hing can be produced from nothing_, we shall
have a more accurate perception of that of which we are in search, and
shall understand whence each individual thing is generated, and how all
things are done without the agency of the gods."--Lucretius, "On the
Nature of Things," bk. i. l. 145-150.]

Physics and Psychology are thus the only studies which Epicurus would
tolerate as "conducive to the happiness of man." The pursuit of truth
for its own sake was useless. Dialectics, which distinguish the true
from the false, the good from the bad, on _a priori_ grounds, must be
banished as an unnecessary toil, which yields no enjoyment. Theology
must be cancelled entirely, because it fosters superstitious fears. The
idea of God's taking knowledge of, disapproving, condemning, punishing
the evil conduct of men, is an unpleasant thought. Physics and
Psychology are the most useful, because the most "agreeable," the most
"comfortable" sciences.

EPICUREAN PHYSICS.

In his physical theories Epicurus followed Leucippus and Democritus. He
expounds these theories in his letters to Herodotus and Pythocles, which
are preserved in Diogenes Laertius.[785] We shall be guided mainly by
his own statements, and when his meaning is obscure, or his exposition
is incomplete, we shall avail ourselves of the more elaborate statements
of Lucretius,[786] who is uniformly faithful to the doctrine of
Epicurus, and universally regarded as its best expounder.

The fundamental principle of his philosophy is the ancient maxim--"_de
nihilo nihil, in nihilum nil fosse reverti_;" but instead of employing
this maxim in the sense in which it is used by Parmenides, Anaxagoras,
Empedocles, and others, to prove there must be something self-existent
and eternal, or in other words, "that nothing which once was not can
ever of itself come into being," he uses it to disprove a divine
creation, and even presents the maxim in an altered form--viz., "nothing
is ever _divinely_ generated from nothing;"[787] and he thence concludes
that the world was by no means made for us by _divine_ power.[788]
Nature is eternal. "The universal whole always was such as it now is,
and always will be such." "The universe also is infinite, for that which
is finite has a limit, but the universe has no limit."[789]

[Footnote 785: "Lives of the Philosophers," bk. x.]

[Footnote 786: "De Natura Rerum."]

[Footnote 787: Lucretius, "On the Nature of Things," bk. i.]

[Footnote 788: Ibid