Lecture Nine [126-128]
conditions for the possibility" is the rendering of sufficient reasons, of ratio sufficiens, which as ratio is pure Reason. According to Kant it is only by having recourse to Reason (ratio) that something can be determined as to what it is and how it is a being for the Rational creature called "man . " However, this now means not just that beings are only qua Objects and Objects only Objects for a subject in the sense of modern thinking; rather, it now becomes clearer that this subject, that is, Reason, ratio, that is, the assembling of the a priori conditions for the possibility for nature and freedom, is this assembling only in rendering sufficient reasons.
We now see what a fragment of early Greek thinking says within quite a different light:
τὸ γὰρ αὐτὸ νοεῖν ἐστίν τε καὶ εἶναι36
That, namely the same, is perceiving as well as being.
When conceived in a modem way, this means that perceiving, Reason (ratio), and being belong together, and indeed such that pure Reason, ratio, is nothing but the positing, the rendering, of sufficient reasons for whatever there is in view of how it appears as a being, which means, how it can be represented and ordered, dealt with and handled.
Nothing prevents us from being content with discussing the term "critique of pure Reason" as a historically handy label for Kant's first main work. However, we can also ponder the extent to which Kant's thinking stands thoroughly under this term as under a demand. Pure Reason, theoretical and practical Reason, will then show itself as ratio pura in the sense that it posits the ground/reason, that is, the ground/reason for all founding; it is what is determinative for all conditions for the possibility of beings in their unity. The Critique of Pure Reason brings the ground/reason for every foundation into its definitive form. Insofar as thinking becomes a critique of pure Reason through Kant, it responds to the demand of the principium rationis suffidentis. Through this response Kant's thinking brings the claim of the principium rationis to the fore in its full breadth , and indeed so much so that ratio is ground/reason only in the sense of ratio as Reason, as the faculty for fundamental principles.
This reference to what conceals itself behind the tide Critique of Pure Reason nevenheless remains quite inadequate as long as the whole of Kant's three Critiques does not become present in a vividly reconstructive perusal. Seen externally, these three works lie next to each other unconnected, like three boulders. Kant himself tried over and over again to make the inner unity, which he certainly saw, visible through a rather external architectonic. Yet Kant knew more than he was capable of presenting through this architectonic of his works.
Nevertheless, what above all thwarts our insight into the essence of what