At the top of the universe is Heaven. It is inhabited by God and those angels who did not rebel against him. The primary quality of Heaven is light. God is pure light of such quality that the angels must observe him through a cloud. The angels themselves are also a type of stunning, pure light but not comparable to the light of God because they give off colors. Raphael is described as being made of "colors dipt in Heaven" (283) in Book V. Milton's source for this Heaven of light is the first command of God in Genesis: "Let there be light, and there was light."
The name Milton uses for this light-filled Heaven is the Empyrean, which for classical authors was the indestructible realm of light or fire. Thus, when the war in Heaven occurs, it is between beings who are indestructible. God says that the rebellious angels can be annihilated, but exactly what he means is never clear. With that one exception, however, everything associated with Heaven or the Empyrean is eternal and indestructible.
Within Heaven, God sits at the top of a mountain on his eternal throne. He is shrouded in a cloudy mist because of the quality and intensity of the light he emanates. The Son is at his side. In orthodox Protestant theology, they are two parts of a tripartite whole — the Holy Spirit being the third. Each of these characters represents an aspect of God. God is the Father; pure reason and intellect, perfect unemotional justice. The Son is the more merciful side. He demonstrates pity, mercy, sacrifice, and hope. (The Holy Spirit is mentioned only in the prologues as the true Urania, Milton's muse.) In Milton's personal view, the Son and God are not the same. God created the Son who is so close to God that any distinction is imperceptible, even to angelic sensibilities. Theologically then, Milton was a Unitarian, though he never develops this viewpoint in Paradise Lost.
