Idealism sees only the difference, materialism sees only the uniformity of matter and mind, content and form, force and substance, sense perception and moral interpretation. But all these distinctions belong to the one common genus which constitutes the distinction between the special and the general. Consistent materialists act like purely practical men without any science. But, since knowing and thinking are real attributes of man regardless of his party affiliation, purely practical men do not exist in reality. Even the merest attempt at practical experiment on the basis of experienced facts differs only in degree from scientific practice based on theoretical principles. On the other hand, consistent idealists are just as impossible as purely practical men. They would like to have the general without the special, the spirit without matter, force without substance, science without experience or material, the absolute without the relative. How can thinkers who search for truth, being, relative causes, such as naturalists, be idealists? They are so only outside of their specialties, never inside of them. The modern mind, the mind of natural science, is immaterial only so far as it embraces all matters. But men like the astronomer Madler find so little of the ridiculous in the current expectation of the materially increased spiritual power after our "emancipation from the bonds of matter," that he has nothing better to substitute for it and flatters himself with having defined the "bonds of matter" as material attraction. Truly, so long as mind is still conceived in the form of a religious ghost, the expectation of an increased mental power after the emancipation from the bonds of matter is not so much an object for ridicule as for compassion. But if we regard mind as the expression of modern science, we offer the better scientific explanation for the traditional faith. By bonds of matter we do not mean, in that case, the bond of gravitation, but the multiplicity of sense perceptions. And matter holds the mind in bondage only so long as the faculty of thought has not overcome the multiplicity of things. The emancipation of the mind from the bonds of matter consists in developing the general element out of the concrete multiplicity. +(c) Force and Matter.+ The reader who has closely followed our main idea, which will be further illustrated, will anticipate that the question of matter and force finds its solution in the understanding of the relation between the general and the special. What is the relation of the concrete to the abstract? This is the common problem of those who see the active impulse of the world either in the spiritual force or in the material substance, who think to find the nature of things, the _non plus ultra_ of science, in either of these facts.