SEXTUS AND DESCARTES

In a ground-breaking paper, Myles Burnyeat brings into focus what is surely, from a contemporary standpoint, the most striking difference between the scepticism found in Sextus Empiricus' Outlines of Pyrrhonism and that which animates Descartes' Meditations: Sextus' failure to pose in full generality the sceptical problem concerning our knowledge of the external world. For while Sextus and Descartes both question our capacity for knowing the real natures of things, Descartes goes beyond this “essential” scepticism to pose an “existential” problem: how do we know that the external world even exists?

What accounts for this difference? A tempting answer, in part Burnyeat’s own, contrasts the practical concerns of Sextus with the theoretical orientation of Descartes. Pyrrhonian scepticism is a way of life: the sceptic lives adoxastos (conventionally rendered “without belief”), letting his actions be guided by natural capacities and acquired habits rather than reasoned judgements. Conceiving scepticism as a way of living in the world, Sextus can hardly doubt the world’s very existence. By contrast, Descartes treats scepticism as a mere methodological device, to be taken seriously only in the context of inquiries into “first philosophy,” a context in which all practical concerns are temporarily set aside. Freed from practical constraint, Descartes can push scepticism to an unprecedented extreme.