ality and unity,
which were supposed to be joined and severed by love and hate,
some maintaining that this process was perpetually going on (e.g.
Heracleitus); others (e.g. Empedocles) that there was an alternation of
them. Of the Pythagoreans or of Anaxagoras he makes no distinct mention.
His chief opponents are, first, Eristics or Megarians; secondly, the
Materialists.

The picture which he gives of both these latter schools is indistinct;
and he appears reluctant to mention the names of their teachers. Nor can
we easily determine how much is to be assigned to the Cynics, how much
to the Megarians, or whether the 'repellent Materialists' (Theaet.)
are Cynics or Atomists, or represent some unknown phase of opinion at
Athens. To the Cynics and Antisthenes is commonly attributed, on the
authority of Aristotle, the denial of predication, while the Megarians
are said to have been Nominalists, asserting the One Good under many
names to be the true Being of Zeno and the Eleatics, and, like Zeno,
employing their negative dialectic in the refutation of opponents. But
the later Megarians also denied predication; and this tenet, which is
attributed to all of them by Simplicius, is certainly in accordance with
their over-refining philosophy. The 'tyros young and old,' of whom
Plato speaks, probably include both. At any rate, we shall be safer in
accepting the general description of them which he has given, and in not
attempting to draw a precise line between them.

Of these Eristics, whether Cynics or Megarians, several characteristics
are found in Plato:--

1. They pursue verbal oppositions; 2. they make reasoning impossible by
their over-accuracy in the use of language; 3. they deny predication;
4. they go from unity to plurality, without passing through the
intermediate stages; 5. they refuse to attribute motion or power to
Being; 6. they are the enemies of sense;--whether they are the 'friends
of ideas,' who carry on the polemic against sense, is uncertain;
probably under this remarkable expression Plato designates those who
more nearly approached himself, and may be criticizing an earlier form
of his own doctrines. We may observe (1) that he professes only to give
us a few opinions out of many which were at that time current in
Greece; (2) that he nowhere alludes to the ethical teaching of the
Cynics--unless the argument in the Protagoras, that the virtues are one
and not many, may be supposed to contain a reference to th