important variations
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 hypothesis, and recognized some
fundamental principle, to explain the first class of phenomena as well
as the second. Plato admitted an invincible Erratic necessity;
Aristotle introduced Chance and Spontaneity; Democritus multiplied
indefinitely the varieties of atomic movements. The hypothetical
deflexion alleged by Epicurus was his way, not more unwarranted than
the others, of providing a fundamental principle for the unpredictable
phenomena of the universe. Among these are the mental (including the
volitional) manifestations of men and animals; but there are many
others besides; and there is no ground for believing that the mystery
of free-will was peculiarly present to his mind. The movements of a man
or animal are not exclusively subject to gravitation and other general
laws; they are partly governed by mental impulses and by forces of the
organism, intrinsic and peculiar to himself, unseen and unfelt by
others. For these, in common with many other untraceable phenomena in
the material world, Epicurus provides a principle in the supplementary
hypothesis of deflexion. He rejected the fatalism contained in the
theories of some of the Stoics, and admitted a limited range of empire
to chance, or irregularity. But he maintained that the will, far from
being among the phenomena essentially irregular, is under the influence
of motives; for no man can insist more strenuously than he does (see
the Letter to Menoecens) on the complete power of philosophy,--if the
student could be made to feel its necessity and desire the attainment
of it, so as to meditate and engrain within himself sound views about
the gods, death, and human life generally,--to mould our volitions and
character in a manner conformable to the exigencies of virtue and
happiness.
