When heard in the other tonality as a principle of being, the principle of reason says this: being and ground/reason: the same; being: the a-byss. We seem to plunge into the fathomless via this principle. But something else happens. The principle of being shocks us, and from a direction we do not expect. In order to absorb the approaching shock, it will be necessary to bring into view all that came into view in the previous lecture, and do so with a view to its gathering unity. As a Principle, as the supreme fundamental principle, the principle of reason is a general principle. Whatever is ungraspable in general principles is normally due to the fact that we neglect to apply them. An application turns to individual cases which then, as examples taken from what is clear as day, convey to us what the principle says generally and, as it were, without any real support. Now, we apply the principle of reason more often than we think. Everywhere we find things founded and such thi that found, even if it is only in the prevalent mode of causation. What effects and is effected, what grounds and is grounded is, in our eyes, the whole of what is real. The principle of reason articulates what, for it, is obvious in the form Nihil est sine causa. Seen in this way, the principle of reason holds nothing ungraspable. This strikes us only when we contemplate the principle of reason in the opposite direction, so to speak—not in the direction of the regions and fields of its application, but rather in the direction of its own provenance, in the direction of that from whence the principle itself speaks. What is ungraspable about the principle now no longer lies in a neglect on our part to apply [Anwendung] it, but in the principle lodging [Zu-wendung] its claim on us. This, from whence the claim of the principle speaks, we call the site of the principle of reason. The path that is to lead to this site and is to first explore this site, we call the discussion situating the principle of reason.
Everything rests on the path. This means two different things. First, it means that it all comes down to the path, to our finding it and remaining on it—