The "Son of Man" refers to the "psychological ego" in humans. It was also called the Man of Dust or First Man by St. Paul.
The Son of God refers to the "inner man," the holy spirit, the Christ, the son or reflection of God. (Your true SELF when not identified with the body and brain.)
The Son of God, or inner man, is what one is "born again" into when the psychological ego (first man, man of dust, outer man, etc.) is not identified with. This new life or born again life is called by many names; enlightenment, Satori, Nirvana, union with Tao, heaven, Kingdom of God, Eden, virtue, samadhi, God realization, etc., etc.
We are in training to be nobody special. And it is in that nobody specialness that we can be anybody. The the somebody-ness, the ego or separate mentality. (This condition is the real meaning of disease-dis-ease, ill-at ease.) But we have to start somewhere. It does seem that we have to be somebody before we can become "nobody." If we started out being nobody at the beginning of this incarnation, we probably wouldn't have made it this far. For it's that force of somebody-ness that develops the social and physical survival mechanisms. It is only now having evolved to this point, that we learn to put that somebody-ness, that whole survival kit which is called the ego, into perspective. It's very far out when we begin not to think or the thinking is going by and, "We're not identified with being the thinker." At first we really "think" we've lost something. It's a while before we can appreciate the peace that comes from the simplicity of no-mind, of just emptiness, of not having to be somebody all the time. We've been "somebody" long enough. We spend the first half of our lives becoming somebody. Now we can work on becoming "nobody" (no-body), which is really "somebody special." For when we become "nobody" there is no tension, no pretense, no one trying to be anyone or anything, and the "natural state of mind" (as consciousness, being, existence) shines through unobstructed. The natural state of the mind is love (non judgmental) which is not other than pure awareness. We've finally acknowledged who we really are. We've cleared away all of the mind trips that kept us being who we thought we were. We experience love for everyone we meet, we have compassion to let other people be as they need to be. For being nobody, there is nobody were not. (This is how to love thy neighbor as thy SELF – because on the inner spiritual level, thy neighbor is thy SELF.)
A problem cannot be solved by the same mind that created it.
Miester Eckhart, in his treatise on how everyone is an "aristocrat" or "royal person," he makes the distinction between the external person (the ego) and the inner person.
All virtue of the just and every work of the just is nothing other than the son- who is the new creation being born from the father. In the depths of our being, where justice and work are done, we work one and a new creation with God.
-Meister Eackhart, 94