In order to master this method of thought, you must understand above all that the things are only so-called things, but are in reality qualities of the universe, in other words, relative things or predicates of the absolute. You will then understand, that our thought has a right to make one thing as well as six of a chair, its back, its seat, and its four legs. You will recognize that the five senses of Aristotle are not an eternal truth, but a classification, which is eternally variable. Distinguishing means classifying. I know very well that I am making a bold statement here, and that it is not easy to justify it. For this reason you must not expect that I can make my meaning clear in a few sentences. It is not only the general prejudice which prevents this by making a most mysterious and miraculous thing of the intellectual function, but also the fact that this thing is still very obscure, although it has become clearer and clearer in the course of time. The freethinking pastor Hironymi writes on this point: "The most prominent naturalists of the present, such as Dubois-Reymond, who are at the same time thinkers, admit that they do not know what feeling, life, consciousness, are, and how they arise. And this ignorance is far more valuable for truth and religion than the alleged knowledge. Let us, therefore, continue in the devotion with which we have hitherto admired the universe without understanding it. The higher existence, the consciousness, has not been explained, it has remained a miracle, the only lasting, absolute, miracle." Thus speaks the preacher who is a know-nothing by nature and makes a business of admiring and wondering, while we are interested in understanding and knowing. We wish to fathom the mystery, and hence I may write still more letters on logic and you may study some more. I shall try to demonstrate by a trivial example, how it is that understanding or distinguishing is based on classification. Take it that you awake at early dawn and notice in a corner of your bed room something uncouth and moving which you cannot clearly distinguish. To know that a phenomenon appears is not enough because the term phenomenon applies to everything, natural and unnatural things, good and evil spirits. Even if you are sufficiently enlightened to know that the thing in question must be something natural, still this explains very little, for the term "nature" again means everything. But you understand or recognize more when you ascertain that the uncouth thing is dead or alive, wall paper or garment, man or animal. You will notice that in this intellectual enlightenment it is simply a matter of classification, of the head under which the mystery should be classed. To classify the phenomena of truth and life, means to understand, to use the intellect, to enlighten the brain.