tus, but were modified by him in a manner subservient
and contributory to his ethical scheme. To that scheme it was essential
that those celestial, atmospheric, or terrestrial phenomena that the
public around him ascribed to the agency and purposes of the gods,
should be understood as being produced by physical causes. An eclipse,
an earthquake, a storm, a shipwreck, unusual rain or drought, a good or
a bad harvest--and not merely these, but many other occurrences far
smaller and more unimportant, as we may see by the eighteenth chapter
of the Characters of Theophrastus--were then regarded as visitations of
the gods, requiring to be interpreted by recognized prophets, and to be
appeased by ceremonial expiations. When once a man became convinced
that all these phenomena proceeded from physical agencies, a host of
terrors and anxieties would disappear from the mind; and this Epicurus
asserted to be the beneficent effect and real recommendation of
physical philosophy. He took little or no thought for scientific
curiosity as a motive _per se_, which both Democritus and Aristotle put
so much in the foreground.

Epicurus adopted the atomistic scheme of Democritus, but with some
important variations. He conceived that the atoms all moved with equal
velocity in the downward direction of gravity. But it occurred to him
that upon this hypothesis there could never occur any collisions or
combinations of the atoms--nothing but continued and unchangeable
parallel lines. Accordingly, he modified it by saying that the line of
descent was not exactly rectilinear, but that each atom deflected a
little from the straight line, and each in its own direction and
degree; so that it became possible to assume collisions, resiliences,
adhesions, combinations, among them, as it had been possible under the
variety of original movements ascribed to them by Democritus. The
opponents of Epicurus derided this auxiliary hypothesis; they affirmed
that he invented the individual deflection of each atom, without
assigning any cause, and only because he was perplexed by the mystery
of man's _free-will_. But Epicurus was not more open to attack on this
ground than other physical philosophers. Most of them (except perhaps
the most consistent of the Stoic fatalists) believed that some among
the phenomena of the universe occurred in regular and predictable
sequence, while others were essentially irregular and unpredictable;
each philosopher devised his hypoth