1. A nice contrast with 276d, where the same situation, verbally echoed here, led to Euthydemus increasing the confusion, rather than trying to explain himself.

2. The shift from luck as something the expert has to something the expert’s protégé has is not important: Socrates’ point is that in either case good luck is a product of expertise.

3. Similarly, at Republic 340d-e, Thrasymachus is made to argue that a failure in skill is by definition not skill. The concept of skill does not in itself allow error.

4. Reading Öταν with the manuscripts.

5. ‘Happiness’ translates eudaimonia, for which there is really no satisfactory translation (see p. 25). It is whatever one takes to be the goal of life and to fulfil one’s nature – sensual pleasurefor some, for others contemplation, and so on. It is vague, then, in the same way as ‘success’ (see p. 327 n. 2), with which it is here taken to be synonymous.