The Stoic position in metaphysics is materialistic. Stoics held that all reality was material or physical stuff, but they took as their paradigm of a material thing a living organism . The Stoic position in epistemology is rationalistic. As the Universe is a vast living organism directed by a universal mind or logos , one can understand the nature of reality when one can understand how The Logos directs the universe . Thus what we know of our own mind or soul , by analogy is true of the universe as a whole .
Stoicism is a deterministic theory.
The Logos, as rational, directs the universe for a purpose . Assuming the universe to be eternal, Stoics concluded that The Logos was i mmortal , hence divine , hence perfect . From this it followed that The Logos directs all things that happen in the universe for the reason that it is best that it happen that way . Therefore, the Stoics reached the conclusion that we live in a deterministic universe . The Stoic position in ethics is a deontological theory.