Deus sive Natura -- God or Nature -- was Spinoza's was of trying to avoid the atheist label, even though by all accounts, that's exactly was he was. He used God as a euphemism for the universe, which is why it was rather clever of Einstein, upon being asked if he believed in the deity, to reply, "I believe in Spinoza's God."

Actually, there's an interesting sub-category of string theory that's known for its Spinozist bent on how the cosmos works.