The main doctrines to which the school remained constant throughout are concerned with cosmic
determinism and human freedom. Zeno believed that there is no such thing as chance, and that the
course of nature is rigidly determined by natural laws. Originally there was only fire; then the
other elements--air, water, earth, in that order--gradually emerged. But sooner or later there will be
a cosmic conflagration, and all will again become fire. This, according to most Stoics, is not a
final consummation, like the end of the world in Christian doctrine, but only the conclusion of a
cycle; the whole process will be repeated endlessly. Everything that happens has happened before,
and will happen again, not once, but countless times.
So far, the doctrine might seem cheerless, and in no respect more comforting than ordinary
materialism such as that of Democritus. But this was only one aspect of it. The course of nature, in
Stoicism as in eighteenth-century theology, was ordained by a Lawgiver who was also a
beneficent Providence. Down to the smallest detail, the whole was designed to secure certain ends
by natural means. These ends, except in so far as they concern gods and daemons, are to be found
in the life of man. Everything has a purpose connected with human beings. Some animals are
good to eat, some afford tests of courage; even bed bugs are useful, since they help us to wake in
the morning and not lie in bed too long. The supreme Power is called sometimes God, sometimes
Zeus. Seneca distinguished this Zeus from the object of popular belief, who was also real, but
subordinate.
God is not separate from the world; He is the soul of the world, and each of us contains a part of
the Divine Fire. All things are parts of one single system, which is called Nature; the individual
life is good when it is in harmony with Nature. In one sense, every life is in harmony with Nature,
since it is such as Nature's laws have caused it to be; but in another sense a human life is only in
harmony with Nature when the individual will is directed to ends which are among those of
Nature. Virtue consists in a will which is in agreement with Nature. The wicked, though perforce
they obey God's law, do so involuntarily; in the simile of Cleanthes, they are like a dog tied to a
cart, and compelled to go wherever it goes.
In the life of an individual man, virtue is the sole good; such things as health, happiness,
possessions, are of no account. Since virtue resides in the will, everything really good or bad in a
man's life depends only