Referring to his distinction between truth as unconcealment and truth as correctness, Heidegger in the 1931–32 course Vom Wesen der Wahrheit, a course devoted to the interpretation of Plato’s Cave Analogy and a part of the Theaetetus, asserts that Plato’s philosophy “is indeed nothing but a battle between these two conceptions of truth” (“ist ja nichts anderes als Kampf der beiden Wahrheitsbegriffe,” GA 34, 46), an assertion that is repeated in the 1933–34 version of the same course (GA 36/37, 124, 127). In the later 1937–38 course Grundfragen der Philosophie, a course in which Heidegger originally intended to provide an interpretation of the Cave Analogy but never got around to doing so (see GA 45, 223), Heidegger presumably has the same idea in mind when he asserts : “Each of his [Plato’s] dialogues, indeed practically every segment of his dialogues, points either directly or indirectly in the direction of the question of ἀλήθεια” (222). This interpretation of Plato’s philosophy as nothing but a battle between truth as unconcealment and truth as correctness is what explains Heidegger’s promotion of the Cave Analogy in the Republic, in which he sees this battle waged most clearly and explicitly, to the central text of Plato’s philosophy, indeed, to a completely self-contained résumé of Plato’s thought. Thus, when he claims that the war between the two conceptions of truth can be found in every dialogue (GA 36/37, 128), he also claims that the Cave Analogy can be found in every dialogue (124). The Cave Analogy can be ripped out of the Republic, Heidegger insists, without this in the least affecting its content or meaning (GA 34, 18). One can thus conclude that there is in Heidegger’s reading of Plato in the 1930s a reduction of the Cave Analogy to the battle between two conceptions of truth, and a reduction of all of Plato’s dialogues to the Cave Analogy.
In the 1926 course Grundbegriffe der antiken Philosophie (GA 22), and even in the 1929 Einführung in das akademische Studium (GA 28, 347–61), both texts in which Heidegger interprets the Cave Analogy, there is no hint of the interpretation of this analogy, much less of Plato’s work as a whole, as a battleground between two conceptions of truth. Starting in the 1930s, however, this becomes Heidegger’s dominant interpretation of Plato, and this interpretation receives its best-known exposition in the 1940 essay “Platons Lehre von der Wahrheit” (PLW). It is not until the 1960s, with the essay “Das Ende der Philosophie und die Aufgabe des Denkens” (ZSD, 61–80), that Heidegger’s interpretation is substantially modified, though not through any rereading of Plato’s texts. There he grants that the Greeks always experienced truth (ἀλήθεια) as correctness (ὀρθότης) and therefore concludes that his earlier thesis of a transformation in the essence of truth from unconcealment to correctness is untenable (“unhaltbar”) (78). In other words, the battle between unconcealment and correctness is already lost to the derivative correctness well before Plato comes onto the scene. But if this is in some sense a retraction of Heidegger’s earlier interpretation of Plato, it is also in another sense its natural outcome. As will be shown below, between the 1931–32 course and the 1940 essay the battle between the two conceptions of truth becomes on Heidegger’s reading increasingly uneven: while in the 1931–32 interpretation the dominant conception of truth in Plato is unconcealment, with truth as correctness only beginning to emerge in its dependence on this prior conception of truth, by the 1940 essay it is truth as correctness that Heidegger sees as dominant in Plato, with only faint traces of the more original conception remaining. The conclusion in the 1960s that truth is experienced only as correctness in Plato, and even before Plato, is only the next and final step in the direction of Heidegger’s critique of Plato as it has developed since the beginning of the 1930s. This is why Heidegger’s retraction in the 1960s does not bring with it any rereading of Plato’s philosophy.
The task of the next chapter is to assess and chart the development of Heidegger’s critique of Plato, namely, the critique that in Plato there is a reduction of truth to mere correctness that blocks any genuine questioning of both the meaning of truth and the meaning of being. Heidegger’s certainly questionable reduction of Plato’s philosophy to the question of the essence of truth will not be directly challenged here, but it will be seen not to be quite as reductive as it might at first seem. The question of truth is not for Heidegger a mere question of epistemology, and his interpretation of Plato on truth will be seen to be an interpretation of Plato’s “ideas” as such and the idea of the good in particular. Indeed, despite Heidegger’s insistence on the independence of the Cave Analogy from its context, his interpretation of Plato will be seen to depend primarily on the account of the good in the Sun Analogy. Therefore, Heidegger’s reading can be said to engage the whole of Plato’s philosophy on the ontological level, though he can still be criticized for excluding as purely derivative and irrelevant to Plato’s real philosophy the politics and ethics that in fact comprise the bulk of the Republic.1 The next chapter will follow Heidegger in his exclusive concern for Plato’s ontology to show that even here and on his own terms his reading of Plato cannot stand .
