Natural man is the animal man ego driven that knows only from sensed materiality.
"The ego man, little above the beasts, operating by sense and animal drives. The natural man does not know right and wrong.
"It is true there is a wisdom higher than the natural man. For the natural man is superstitious, bigoted, overbearing, proud, vain, full of cunning deceit and all the passions of the beast. He is very religious under some circumstances: fear of death for instance; bold when there is no danger and only kept in check by fear. This is the religious man, but this is not the religion or wisdom of the wise. All religion is of man and the trouble lies not in the religion or belief, but in the separation of opinions from the truth." [Quimby, The Complete Writing, Volume I, What is the Relation of God to Man]
"Every man has two selves, one acknowledged by the natural man, the other by the spiritual man." Quimby
"I have two identities, one in matter and the other out of matter, one can be seen and felt by the natural man and the other can feel and see the sick man's identity, which to him is not visible to his natural man.
What is a Clairvoyant (psychic) person?
It is being conscious of his own existence as a living, thinking, seeing, intelligent creature. And this is not seen by the natural man.
Then what is the natural man?
He is the shadow of the Clairvoyant, neither are conscious of the existence of both at the same time.
Why do you speak of two when one is only a shadow?
The Clairvoyant is like a man who is just where he thinks he is; The natural man is governed by a belief. Reason does not enter into the combination of the Clairvoyant." Quimby
“I will now tell you where I am and how I am leading you along. You are in the old world or testament. I am in the new world or testament, not P. P. Quimby but this truth. It is the light that lighteth everyone that cometh into this world and to make you understand it, it takes upon itself flesh and blood. So when it speaks, it speaks not as man speaks, but it speaks the truth, not opinions. The natural man is opinion, not wisdom; the scientific man is not flesh and blood but wisdom. And where wisdom is recognized by the natural man, then the natural man is not far from the kingdom of heaven. To gain the kingdom of heaven is to gain Science. There are many kinds of science, but they are all from one great wisdom. And science is the name of that particular application of wisdom to a particular phenomenon. Phineas Parkhurst Quimby
See Also
Ego
Ignorance
Mental Being
Science
Son of God
Son of Man
Superstition
Wisdom
See Wilhelm Reich's book "Be Still Little Man".