arts and sciences, of the one, of the good, of the all:--this is the way
along which Plato is leading us in his later dialogues. In its higher
signification it was the knowledge, not of men, but of gods, perfect and
all sufficing:--like other ideals always passing out of sight, and
nevertheless present to the mind of Aristotle as well as Plato, and the
reality to which they were both tending. For Aristotle as well as Plato
would in modern phraseology have been termed a mystic; and like him would
have defined the higher philosophy to be 'Knowledge of being or essence,'--
words to which in our own day we have a difficulty in attaching a meaning.

Yet, in spite of Plato and his followers, mankind have again and again
returned to a sensational philosophy. As to some of the early thinkers,
amid the fleetings of sensible objects, ideas alone seemed to be fixed, so
to a later generation amid the fluctuation of philosophical opinions the
only fixed points appeared to be outward objects. Any pretence of
knowledge which went beyond them implied logical processes, of the
correctness of which they had no assurance and which at best were only
probable. The mind, tired of wandering, sought to rest on firm ground;
when the idols of philosophy and language were stripped off, the perception
of outward objects alone remained. The ancient Epicureans never asked
whether the comparison of these with one another did not involve principles
of another kind which were above and beyond them. In like manner the
modern inductive philosophy forgot to enquire into the meaning of
experience, and did not attempt to form a conception of outward objects
apart from the mind, or of the mind apart from them. Soon objects of sense
were merged in sensations and feelings, but feelings and sensations were
still unanalyzed. At last we return to the doctrine attributed by Plato to
Protagoras, that the mind is only a succession of momentary perceptions.
At this point the modern philosophy of experience forms an alliance with
ancient scepticism.