There are three main reasons for thinking that I.23.6 and the excursus 88-118 were not written at the same time as 23.5 and the exposition of the aitiai in 24-87.(a) 23.5 is an emphatic full close, and the statement that the author has set out the alirla so that no one need ever be in doubt about them leads naturally into the exposition as it begins in 24. It is not simply that the removal of 23.6 would leave no visible gap in the text--this argument is rightly suspect: the point is that the alethestate prophasis makes a positive interruption, so that the thread needs to be picked up again with the aitiai of each side before we can go on to Epidamnos.