III. Thinking as the Instrument of Knowledge

Whatever principle we choose to lay down, we must either prove that somewhere we have observed it, or we must enunciate it in the form of a clear thought which can be re-thought by any other thinker. Every philosopher who sets out to discuss his fundamental principles must express them in conceptual form and thus use thinking. He therefore indirectly admits that his activity presupposes thinking. We leave open here the question whether thinking or something else is the chief factor in the development of the world. But it is at any rate clear that the philosopher can gain no knowledge of this development without thinking. In the occurrence of phenomena thought may play a secondary part, but it is quite certain that it plays a chief part in the forming of a view about them.