It might be useful if, with the first steps we must take on the path of this lecture, we pay attention to which clue we are following and into what province this leads us. The path moves towards the principle of reason, towards what the principle says, whereof it says what it says and how it says it. The principle of reason reads: Nihil est sine ratione; nothing is without reason. We did not go into the content of the principle. The path immediately turned away from this obvious tack. Rather, we reflected on what sort of principles to which the principle of reason might belong. Philosophy includes it among the supreme fundamental principles that are also called Principles. Since we are thinking about the principle of reason as a fundamental principle, the next clue leads us, so to speak, along the periphery of the principle. We avoid straightaway touching its interior, the content of the principle. What is disconcerting about this principle is that the path around its outside has already given us more than enough to think about. Later we will have to see whether this procedure has served us well, which means, to what extent this procedure has brought us closer-and perhaps even in a better way-to the content of the principle than if we were now to attempt straightaway a discussion of its contents.
Therefore we do not want to let the thread grasped in the first session fall by the wayside prematurely. It should lead us to a position from which we obtain a more intimate knowledge of how the principle of reason shows up in the field of Western thinking. We thus make a first acquaintance with the principle of reason as a fundamental pr inciple. From this comes an insight into our customary relationship to the principle of reason. But this insight into our relationship to the principle of reason sheds a light both on ourselves and on our customary way of thinking. So it may be that the principle of reason, when considered in this way, will also disclose something to us about our own essence, and this without our being preoccupied with ourselves.
We may or may not know it , we may or may not pay panicular attention