The return of the soul to the One has nothing to do for Plotinus with movement in space and the final union can be attained while still in the body (though, for the human soul at least, he thinks that permanent union is only attainable when the soul has finally left the body). The process is one of interiorization, of turning away from the external world, of concentrating one’s powers inwardly instead of dissipating them outwardly, of rediscovering one’s true self by the most vigorous intellectual and moral discipline, and then waiting so prepared for the One to declare His presence, for the final illumination and union. The rediscovery of one’s true self is a return to Noûs; for, as we have seen, Plotinus teaches that we are more than soul, we are Noûs; and ‘we do not altogether come down’; the highest part of our selves remains in the world of Noûs even when we are embodied (it is our archetypal original, the individual Form of which our soul is a Logos). And, when we are Noûs, we can share in its self-transcendence and contemplate the One with that in our Noûs which is not Noûs, (V. 5. 7-8 — D (a), p. 71) though our experience of this highest state can only be a rare and fleeting one as long as we are handicapped by the body.
Of the final union it is better to leave Plotinus himself to speak. But there are two things about it which should be said to avoid misunderstanding. The first is that Plotinus insists that there is no short cut, no mysticism which does not demand moral and intellectual perfection. We must ascend to Noûs first, and it is only as Noûs, as a being perfect in wisdom and goodness, that union with the One is possible. This union transcends our intellectual and moral life because in it we ascend to the Source of intellect and goodness which is more than they are, but it is only possible because our intellectual and moral life has reached its perfection. We are ‘ carried out by the very surge of the wave of Noûs. (VI. 7. 36 — G (c),p. 158) It is the completion and confirmation, not the negation and destruction of all that we have done ourselves (as Plotinus would say; a Christian would say, that God has done in us) to bring our selves to perfection, to the fullest consciousness and activity. And, again, because it is as Noûs that we attain to union, it would seem that it is not Plotinus’s thought that our individual personalities are finally absorbed and disappear. It is true that in the union we rise above Noûs to a state in which there is no consciousness of difference from the One, in which there is no longer Seer and Seen, but only unity. But universal Noûs, of which we are then a part, exists continually in that state of union without prejudice to its proper life of intuitive thought and unity-in-diversity. There is never any suggestion in Plotinus that all things except the One are illusions or fleeting appearances.