“The Platonic School is even more distinct in enunciating all this. The real selfhood was at the basis of all. Socrates therefore taught that he had a daimonion, a spiritual something which put him on the road to wisdom. He himself knew nothing, but this put him in the way to learn all. Plato followed him with a full investigation of the principles of being. There was an Agathon, Supreme God, who produced his own mind a paradeigma of all things. He taught that in man was “the immortal principle of the soul”, a mortal body, and a “separate mortal kind of soul”, which was placed in a separate receptacle of the body from the other; the immortal part was in the head, (Timaeus 19 and 20), the other in the trunk, (44).
Nothing is plainer than that Plato regarded the interior man as constituted of two parts – one always the same, formed of the same entity as Deity, and one mortal and corruptible. “Plato and Pythagoras”, says Plutarch, “distribute the soul into two parts, the rational (noëtic), and irrational (agnoia); that that part of the soul of man, which is rational, is eternal; for though it be not God, yet it is the product of an eternal deity, but that part of the soul, which is divested of reason, (agnoia), dies.”
“Man”, says Plutarch, “is compound; and they are mistaken who think him to be compounded of two parts only. For they imagine that the understanding is a part of the soul, but they err in this no less than those who make the soul to be a part of the body, for the understanding, (nous), as far exceeds of the soul, as the soul is better and diviner than the body. Now this composition of the soul, with the understanding, makes reason; and with the body, passion; of which the one is the beginning or principle of pleasure and pain, and the other of virtue and vice. Of these three parts conjoined and compacted together, the earth has given the body, the moon the soul, and the sun the understanding to the generation of man.
Now of the deaths we die, the one makes man two of three, and the other, one of, (out of), two. The former is in the region and jurisdiction of Demeter, whence the name given to the Mysteries, τελειν, resembled that given to death, τελευταν. The Athenians also heretofore called the deceased sacred to Demeter. As for the other death, it is in the moon or region of Persephoné. And as with the one terrestrial, so with the other the celestial Hermes doth dwell. This suddenly and with violence plucks the soul from the body; but Proserpina mildly and in a long time disjoins the understanding from the soul. For this reason, she is called Monogenes, only-begotten, or rather begetting one alone; for the better part of man becomes alone when it is separated by her. Now both, the one and the other, happens thus according to nature.
It is ordained by Faith that every soul, whether with or without understanding, when gone out of the body, should wander for a time, though not all for the same, in the region lying between the earth and the moon. For those that have been unjust and dissolute suffer there the punishment due to their offenses; but the good and virtuous are there detained till they are purified, and have, by expiation, purged out of them all the infections they might have contracted from the contagion of the body, as if from foul health, living in the mildest part of the air, called the Meadows of Hades, where they must remain for a certain prefixed and appointed time. And then, as if they were returning from a wandering pilgrimage or long exile into their country, they have a taste of joy, such as they principally receive who are initiated into Sacred Mysteries, mixed with trouble, admiration, and each one’s proper and peculiar hope.””
H. P. Blavatsky
The Mark Of God: Understanding Your "I AM Presence" 