truth in the abstract is hardly won, and only by use familiarized to the
mind. Examples are akin to analogies, and have a reflex influence on
thought; they people the vacant mind, and may often originate new
directions of enquiry. Plato seems to be conscious of the suggestiveness
of imagery; the general analogy of the arts is constantly employed by him
as well as the comparison of particular arts--weaving, the refining of
gold, the learning to read, music, statuary, painting, medicine, the art of
the pilot--all of which occur in this dialogue alone: though he is also
aware that 'comparisons are slippery things,' and may often give a false
clearness to ideas. We shall find, in the Philebus, a division of sciences
into practical and speculative, and into more or less speculative: here we
have the idea of master-arts, or sciences which control inferior ones.
Besides the supreme science of dialectic, 'which will forget us, if we
forget her,' another master-science for the first time appears in view--the
science of government, which fixes the limits of all the rest. This
conception of the political or royal science as, from another point of
view, the science of sciences, which holds sway over the rest, is not
originally found in Aristotle, but in Plato.

The doctrine that virtue and art are in a mean, which is familiarized to us
by the study of the Nicomachean Ethics, is also first distinctly asserted
in the Statesman of Plato. The too much and the too little are in restless
motion: they must be fixed by a mean, which is also a standard external to
them. The art of measuring or finding a mean between excess and defect,
like the principle of division in the Phaedrus, receives a particular
application to the art of discourse. The excessive length of a discourse
may be blamed; but who can say what is excess, unless he is furnished with
a measure or standard? Measure is the life of the arts, and may some day
be discovered to be the single ultimate principle in which all the sciences
are contained. Other forms of thought may be noted--the distinction