Just as the faculty of thinking is innate in the child, and grows with its development, so mankind's faculty of thought grows and has hitherto expressed itself in a language which gave only instinctive conceptions of the composition of the human brain and of its functions. The construction of languages explains in a way the condition of the human mind which had only inadequate knowledge of itself so far. Those shortcomings of speech which I called slips of the tongue were not understood until sufficient progress had been made in the explanation of the process of thinking, and now these same shortcomings offer an excellent means of representing and demonstrating the results of enlightenment. The mind is to give to man a picture of the world, the language is the brush of the mind. It paints by its construction the universal relationship of all things referred to in the beginning of this chapter, and it does so in the following manner: It gives to each thing not only its own name, but also adds to it another indicating its family, and another indicating its race, another for the species, the genus, and finally a general name which proclaims that all things are parts of the one indivisible unit which is called world, existence, universe, cosmos. This diagrammatic construction of language furnishes us with an illustration of the graduated relationship of things and of the way in which the human race arrives at its knowledge, its perceptions or pictures. We said that philosophy is that endeavor which seeks to throw light on the process of human thought. This work has been rendered very difficult by the unavoidable misunderstanding of the universal relationship just mentioned. The transcendentalists insist above all that the process of thinking and its product, thought, should not be classed among ordinary physics, not as a part of physical nature, but as the creature of another nature which carries the mysterious name of metaphysics. That such a nature and such a science is neither possible nor real is proven by the construction of language which normally describes everything as being closely related and corroborates this by its abnormal shortcomings which we called slips of the tongue. The shortcomings of language which demonstrate the positive outcome of philosophy consist in occasionally giving insufficiently significant names to things belonging to a group in which the distinction between individuals, species, genera, and families is not clearly defined. It is not discernible, for instance, whether the term "cat" applies to a domestic cat or to a tiger, because that term is used for a large class of animals of which the domestic cat is the arch-type.