302
PLATO
it about E until it passes through a point P of the circle such
that, if EP meets AB and AC produced in T, R, PT shall be
equal to ER. Then, since RE=PT, AD —AIT, where M is
the foot of the ordinate PAL
Therefore DT — A AT, and
AAI-.AD = DT-.A1T
— ED: PM,
whence PM . MA = ED. DA,
and APAI is the half of the required (isosceles) triangle.
Benecke criticizes at length the similar interpretation of the
passage given by E. F. August. So far, however, as his objec
tions relate to the translation of particular words in the
Greek text, they are, in my opinion, not well founded. 1 For
the rest, Benecke holds that, in view of the difficulty of the
problem which emerges, Plato is unlikely to have introduced
it in such an abrupt and casual way into the conversation
between Socrates and Meno. But the problem is only one
of the same nature as that of the finding of two mean
proportionals which was already a famous problem, and, as
regards the form of the allusion, it is to be noted that Plato
was fond of dark hints in things mathematical.
If the above interpretation is too difficult (which I, for one,
do not admit), Benecke’s is certainly too easy. He connects
his interpretation of the passage with the earlier passage
about the square of side 2 feet; according to him the problem
is, can an isosceles right-angled tri
angle equal to the said square be
inscribed in the given circle 1 ? This
is of course only possible if the
radius of the circle is 2 feet in length.
If AB, DE be two diameters at right
angles, the inscribed triangle is ADE;
the square ACDO formed by the radii
AO, 0D and the tangents at D, A
is then the ‘ applied ’ rectangle, and
the rectangle by which it falls short is also a square and equal
1 The main point of Benecke’s criticisms under this head has reference
to toiovtco )((Oj>La> oiav in the phrase iWe'nuiv rotovrco ^copt« OLOV * IV ovro to
TTapnr.Tafifvov y. He will have it that toiovtco olov cannot mean ‘ similar to ’,