ALL that exists or can exist in this or any other universe can be rendered into terms of consciousness; there is nothing that cannot be known. This knowing need not be always a mental knowledge. For the greater part of existence is either above or below mind, and mind can know only indirectly what is above or what is below it. But the one true and complete way of knowing is by direct knowledge.

It is only when we have seen both our Self and our outer nature as a whole, in the depths as well as on the surface, then we can acquire a true basis for knowledge.

Mental knowledge is of little use except sometimes as an introduction pointing towards the real knowledge which comes from a direct consciousness of things.
It is not a mental knowledge that is necessary, but a psychic perception or a direct perception in the consciousness. A mental knowledge can always be blinded by the tricks of the vital.

Mind itself is not enough; even its largest play of intelligence creates only a qualified half-light. A surface mental knowledge of the physical universe is a still more imperfect guide; for the thinking animal it might be enough, but not for a race of mental beings in labour of a spiritual evolution. Even the truth of physical things cannot be entirely known, nor can the right use of our material existence be discovered by physical Science and an outward knowledge alone or made possible by the mastery of physical and mechanical processes alone: to know, to use rightly we must go beyond the truth of physical phenomenon and process, we must know what is within and behind it. For we are not merely embodied minds; there is a spiritual being, a spiritual principle, a spiritual plane of Nature. Into that we have to heighten our force of consciousness, to widen by that still more largely, even universally and infinitely, our range of being and our field of action, to take up by that our lower life and use it for greater ends and on a larger plan, in the light of the spiritual truth of existence.

The consciousness of union with the Divine is for the spiritual seeker the supreme knowledge.

An inspired Knowledge sat enthroned within
Whose seconds illumined more than reason's years.