The principle of reason reads: Nothing is without reason. Nihil est sine ratione. "Reason" [Grund] is the translation of ratio. A translation becomes a legacy when the speaking of basic words translates one historical language into another one. If it rigidifies, a legacy can degenerate into a burden and a handicap. It can become this because a legacy [Überlieferung] is genuinely, as its name says, a delivering [Liefern] in the sense of liberare, of liberating. As a liberating, a legacy raises concealed riches of what has-been into the light of day, even if this light is at first only that of a hesitant dawn. That Grund is the translation of ratio means to say that ratio has passed over into Grund, a legacy which already early on speaks with a double sense. Of course, the passing over of the two senses of ratio into "grounds" and "Reason" first reaches its decisive configuration where the Geschick of being determines that epoch which, according to historiographical periodization, is called "modernity." Provided being and ground/reason "are" the same, then the modern Geschick of being must also transform the ancient Roman double sense of ratio.
As separate as the two senses in the double sense of ratio may be—namely "ground" as footing and earth and "Reason" as perception and hearing—both meanings are allied already early on, even if one did not expressly think about their belonging-together. We must say in a more appropriate manner that both tendencies of this double sense—Reason and grounds—are traced out in what ratio names. Then what does ratio mean? We answered with the translation of the word ratio; "reckoning. " But here "reckoning" is to be thought in the sense of the verb reor, which is related to the noun ratio. "Reckoning" means "to orient something in terms of something," "to represent something as something." That as which some particular thing is represented [vorgestellt] as being, is what it is imputed [das Unterstellte] as being. Broadly conceived, this reckoning also determines the sense of the word "calculus." One speaks of mathematical calculus. But there is also another kind. Even Hölderlin used the word "calculus"