^Tenets? It's a theory, not a philosophy!
His theory is that consciousness in humans evolved only around 3000 years ago, and that prior to this we functioned with bicameral minds, with one hemisphere of the brain issuing commands in the form of auditory and sometimes visual hallucinations, and the other hemisphere acting out those commands without any question.
Wow indeed, that ^there would explain all that we call religion.
Exactly, and that's a big part of his theory. Part of his literary evidence involves comparisons of gods in text 3000 years and older, such as Greek gods and Old Testament Yahweh, to gods in religious texts newer than 3000 years, showing how our understanding of and relationship to gods have changed.