In separating philosophy and theology, Spinoza mounts a kind of historicist critique of the Bible; its authors are bound by the assumptions of their time and culture. Besides that, the Bible and philosophy are completely different in method and style; the Bible is narrative, and its truth depends on the reliability of the narrator rather than the power of its arguments.

For an early historicist, Spinoza certainly gives philosophy an historical bye. He doesn’t even seem to consider that philosophy is a contingent human product, its distinction from myth and poetry is something with a history, and not written into the nature of some pure idea of “philosophy.” No wonder philosophy comes off looking stable and sure, while theology looks a mess.