III.

Principles

Stoicism was the most influential philosophy in the Roman Empire during the period preceding the rise of Christianity. The Stoics, like the Epicureans, emphasized ethics as the main field of knowledge, but they also developed theories of logic and natural science to support their ethical doctrines. Their most important contribution to logic was the discovery of the hypothetical syllogism. They held that all reality is material, but that matter proper, which is passive, is to be distinguished from the animating or active principle, Logos, which they conceived as both the divine reason and as simply a finer kind of material entity, an all-pervading breath or fire, such as the Greek philosopher Heraclitus had supposed the cosmic principle to be. According to them the human soul is a manifestation of the Logos. Living according to nature or reason, they held, is living in conformity with the divine order of the universe. The importance of this view is seen in the part that Stoicism played in developing a theory of natural law that powerfully affected Roman jurisprudence.

The foundation of Stoic ethics is the principle, proclaimed earlier by the Cynics, that good lies not in external objects, but in the state of the soul itself, in the wisdom and restraint by which a person is delivered from the passions and desires that perturb the ordinary life. The four cardinal virtues of the Stoic philosophy are wisdom, courage, justice, and temperance, a classification derived from the teachings of Plato.

A distinctive feature of Stoicism is its cosmopolitanism. All people are manifestations of the one universal spirit and should, according to the Stoics, live in brotherly love and readily help one another. They held that external differences such as rank and wealth are of no importance in social relationships. Thus, before the rise of Christianity, Stoics recognized and advocated the brotherhood of humanity and the natural equality of all human beings.