The publication in 1907 of the Berlin papyrus containing Sappho's poem τεθνάκην δʹ ⋯δόλως θέλω κτλ posed in the clearest possible form the problem, already highly controversial, of the metrical structure of the Glyconic and its associated metres; and many answers have been suggested to the question ‘What is the peculiar nature of the Glyconic line which permits of its being related to two types of line apparently constructed on quite different principles?’ What follows is an attempt to consider this problem once more, with reference to other simple types of line which seem to provide analogies for the process which I believe to have occurred.

The similes of the Sun, Line, and Cave in the Republic remain a reproach to Platonic scholarship because there is no agreement about them, though they are meant to illustrate. I propose to analyse the form of the argument, a clue that has never been properly weighed. The Greek theory and practice of analogia and diairesis give good evidence about the method that Plato adopted; if this usage were respected, the analogical argument would not be so loosely interpreted, and the double diairesis and proportion that the Line actually is could not be mistaken for a classification. I hope also to show that Plato's terminology is definite and consistent; here too ancient usage helps to establish his meaning.

In Professor Ferguson's renewed study (above, pp. 190–210) of these similes he has introduced a very detailed and careful analysis of Plato's analogies in order to explain and support his interpretation. He has also attacked the view which I put forward in 1932, and I should like to say something in defence of that view, not in any polemical spirit, but from a perhaps too obstinate belief that my reading of the passage does rest on solid foundations. I will not attempt any comprehensive discussion of Professor Ferguson's theories, either in their earlier or their present form, but merely try to indicate what seems to me the real issue between us.