Before I begin an examination of sceptical arguments, I should perhaps say a few words about the term ‘scepticism’ itself. ‘Scepticism’, as I propose to use the word, may be characterized by two features: a thesis, viz. that nothing can be known, and a recommendation, viz. that one should suspend judgement on all matters. These two are logically independent of each other, since the thesis is not sufficient to justify the recommendation. Both are susceptible of different interpretations, so that they do not determine the details of a sceptical philosophy. I think it would be fair to say that in modern times the thesis has been the more prominent feature, while the ancients seem to have considered the recommendation as equally important. In this paper I will be mainly concerned with the recommendation, i.e. with epochē, though the thesis will also come up in the discussion of the sceptics' defence of their position. However, its credentials will not concern us here. I shall start with a problem of interpretation that arises out of the tradition about Carneades. Next, I will discuss the respective replies of Arcesilaus and Carneades to two (Stoic) arguments against scepticism, as examples of two different ways of defending the sceptic position. Finally, I will return to the first problem to see whether the investigation of Carneades' way of arguing can shed some light on it.