They are then transferred to the fictitious world of atoms. And then we are astonished that we fail to evolve concrete life out of this principle of our own making, which we have borrowed from the world of percepts. That the Dualist, working as he does with a completely empty concept of the thing-in-itself, can reach no explanation of the world, follows from the very definition of his principle which has been given above. In any case, the Dualist finds it necessary to set impassable barriers to our faculty of knowledge. A follower of the Monistic theory of the world knows that all he needs to explain any given phenomenon in the world is to be found within this world itself. What prevents him from finding it can be only chance limitations in space and time, or defects of his organisation, i.e., not of human organisation in general, but only of his own. It follows from the concept of knowledge, as defined by us, that there can be no talk of any limits of knowledge. Knowledge is not a concern of the universe in general, but one which men must settle for themselves. External things demand no explanation. They exist and act on one another according to laws which thought can discover. They exist in indivisible unity with these laws. But we, in our self-hood, confront them, grasping at first only what we have called percepts. However, within ourselves we find the power to discover also the other part of reality. Only when the Self has combined for itself the two elements of reality which are indivisibly bound up with one another in the world, is our thirst for knowledge stilled. The Self is then again in contact with reality. The presuppositions for the development of knowledge thus exist through and for the Self. It is the Self which sets itself the problems of knowledge. It takes them from thought, an element which in itself is absolutely clear and transparent. If we set ourselves questions which we cannot answer, it must be because the content of the questions is not in all respects clear and distinct. It is not the world which sets questions to us, but we who set them to ourselves. I can imagine that it would be quite impossible for me to answer a question which I happened to find written down somewhere, without knowing the universe of discourse from which the content of the question is taken.