Modern science is natural science. Science is deemed worthy of its name only in so far as it is natural science. In other words, only that thought is scientific which consciously has real, perceptible, natural things for its object. For this reason representatives and friends of science can not be enemies of nature or of matter. Indeed they are not. But the very existence of science shows that this nature, this world of sense perceptions, this matter or substance, does alone and by itself not satisfy us. Science, or thought, which has material practice or being for its object, does not strive to reproduce nature in its integrity, in its entire perceptible substance, for these are already present. If science were to aim at nothing new, it would be superfluous. It is entitled to special recognition only to the extent that it carries a new element into matter. Science is not so much concerned in the material of its study as in understanding. Of course it is the understanding of this material which is desired, the understanding of its general character, of the fixed pole in the succession of phenomena. That which religion supernaturally separates from the material, which science opposes to the material as something higher, diviner, more spiritual, is in reality nothing but the faculty of rising above multiformity, of proceeding from the concrete to the general. The nobler spiritual interests are not absolutely different from the material interests, they are not qualitatively different. The positive side of modern idealism does not consist in belittling eating and drinking, the pleasure in earthly possessions and in intercourse with the other sex, but rather in pleading for the recognition of other material enjoyments besides these, as for instance those of the eye, the ear, of art and science, in short of the whole man. You shall not indulge in the material revelries of passion, that is to say you shall not direct your thought one-sidedly to any concrete lust, but rather consider your entire development, take into account the total general extension of your existence. The bare materialist principle is inadequate in that it does not appreciate the difference between the concrete and the general, because it makes the individual synonymous with the general. It refuses to recognize the quantitative superiority of the mind over the world of sense perceptions. Idealism, on the other hand, forgets the qualitative unity in the quantitative difference. It is transcendental and makes an absolute difference out of the relative one. The contradiction between these two camps is due to the misunderstood relation of our reason to its given object or material. The idealist regards reason alone as the source of all understanding, while the materialist looks upon the world of sense perceptions in the same way. Nothing is required for a solution of this contradiction but the comprehension of the relative interdependence of these two sources of understanding.