A satisfactory Logic then presupposes or implies a complete system of philosophy. No doubt, for a logic which deals with the minor problems of ratiocination or formal induction, all that is needed is a certain general acquaintance with popular conceptions, and with the results or methods of physical science. But if logic takes its business seriously, it must go behind these presuppositions. It must trace back reasoning to its roots, fibres, and first principles. And to do that it is not enough to put at the front a psychological chapter. Far from helping, psychology in these matters is much more in need of being helped itself. Till it has learned a little of the puzzle of the one and the many, the same and the diverse, being, quality, and essence, psychology will be as little use to Logic as blind guides generally are. Nor need this prevent us from saying that when psychology has thoroughly learned these mysteries, it will give fresh life and reality to the logic which it touches upon. The principles of Logic lie in another field,[6] and are deeper in the ground, than obvious psychological gossip. If Logic then deals with form, it deals with a form of forms--the form of the world, of life, and of reality. It is a form, which is a unity in diversity, an organism,--a form which is infinitely manifold, and yet in all its multiplicity one. Logic is the morphology of thought,--of that thought which in Nature is concealed under the variety and divisions of things, and which in the theory of mental and spiritual life is resumed into a complete biology of the world-organism. The problem of Logic then demands an abstraction--an effort of self-concentration--an effort by which the whole machinery of the sensible universe shall be left behind, and the accustomed clothing of our thoughts be removed. To move in this ether of pure thought is clearly one of the hardest of problems.