The ambition of the present study is a limited one: to explain the use of the expression őσον ἐπί τῷ λóγῳ (hereafter ο∈τλ) in Sextus Empiricus. As it stands, that is to say with no addition of any kind, it does not occur frequently in his work: only on four occasions in all, PH 1.20, 227, III.48 and 72. On the other hand, the general formula őσοτ ἐπί + dative is often to be found not only in Sextus but also in other authors, most of them relatively late. Its general meaning could be expressed provisionally as follows: őσον ἐπί τῷ Ξ = ‘insofar as X is concerned’, ‘insofar as it is a matter of X’. This sense is particularly clear in reflexive uses of the expression, such as őσον ἐφ ἑαντῷ = ‘insofar as it is in him’, ‘insofar as it depends upon him’. But what is the meaning of λóγος in ο∈τλ? That is the question.

The reason why this formula seems to merit examination is above all because its meaning is so obscure where it first appears in PH, at 1.20, which describes a crucial aspect of the Sceptic attitude. To clarify our ideas, let me first suggest a provisional and incomplete translation of this passage. Sextus is replying to those who accuse the Sceptics of ‘suppressing the phenomena’ (ἀναιρεῖ τὰ φαινόμενα).