To attain Final Participation is simply to return to a child's basic understanding of the world as being really full of alive and conscious beings - but this time in full awareness that we ourselves, by our thinking, are participating in the knowing of reality.
In Original Participation the child perceives (sees, hears, feels) the
world to be really alive and conscious; in Final Participation we think
and we know that the world really is alive and conscious; and that we
have participated in making it so.
This Participation is indeed Final because it is the truth; it is the divine way of being.