The second assumption, which the Neoplatonists shared with the Stoics and the Hermetists (an influential group of Egyptian religious thinkers that predate the rise of Neoplatonism), was that reality, in all its cognitive and physical manifestations, depended on a highest principle which is unitary and singular. Neoplatonic philosophy is a strict form of principle-monism that strives to understand everything on the basis of a single cause that they considered divine, and indiscriminately referred to as “the First”, “the One”, or “the Good”. Since it is reasonable to assume, as the Neoplatonists did, that any efficient cause is ontologically prior to, and hence more real, than its effect, then, in the hierarchy of being, the first principle, whatever it is, cannot be less “real” than the phenomena it is supposed to explain. Given the veracity of the first assumption (the ontological priority of intelligence and consciousness), it follows at once that the first principle must be a principle of consciousness. In consequence, the fundamental challenge all Neoplatonists struggled to meet was essentially the following: How are we to understand and describe the emergence of the universe, with all its diverse phenomena, as the effect of a singular principle of consciousness? In particular—and in this regard Neoplatonism shares certain concerns with modern cosmology—how is it possible to understand the emergence of the physical, material universe from a singularity that is in every sense unlike this universe? Their answer to this question was entirely new, and went far beyond any prior cosmic aetiology, including that of Plato’s Timaeus, in elegance and sophistication.