  Notwithstanding the sharp distinction between the temporal and the eternal realm, there are beings that share in both eternity and time. As Proclus notes in the corollary to Elem. Theol. § 55, “of the things which exist in time, some have a perpetual duration.” Thus the universe as a whole and the celestial spheres in it are both eternal and temporal. They are eternal because they never come to existence in time and never will cease to exist. But they are temporal because they possess their being only through a process of change in a sequence of moments. The same holds true for the psychic realm: all souls are immortal and indestructible; nevertheless, they are continually undergoing change. Therefore, as Proclus says, “‘perpetuity’ (aidiotês) is of two kinds, the one eternal (aiônion), the other in time; […] the one having its being concentrated in a simultaneous whole, the other diffused and unfolded in temporal extension (paratasis); the one entire in itself, the other composed of parts, each of which exists separately in a sequence of prior and posterior.” (Elem. Theol. § 55, trans. Dodds, modified).