Ancient philosophy a new history of western philosophy volume 1 (new history of western philosophy) ( PDFDrive ) 196

EPISTEMOLOGY Academic Scepticism It is not surprising that Stoic epistemology should be challenged from a sceptical angle It was surprising, however, that the challenge should come from the Academy, from the heirs of Plato Surely the Platonic corpus contains some of the most dogmatic philosophy ever to be devised The leaders of the later Academy, however, Arcesilaus and his successor, Carneades, traced their ancestry further back They appealed to Socrates, whose question and answer technique so famously punctured false claims to knowledge (Cicero, Fin 2) Socrates himself claimed no philosophical knowledge, and left no philosophical writings; and Arcesilaus and Carneades followed him in both respects But they went further than Socrates in commending a much more radical scepticism: a suspension of belief not only on philosophical but also on the most everyday topics Though Arcesilaus and Carneades left no writings, we are reasonably well informed about their philosophical teachings because Cicero, who had been taught by Carneades’ pupil Philo, was much attracted to Academic Scepticism, and left a lively account of the to and fro of sceptical debate in his Academica From him and other sources we learn that the Academics presented a battery of arguments to show that there could be no infallible impressions There is no true impression arising from sensation that cannot be paired with another impression, indistinguishable from it, which is non-cognitive But if two impressions are indistinguishable, it cannot be the case that one of them is cognitive and the other not Therefore no impression, even if true, is cognitive To illustrate this argument, consider the case of identical twins, Publius Geminus and Quintus Geminus If someone looking at Publius thinks he is looking at Quintus, he has an impression that corresponds in every detail to the one he would have if he were in fact looking at Quintus Hence, his impression is not a cognitive one: it does not answer to the Wnal clause of Zeno’s deWnition: ‘of such a kind as could not arise from what is not’ (Cicero, Acad 83–5) In reply, the Stoics seem to have denied the possibility of any pair of objects resembling each other in every respect They propounded the thesis later known as the identity of indiscernibles: no two grains of sand, no two wisps of hair, were totally alike The Academics complained that the thesis 173