’ criticisms of the views of the first generation of Stoics. But Arcesilaus’ arguments were later overlaid by Carneadean elaborations and subsumed into the general Academic and anti-Academic traditions; so it is only through those later traditions that we know about them. Our knowledge of his work depends on scraps from the biographical tradition (preserved in Diogenes Laertius and Philodemus) and brief general reports from later skeptical writers—Cicero and Sextus Empiricus and Plutarch—and their opponents—Antiochus and Numenius (preserved in Cicero and Eusebius respectively). But since these offer incompatible interpretations of Arcesilaus’ philosophical position, reflecting the writers’ distinctive views about later developments in the skeptical Academy, the precise nature of his skepticism remains controversial.