I’ve got to the point in the Cambridge Companion to the Stoics (chapter 6) where one of the authors, Keimpe Algra, tackles the thorny issue of Stoic theology. I say thorny not because there is anything too peculiar about the topic per se, but because of course I will have at some point to address it from a secular, non-theistic perspective, in my quest for updating Stoicism to the 21st century.
(Incidentally, as I’ve said before, one of the things I find attractive about modern Stoicism is that it has a big metaphysical tent, capable of accommodating theists, pantheists, agnostics and atheists, so long as they share the Stoic commitment to cultivating moral virtue as essential to a eudaimonic life.)
I am reading William B. Irvine’s superb A Guide to the Good Life: The Ancient Art of Stoic Joy, and early on in the book he begins to tackle the issue of whether embracing Stoicism requires a belief in a supreme being. While Stoicism is a philosophy, not a religion, some of the Stoics – especially Epictetus – do often refer to “Zeus,” understood not as the familiar Olympian god, but as similar to the God of the Judeo-Christian-Islamic tradition (though with some interesting differences).
At any rate, I think, as does Irvine, that belief in a supreme being is not necessary for Stoicism, and that it is even questionable the degree to which the ancient Stoics themselves thought it necessary. Below is a short extracts from the first time in the book in which Irvine discusses the issue, promising to return to it in greater depth later on: