the Epicurean; he differed also in his theology and his physics and
his metaphysics. Aristotle, as Shakespeare knew, thought young men
"unfit to hear moral philosophy". And yet it was a question--or
rather the question--of moral philosophy, the answer to which decided
the young man's opinions on all other points. The language which
Cicero sometimes uses about the seriousness of the choice made in
early life and how a young man gets entrammelled by a school before
he is really able to judge, reminds us of what we hear said nowadays
about the danger of a young man's taking orders before his opinions
are formed. To this it was replied that a young man only exercised
the right of private judgment in selecting the authority whom he
should follow, and, having once done that, trusted to him for all the
rest. With the analogue of this contention also we are familiar in
modern times. Cicero allows that there would be something in it, if
the selection of the true philosopher did not above all things
require the philosophic mind. But in those days it was probably the
case, as it is now, that, if a man did not form speculative opinions
in youth, the pressure of affairs would not leave him leisure to do
so later.

The life span of Zeno, the founder of Stoicism, was from B.C. 347 to
275. He did not begin teaching till 315, at the mature age of forty.
Aristotle had passed away in 322, and with him closed the great
constructive era of Greek thought. The Ionian philosophers had
speculated on the physical constitution of the universe, the
Pythagoreans on the mystical properties of numbers; Heraclitus had
propounded his philosophy of fire, Democritus and Leucippus had
struck out a rude form of the atomic theory, Socrates had raised
questions relating to man, Plato had discussed them with all the
freedom of the dialogue, while Aristotle had systematically worked