Nancy J. Holland on Heidegger's lectures on Plato's cave allegory and Theaetatus (GA 34).

These lectures offer much of the same account of our existence as conscious (or "ensouled") beings that we have found throughout Heidegger's work. However, they undermine traditional philosophy/metaphysics in a much more radical way. The section on the Republic includes a cryptic parenthetical note from the presentation of the lectures that reads, "(commonly: 'object'—'subject'; actually: manifestness, understanding of being)" (Heidegger 2002a, 81). That is, as Dasein, we can have explicit truth, or untruth, only because the "soul" is understood as intrinsically relational (as Heidegger argues the Greeks understood it). We encounter entities in the world primarily as unconcealed from the background of tacit awareness, as manifest to us. To exist as Dasein is to exist in relation to Being, whether we are aware of it or not. Earlier in these lectures, he attributes to the "Theaetetus" the view that "the soul is itself a being-extended-to, a passage-way, an extending over to. It is the soul which, in its own relating of itself to something giveable, makes possible comportment towards" (Heidegger 2002a, 142; compare "being held out into the nothing" in "What is Metaphysics?" [Heidegger 1993, 103]).

This is how Heidegger reaches the position quoted in chapter 1: "These connections of being are not as such conceived and made into objects, but are there only in so far as they are reckoned with—how so? By perceiving and experiencing and dealing (and so forth) with beings" (Heidegger 2002a, 161). The technological "age of the world picture," by contrast, gives us a wrong, not to say perverse, understanding of truth as a representation that accurately reproduces an independent external reality. When God no longer serves as a universally acknowledged guarantor of the correctness of our beliefs in this Cartesian picture, as we have seen, modernity falls prey to more or less mitigated skepticism. Furthermore, we can see the manipulation of now decontextualized truths for the political and economic advantages of those with the power to fill the media with claims about global warming, evolution, and other matters that violate the dictates of science itself.

In effect, in these lectures and the earlier paper, "On the Essence of Truth," Heidegger has replaced temporality (which remains a metaphysical concept) with truth/alétheia as the key to understanding the being of Dasein. He has attempted to move beyond metaphysics not simply by reversing, the and negative poles of the. traditional metaphysical opposition, but also by embedding one in the other—the essence of truth is untruth—and then complicating the now "dominant" pole through the analysis of pseudos and its relationship to what is hidden/revealed in alétheia. And finally, he has shifted the discourse from the truth of beings to the Being of truth. Correlatively, Dasein is now not a being based in temporality, but is instead an openness oriented primarily toward comportment and secondarily toward beings as the beings they are (or are not). What is ordinarily understood by "truth" is, in turn, derived from that secondary kind of truth and ignores the truth of Being itself.

Pp. 79-80