The principle of reason is a statement about beings. To that extent, it is also a statement about being itself, if it is the case that “the shining of being is in play in the appearing of beings” (GA 10, 81/PR, 54). If the principle of reason is at first heard as a statement about beings, it then resonates as a statement about being. For to state that every being has a reason implies a prior implicit reference to being: one cannot make any determination with respect to a being without having first decided about the being of that being. “The fundamental principle of reason says: every being has a reason. The principle is a statement about beings. But we experience a being as a being only when we attend to the fact that and how it is. Hence, in order to really hear the principle about beings we must become aware that the ‘is’ in the principle ‘nothing is without reason’ sets the pitch that tunes everything” (GA 10, 183/PR, 125). The principle of reason, even when heard ontically, is already harboring an ontological scope. The determining factor in the principle of reason is not ontical, but ontological. This is what allows Heidegger to evoke the other tonality of the principle of reason, the other way of hearing what the principle states, one that indicates the passage (the “leap”: Satz) from the ontical to the ontological scope of the principle of reason: “When we listen to it, that is, when we open ourselves to what really speaks in the principle, the principle suddenly intones differently. No longer ‘nothing is without reason,’ rather, ‘nothing is without reason’” (GA 10, 183/PR, 125). When heard in that way, that is, by highlighting the “is,” one passes (leaps) from the ontical to the ontological, from beings to being: “Whenever it speaks of beings, the tiny word ‘is’ names the being of beings” (GA 10, 183/PR, 125).
The saying of the principle of reason, Nihil est sine ratione, can thus be heard in two ways: “We can say: ‘Nihil est sine ratione.’ ‘Nothing is without reason.’ In the affirmative form this means: everything has a reason. Yet we can also set the pitch in this way: ‘Nihil est sine ratione.’ ‘Nothing is without reason’” (GA 10, 60/PR, 39–40). Heidegger emphasizes the “is” in the statement, associating the “is” with reason, revealing that Grund, reason/ground, belongs to being as such. “‘Nothing is without reason.’ When one paraphrases this customary formulation of the principle of reason, it reads: ‘Every being has a reason.’ With this, the reason that every being has is itself represented as some being. A reference earlier to a text of Leibniz was supposed to show this. The principle of reason is a statement about beings. In the other tonality, the principle of reason sounds like this: ‘Nothing is without reason.’ When paraphrased, this means ‘ground/reason belongs to being.’ Or ‘being and ground/reason-the same.’ Heard in this way the principle speaks of being” (GA 10, 111/PR, 75). If one hears the statement of the principle of reason as emphasized in this way: “Nothing is without reason,” one detects an affinity between being and reason itself: “The intonation allows us to hear a unison between the ‘is’ and ‘reason,’ est and ratio” (GA 10, 69/PR, 46). Now, Heidegger asks, “What do we bring into view when we think about the principle of reason in the tonality introduced here?” The statement, “Nothing is . . . without reason,” says: “‘Nothing,’ that is, no being whatsoever ‘is—without reason’” (GA 10, 72–73/PR, 49). No being is without reason: the “is” names being itself: “Even if it does so completely indeterminantly, the ‘is’ always names the being of some being” (GA 10, 73/PR, 49). This means that the statement of the principle of reason addresses beings in their being and is to be heard as an ontological statement. “So the principle of reason, which is offered as a statement about beings, says: to the being of beings there belongs something like ground/reason” (GA 10, 73/PR, 49). The principle of reason must be approached in its ontological (and not simply ontical) scope: “Consequently, the principle of reason proves to be not only a statement about beings; even more, what we bring into view is that the principle of reason speaks of the being of beings” (GA 10, 73/PR, 49). The new emphasis allows one to bring being into view and to reveal the proximity of reason with being: “But finally we heard the principle of reason in a different tonality. Instead of ‘Nothing is without reason,’ it now sounds like this: ‘Nothing is without reason.’ The pitch has shifted from the ‘nothing’ to the ‘is’ and from the ‘without’ to the ‘reason.’ The word ‘is’ in one fashion or another invariably names being. This shift in pitch lets us hear an accord between being and reason” (GA 10, 75–76/PR, 50).
This should be understood in its ontologico-historical significance, Heidegger evoking the “Geschick of being,” the destiny, sending, or dispensation of being, which always happens as a withdrawal: “being proffers itself to us while at the same time withdrawing its essence, concealing this essence in the withdrawal” (GA 10, 91/PR, 62). In such a withdrawal, which leaves reasons, causes, and grounds, being appears as ground. In the thirteenth lecture, Heidegger first recalls what he means by “Geschick of being,” namely that being gives itself as a withdrawal: “When we were led to say more clearly what the talk of the history of being as the Geschick of being is supposed to mean, we referred to the fact that being, in that it proffers, clears and lights itself, at the same time withdraws” (GA 10, 164/PR, 110). He then associates such withdrawal with the identification of being with reason/ground: “Now we can more clearly hear the words about the withdrawal of being. The words say that being conceals itself as being; namely, in its inaugural Geschick as logos being conceals its belonging-together with ground/reason.” The withdrawal of being brings reason and ground to the fore: “But the withdrawing does not exhaust itself in this concealment. Rather, inasmuch as it conceals its essence, being allows something else to come to the fore, namely ground/reason in the shape of archai, aitiai, of rationes, of causae, of Principles, Ursachen [causes] and Rational grounds. In withdrawing being leaves behind these shapes of ground/reason whose provenance goes unrecognized” (GA 10, 164/PR, 110). In its withdrawal, being gives itself as rational ground.
By hearing the principle of reason in its ontological sense, Heidegger is able to stress the affinity between being and reason. Indeed, if beings are said to be founded in reason, and being is that which determines beings as such, then it appears that reason is one possible name in a certain historical configuration for being itself. Now, to state that there is an affinity between being and reason, or that reason “belongs” to being, or even that “being and reason: the same,” cannot mean that being itself has a reason or is grounded in reason. That never is the case. “‘Ground/reason belongs to being’—one might be inclined to understand this in the sense of ‘being has a reason,’ that is, ‘being is grounded.’ The popularly understood and presumably valid principium rationis never speaks of this” (GA 10, 76/PR, 51). Why? Because what is grounded in the principle of reason is never being but instead beings, the ontic itself. “According to the principle