Nature is much bigger than what a man can perceive through the ordinary senses of the body. The hidden aspects of nature consist of finer matter and forces that interpenetrate and exists together with the physical’
There is no unbridgeable gulf separating the finer aspects of nature from its gross aspects. The finer aspects of nature are not perceptible to man, but they are nevertheless continuous with the gross aspects. They are not remote, and yet they are inaccessible to his consciousness.
This is due to the fact that his consciousness is functioning through the physical senses which are not adapted for perceiving these aspects of nature which are finer than the gross aspects. He is unconscious of these "inner planes," just as a deaf man is unconscious of sounds; and naturally he cannot also deal with them consciously.
The pathway of a man through the divisions of nature's hidden part is called gnosis; the object of the various systems of religious ceremony and doctrine is to prepare for it. Gnosis is the internal but actual pathway inside a human being. Though it is not exactly like a material road, it is distinctly perceptible to the internal eye of a real mystic or gnostic, who actually has the experience of travelling along it.
(Treasures- pp. 60-61, ed. Jane B. Haynes)