To think about the world is to transmute the given world by means of concepts and ideas. Thinking, thus, is in very truth the act which brings about knowledge. Knowledge can arise only if thinking, out of itself, introduces order into the content of the world as given. Thinking is itself an activity which produces a content of its own in the moment of cognition. Hence, the content cognised, in so far as it has its origin solely in thinking, offers no difficulty to cognition. We need only observe it, for in its essential nature it is immediately given to us. The description of thinking is also the science of thinking. In fact, Logic was never anything but a description of the forms of thinking, never a demonstrative science. For, demonstration occurs only when there is a synthesis of the products of thinking with a content otherwise given. Hence, Gideon Spicker is quite right when he says in his book, Lessing's Weltanschauung (p. 5): "We have no means of knowing, either empirically or logically, whether the results of thinking, as such, are true." We may add that, since demonstration already presupposes thinking, thinking itself cannot be demonstrated. We can demonstrate a particular fact, but we cannot demonstrate the process of demonstrating itself. We can only describe what a demonstration is. All logical theory is wholly empirical. Logic is a science which consists only of observation. But if we want to get to know anything over and above our thinking, we can do so only with the help of thinking. That is to say, our thinking must apply itself to something given and transform its chaotic into a systematic connection with the world-picture. Thinking, then, in its application to the world as given, is a formative principle. The process is as follows. First, thinking selects certain details out of the totality of the Given. For, in the Given, there are strictly no individual details, but only an undifferentiated continuum. Next, thinking relates the selected details to each other according to the forms which it has itself produced. And, lastly, it determines what follows from this relation. The act of relating two distinct items of the world-content to each other does not imply that thinking arbitrarily determines something about them. Thinking waits and sees what is the spontaneous consequence of the relation established. With this consequence we have at last some degree of knowledge of the two selected items of the world-content. Suppose the world-content reveals nothing of its nature in response to the establishment of such a relation, then the effort of thinking must miscarry, and a fresh effort must take its place. All cognitions consist in this, that two or more items of the Given are brought into relation with each other by us and that we apprehend what follows from this relation.