Yet the account of Heidegger’s interpretation of truth in Plato cannot end with the examination of his evolving interpretation of the Cave and Sun analogies, even though most accounts do end here or, rather, do not go much or at all beyond the published 1940 essay. Yet what is thereby neglected is the other interpretation offered in the 1931–32 course: an interpretation of Plato’s Theaetetus.2 This is at least partly because the 1940 essay drops all reference to the Theaetetus from its argument. Yet in the 1931–32 course the Theaetetus plays an absolutely central role in Heidegger’s argument regarding a transformation in the essence of truth. There the Cave Analogy is not taken by itself to show that Plato understood truth as correctness. On the contrary, Heidegger there asserts the aim of his interpretation of the Cave Analogy to be that of gaining a better understanding of ἀλήθεια as unconcealment and of its intimate connection with the essence of man, as indeed a happening of this essence (117). Where criticism begins is in the context of what Heidegger later claims to be the decisive outcome of the interpretation of the Cave Analogy: that reflection on the essence of truth as unconcealment is impossible without reflection on the essence of untruth as concealment, that the question of the essence of truth must transform itself into the question of the essence of untruth (127). As Heidegger asserts, “the question of untruth is no detour [Umweg], but the only way possible, the direct way to the essence of truth” (128). In this context, Heidegger suggests that, however central an understanding of truth as unconcealment may be to the Cave Analogy, Plato failed to think the essence of concealment and therefore inaugurated a turn away from unconcealment in the conception of truth. But to show this, Heidegger must consider how Plato thought about and understood untruth. This is where the turn to a reading of the Theaetetus becomes absolutely indispensable, because it is in this dialogue, according to Heidegger, that Plato genuinely walked a part of the way of the question of untruth “for the first and last time in the history of philosophy” (129). Only if Heidegger can show that along this way Plato fails to grasp untruth as concealment, and instead identifies it with mere error in thinking and speaking, can he show that Plato understood truth as mere correctness in speaking and thinking (see 143).
But if this is the case, then why does Heidegger later abandon all reference to the Theaetetus in his account of Plato’s “doctrine of truth”? Such an abandonment is already underway in the 1933–34 version of the Vom Wesen der Wahrheit course, since already there we see the interpretation of the Theaetetus drastically cut in comparison to the 1931–32 version. Why then this marginalization and eventual complete disappearance of the Theaetetus from the account of Plato’s “doctrine of truth”? There are a number of possible answers here, ranging from the purely practical to the philosophical.3 Chapter 4, however, seeks to show what must have been at least a very important factor: Heidegger’s extraordinarily perceptive and careful reading of the Theaetetus simply does not support his thesis, so that the thesis must later be made to rest entirely on the Cave Analogy, a shift of the burden of proof already begun in the 1933–34 version of the course. This thesis is forgotten through much of Heidegger’s reading of the Theaetetus and when it suddenly appears at the very end of the course, without the support of the texts Heidegger discusses, much less those he does not discuss, it cannot help but look like a deus ex machina. What Heidegger uncovers in the Theaetetus is a conception of our relation to being and truth that cannot be reduced to any kind of correspondence and therefore resists an interpretation of untruth as incorrectness. But then the argument of chapter 4 is not the purely negative one that Heidegger misinterpreted Plato. The aim instead is to show that Heidegger’s engagement with the text of the Theaetetus, an engagement that begins already in the 1926 course Die Grundbegriffe der antiken Philosophie but is eventually abandoned in favor of the historical construct of Platonism, offers a special opportunity for glimpsing what might have become a genuine dialogue and affinity between Plato and Heidegger. In Heidegger’s account of the history of metaphysics as Platonism, the Theaetetus interpretation is the discarded trace of a very different reading of Plato.
There is another “marginal” text in Heidegger’s reading of Plato, and significantly it too concerns the essence of untruth. In 1942, the year in which “Plato’s Doctrine of Truth” was first published, Heidegger, in a course ostensibly devoted to Parmenides, offers a brief and partial reading of the Myth of Er in Book 10 of the Republic.4 What primarily comes to expression in this myth, on Heidegger’s reading, is λήθη, concealment. What Heidegger finds in Plato’s myth, a myth whose significance was presumably hidden from him in 1931–32 when he asserted the Theaetetus to be the first and last time in the history of philosophy that the way of questioning concealment was genuinely taken, goes well beyond what Plato was credited with in 1931–32. While in the 1931–32 course Heidegger interprets the Greek word for untruth, ψεῦδoς, as meaning Verdrehung and argues that truth is thereby necessarily interpreted as Nichtverdehen and Treffen (138), in the 1942 course Heidegger interprets ψεῦδoς as a concealing that is also a letting appear and accordingly sees this name for untruth as supporting and confirming the understanding of ἀλήθεια as unconcealment (43–48). Furthermore, while in 1931–32 Heidegger asserts that the Greeks interpreted λήθη as a mere not-being-present-at-hand (142), in the Myth of Er he finds a genuine experience and thinking (An-denken) of λήθη (190). A reason for these shifts is that in 1942 it is the Roman interpretation of truth and untruth that is seen as the decisive step towards the identification of the two with correctness and falsehood. Nevertheless, even in the 1942 course we find repeated the claim that Plato interpreted truth as correspondence, but here, as in the case of the interpretation of the Theaetetus, this claim is a mere assertion in tension with what is revealed by Heidegger’s reading of the text.
The form of these two texts marginal to Heidegger’s main interpretation of Platonism is certainly significant: one is a dialogue and the other is a myth. One can of course claim that all of Plato’s works are dialogues, but Heidegger certainly does not read them all in this way. While Heidegger abstracts the Cave Analogy from its dialogical context in the Republic and reads the Sophist in the 1924–25 course as a treatise, he emphasizes the dialogical character of the Theaetetus (see 194, e.g.).5 As for the Myth of Er, he gives great importance to its character as mythic discourse, insisting that this discourse is a form of nonmetaphysical saying (145). What Heidegger’s reading of both the Theaetetus and the Myth of Er may therefore show is the extent to which a reading of Plato that is attentive to both the dialogical and the mythic discourse in his works resists the metaphysical doctrine (Lehre) with which he wishes to identify Plato. In his account of the history of metaphysics as Platonism, Heidegger strangely marginalizes his own readings of the texts that resist such an account. The argument of chapters 4 and 5 is that what gets marginalized here is precisely what should be made central. If Heidegger anywhere genuinely engages Plato’s thought, it is not in “Plato’s Doctrine of Truth,” but in his reading of the texts that problematize and therefore get excluded from this doctrine.