groundwork, namely, human happiness,
depending on a life in accordance with virtue.

_Heraclides_ Ponticus, as he is usually called, was, as his name denotes,
a native of Pontus. He migrated to Athens, where he became a disciple of
Plato, who, while absent in Sicily, entrusted him with the care of his
school.

_Speusippus_ was the nephew of Plato, and succeeded him as President of
the Academy; but he continued so but a short time, and, within eight years
of the death of Plato, he died at Athens, B.C. 339. He refused to
recognise _the Good_ as the ultimate principle; but, going back to the
older theologians, maintained that the origin of the universe was to be
set down indeed as a cause of the Good and Perfect, but was not the Good
and Perfect itself; for that was the result of generated existence or
development, just as plants are of the seeds. When, with the Pythagoreans,
he reckoned _the One_ in the series of good things, he probably thought of
it only in opposition to _the Manifold_, and wished to point out that it
is from _the One_ that _the Good_ is to be derived. He appears, however,
(see De Nat. Deor. i. 13,) to have attributed vital activity to the
primordial unity, as inseparably belonging to it.

_Theophrastus_ was a native of Eresus, from whence he migrated to Athens,
where he became a follower of Plato, and afterwards of Aristotle, by whom,
when he quitted Athens for Chalcis, he was designated as his successor in
the presidency of the Lyceum; while in this position, he is said to have
had two thousand disciples, and among them the comic poet Menander. When,
B.C. 305, the philosophers were banished from Athens, he also left the
city, but returned the next year on the repeal of the law. He lived to a
great age, though the date of his birth is not certainly known.

He was a very voluminous writer on many subjects, but directed his chief
attention to continuing the researches into natural history which had been
begun by Aristotle. As, however, only a few fragments of his works have
come down to us, and these in a very corrupt state, we know but little
what peculiar views he entertained; though we learn from Cicero (De Inv.
i. 42-50) that he departed a good deal from the doctrines of Aristotle in
his principles of ethics, and also in his metaphysical and theological
speculations; and Cicero (De Nat. Deor. i. 13) complains that he did not
express himself with precision or with consistency about the Deity; and in