Our brain is supposed to solve the contradictions of nature. If it knows enough about itself to realize that it is not an exception from general nature, but a natural part of the same whole--although it calls itself "spirit"--then it also knows and must know that its clearness can differ but moderately from the general confusion, that the solution of the problem cannot differ materially from the problem itself. The contradictions are solved only by reasonable differentiation, only by the science of understanding which shows that extravagant differences are nothing but extravagant speculations. The human understanding inclines to exaggerations in its untrained state, and it is a relic of untrained habits to differentiate in an absolute manner the spiritual from the rest of nature, to make a too extravagant distinction between it and the physical body. It is the merit of philosophy to have given us a clear doctrine of the use of the intellect, and this doctrine culminates in the rule not to make exaggerated, but only graduated distinctions. For this purpose it is necessary to realize that there is only one being and that all other socalled beings are but minor expressions of the same general being, which we designate by the name of nature or universe. In consequence of the human bent to exaggeration, the human understanding has been regarded as a being of a different nature from that of natural beings which exist outside of the intellect. But it must be remembered that every part of nature is "another" individual piece of it, and, furthermore, that every other and different part is really nothing different but a uniform piece of the same general nature. The thing is mutual: The general nature exists only in its many individual parts, and these in their turn exist only in, with and by the general cosmic being. Nature which is divided by the human understanding into East and West, South and North, and into a hundred thousand other named parts, is yet an undivided whole of which we may say with certainty that it has as many innumerable beginnings and ends as it is without beginning and end, as it is the infinite itself. It is well known that there is nothing new under the sun. Nothing is created, nothing disappears, and yet there is a continuous change. The brain of man has a right and a left side, a top and a bottom, a front and a back part, an interior and an exterior. And the innermost of the brain again has two sides or qualities, a physical and a spiritual. They are so little divided that the term brain has two meanings, designating now the physical brain, now its mental functions. In speaking here exclusively of the mind, we tacitly assume its inseparable connection with the physical body.