unity. That it is by virtue of this principle that every-
thing in the universe exists, is the teaching of Heracleitus.
All things contain their own opposites within them. In the
struggle and antagonism between hostile principles consists
their life, their being, their very existence. At the heart of
things is conflict. If there were no conflict in a thing, it
would cease to exist. This idea is expressed by Heraclei-
tus in a variety of ways. “Strife,” he says, “is the father of
all things.” “The one, sundering from itself, coalesces with
itself, like the harmony of the bow and the lyre.” “God is
day and night, summer and winter, war and peace, satiety
and hunger.” “Join together whole and unwhole, congru-
ous and incongruous, accordant and discordant, then comes
from one all and from all one.” In this sense, too, he cen-
sures Homer for having prayed that strife might cease from
among gods and men. If such a prayer were granted, the
universe itself would pass away.
{78}
Side by side with this metaphysic, Heracleitus lays down a
theory of physics. All things are composed of fire. “This
world,” he says, “neither one of the gods nor of the human
race has made; but it is, it was, and ever shall be, an eter-
nally living fire.” All comes from fire, and to fire all returns.
“All things are exchanged for fire and fire for all, as wares
for gold and gold for wares.” Thus there is only one ul-
timate kind of matter, fire, and all other forms of matter
are merely modifications and variations of fire. It is clear
for what reason Heracleitus enunciated this principle. It is
an exact physical parallel to the metaphysical principle of
Becoming. Fire is the most mutable of the elements. It
does not remain the same from one moment to another. It
is continually taking up matter in the form of fuel, and giv-
ing off equivalent matter in the form of smoke and vapour.
The primal fire, according to Heracleitus, transmutes itself
into air, air into water, and water into earth. This he calls
“the downward path.” To it corresponds “the upward path,”
the transmutation of earth into water, water to air, and air
to fire. All transformation takes place in this regular or-
der, and therefore, says Heracleitus, “the upward and the
downward path are one.”Fire is further specially identified with life and reason. It
is the rational element in things. The more fire there is,
the more life, the more movement. The more dark and
heavy materials there are, the more death, cold, and not-
being. The soul, accordingly, is fire, and like all other fires it
continually burns itself out and needs replenishment. This
it obtains, through the senses and the breath, from the
common life and reason of the {79} world, that is, from
the surrounding and all-pervading fire. In this we live and
move and have our being. No man has a separate soul of
his own. It is merely part of the one universal soul-fire.
Hence if communication with this is cut off, man becomes
irrational and finally dies. Sleep is the half-way house to
death. In sleep the passages of the senses are stopped up,
and the outer fire reaches us only through breath. Hence
in sleep we become irrational and senseless, turning aside
from the common life of the world, each to a private world
of his own. Heracleitus taught also the doctrine of periodic
world-cycles. The world forms itself out of fire, and by
conflagration passes back to the primitive fire.