ABSTRACT
Almost from the very beginning it is possible to speak of sceptical currents in Greek philosophy. Xenophanes can be called the father of Scepticism, and with some justification Heraclitus has been counted among its ancestors. But scepticism is many things. An important tradition in Greek thought considers intellectual cognition certain, yet is sceptical about the possibility of valid sense cognition. This ‘tradition’ includes such different names as Parmenides, Democritus, Plato and Aristotle. A typical ‘rationalist’ counter-attack against general scepticism is the Aristotelian argument: even if I have no certain knowledge that this is an x, I know what it means to be x.
