It is true that it sounds contradictory to say that the nature of a thing does not appear to the eye, but to the faculty of thought, and at the same time to imply that the opposite of appearance, nature, should appear. But we here refer to the nature of a thing as a phenomenon in the same way in which we referred to the mind as a perception of the senses, and we shall demonstrate further on that every being is a phenomenon, and every phenomenon is more or less of an essential thing. We have seen that the faculty of thought requires for its vital activity an object, or raw material. The effect of reasoning is seen in science, no matter whether we understand the term science in its narrow classical sense or in its broadest meaning of any kind of knowledge. The phenomena of sense perception constitute the general object or material of science. Sense perceptions arise from infinite circulation of matter. The universe and all things in it consist of transformations of matter which take place simultaneously and consecutively in space and time. The universe is in every place and at any time itself, new, and present for the first time. It arises and passes away, passes and arises under our very hands. Nothing remains the same, only the infinite change is constant, and even the change varies. Every particle of time and space brings new changes. It is true that the materialist believes in the permanency, eternity, indestructibility of matter. He teaches us that not the smallest particle of matter has ever been lost in the world, that matter simply changes its forms eternally, but that its nature lasts indestructibly through all eternity. And yet, in spite of all distinctions between matter itself and its perishable form, the materialist is on the other hand more inclined than any one else to dwell on the identity of matter and its forms. Inasmuch as the materialist speaks ironically of formless matter and matterless forms, in the same breath with perishable forms of imperishable matter, it is plain that materialism is not informed any more than idealism as to the relation of content to form, of a phenomenon to the essential nature of its subject. Where do we find such eternal, imperishable, formless matter? In the world of sense perceptions we never meet anything but forms of perishable matter. It is true that there is matter everywhere. Wherever anything passes away, something new instantly arises. But nowhere has any homogeneous, unchangeable matter enduring without any form, ever been discovered. Even a chemically indivisible element is only a relative unit in its actual existence, and in extension of time as well as in extension through space it varies simultaneously and consecutively as much as any organic individual which also changes only its concrete forms, but remains the same in its general nature from beginning to end. My body changes continually its fleshy tissue, bones,