the meaning of Plato’s doctrine of ideas. He tries to show that Plato, with his doctrine of ideas and their being, wanted to teach nothing else than the “validity of truths” (p. 513). Validity is the form of actuality that Plato basically had in mind when he spoke of the being of the idea—but, according to Lotze, he had to speak of “being” because the Greeks had no word for validity and the kind of reality it refers to. In his interpretation Lotze is entirely caught in the spell of his narrowed-down concept of being (being = the actuality of sensible things); and he finds that “to ascribe [to Plato] the absurd opinion that the ideas have being” (ibid.), is irreconcilable with his admiration for Plato’s profundity. In particular, Lotze tries to show that even in Plato’s opinion the ideas have “the actuality of validity” (p. 514). For what we must assert of true propositions—their identity and their eternity/supratemporal nature—are determinations that belong to what Plato called ideas. The “content of a truth” in the proposition is “recognized” (i.e., it is not made) by us (p. 515). The truth already “has been valid” and will be valid, whether it is thought or not.51 In its actuality, the content of a truth is independent of the minds in which it is thought. So too with the idea as a “form equal to itself.” It is recognized as the same in various appearances (p. 514). The idea is what it is, independent of the things in which it can appear and independent of the minds that can give it the actuality [71] of a mental state. “Thus we think everything in terms of truth” (p. 515).52
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Plato uses the expression ὄντως ὄν53 when he wants to make the distinction between an “actually valid truth and an alleged truth” (p. 514). For Lotze, the fact that Plato designated the idea as οὐσία opened the door to a misunderstanding, because οὐσία means ὑπόστασις, the “out-there-ness” of an existing thing or substance. But ideas are not things. So, with the word οὐσία, Plato covered over what he really meant. But Lotze is speaking here on the presupposition that οὐσία
51. [By “has been valid,” Heidegger means “is valid in its essence.” This is what he calls elsewhere the ontological perfect as in Aristotle’s phrase τὸ τί ἦν τίνι εἶναι, “what something always has been” in the sense of “what it essentially is [ἦν] to be something,” “the essence (of something).” Cf. GA 2, p. 114 n. a.]
52. [Here (Moser, p. 146) Heidegger draws to a close his lecture of Thursday, 19 November 1925, to be followed by that of Friday, 20 November (Moser, pp. 147–164), which began with a 575-word summary (Moser, pp. 147–50) that is omitted in GA 21.]
53. ὄντως ὄν means that which is according to the [full] measure of being; that which is in the [full] sense of being; “is” such as only something that is properly in being can be; being in such a way as fully suffices for being and for the possibility of being. In Lotze’s interpretation of Plato, this proper being points to truth.