coincidences of style is much increased when they are found side by side
with thoughts and expressions which can only have come from a great
original writer. The great excellence, not only of the whole, but even of
the parts of writings, is a strong proof of their genuineness--for
although the great writer may fall below, the forger or imitator cannot
rise much above himself. Whether we can attribute the worst parts of a
work to a forger and the best to a great writer,--as for example, in the
case of some of Shakespeare's plays,--depends upon the probability that
they have been interpolated, or have been the joint work of two writers;
and this can only be established either by express evidence or by a
comparison of other writings of the same class. If the interpolation or
double authorship of Greek writings in the time of Plato could be shown to
be common, then a question, perhaps insoluble, would arise, not whether
the whole, but whether parts of the Platonic dialogues are genuine, and,
if parts only, which parts. Hebrew prophecies and Homeric poems and Laws
of Manu may have grown together in early times, but there is no reason to
think that any of the dialogues of Plato is the result of a similar
process of accumulation. It is therefore rash to say with Oncken (Die
Staatslehre des Aristoteles) that the form in which Aristotle knew the
Laws of Plato must have been different from that in which they have come
down to us.

It must be admitted that these principles are difficult of application.
Yet a criticism may be worth making which rests only on probabilities or
impressions. Great disputes will arise about the merits of different
passages, about what is truly characteristic and original or trivial and
borrowed. Many have thought the Laws to be one of the greatest of Platonic
writings, while in the judgment of Mr. Grote they hardly rise above the
level of the forged epistles. The manner in which a writer would or would
not have written at a particular time of life must be acknowledged to be a