One of the central axes in Heidegger scholarship involves the extent to which one can make sense of the following deeply weird passages from Paragraph 44 of Being and Time:
“There is” [“gibt es”] truth only insofar as Da-sein is and as long as it is. Beings are discovered only when Da-sein is, and only as long as Da-sein is are they disclosed. Newton’s laws, the law of contradiction, and any truth whatsoever, are true only as long as Da-sein is. Before there was any Da-sein, there was no truth; nor will there be any after Da-sein is no more. For in such a case truth as disclosedness, discovering, and discoveredness cannot be. Before Newton’s laws were discovered, they were not “true.” From this it does not follow that they were false or even that they would become false if ontically no discoveredness were possible any longer.
This can be read this in a variety of ways, from a nearly trivial stipulation about how we are going to use technical notions of truth or falsity on the one hand to an affirmation of full blown Berkeleyan idealism on the other. Heidegger explicitly tries to distance himself from the idealist extreme. He goes on to write:
The fact that before Newton his laws were neither true nor false cannot mean that the beings which they point out in a discovering way did not previously exist. The laws became true through Newton, thorough them beings in themselves became accessible to Da-sein. With the discoveredness of beings, they show themselves precisely as the beings that they previously were. To discover in this way is the kind of being of “truth.”
But then a few pages later, Heidegger seems to take back precisely this very realist concession.
“There is” [Es gibt] being--not beings--only insofar as truth is. And truth is only because and as long as Da-sein is. Being and truth “are” equiprimordially.
But the three passages together trap Heidegger in an absurdity.* Being is only insofar as truth is. But earlier he has asserted that truth is only insofar as Dasein is. So being is only insofar as Dasein is. But in his rejection of idealism, he has said that beings exist without Dasein. But all of this together would entail the prima facie absurd position that beings exist without being. Some of the best essays in Crowell and Malpas' magnificent Transcendental Heidegger explore these issue, particularly those by Christina LaFont and Herman Phillipse, who uses these and other passages to pose “Heidegger’s problem of the external world.” LaFont and Phillipse separately show that it is very, very difficult to make sense of just exactly what the question of the meaning of Being is supposed to amount to if things can exist without being. Interesting, Phillipse and LaFont's concerns are largely homologous to the concerns raised by Quentin Meillassoux in After Finitude about the entire phenomenological tradition.
Interpreters such as Taylor Carmen or Robert Brandom tend to see the question of the meaning of being as a question of transcendental psychology, that is concerning how minds are able to comprehend that and what things are. As such they have a much easier time dismissing such problem passages. But interpreters such as Graham Harman who take the problem of the meaning of being to have much stronger metaphysical resonance, concerning actuality (that things are) and essence (what they are) (and note that in the Nietzsche lectures Heidegger traces the fall from pre-Socratic wisdom to be precisely the separation of these notions), find Heideggerian philosophy of mind to be a caricature of Heidegger’s essential idea.
As someone who is not a specialist in Heidegder, to me the state of secondary literature seems to be this. Carmen develops a profound Heideggerian philosophy of mind, in part by building on Dreyfus and Okrent’s groundbreaking work, but also in part by ignoring much of what Heidegger has to offer metaphysics. Likewise Harman develops a profound metaphysics by ignoring much of what Heidegger has to offer the philosophy of mind.* Weirdly, French post-structuralist Heideggerians do something in between! That is, current debates about "The Speculative Turn" include debates about whether to read the work of post-structuralists along Carmanian or Harmanian lines. Brad Elliot Stone (here) has utilized P.F. Strawson's work to make the most powerful generalized case for Harmania, a case for which assorted Deleuzians, Simondonians, Whiteheadians, Lacanians, etc. have been paving the way the last decade or so.
In Heidegger's Philosophy of Being Herman Phillipse argues that traditional Heidegger scholarship’s willingness to accept Heidegger’s pretense that there is a univocal problem of being places the scholars in question in a similar epistemic state of those theologians who start interpreting the Bible by taking its (supposed) own assertion of consistency at face value. Since I'm more interested in what we can learn from philosophers Heidegger, I don't feel the need to adjudicate this issue (albeit self-awareness of what one is doing requires registering it).
Rather, what I want to do at least by this Summer is see where Kris McDaniel's metaphysical reading of the Vorhandenheit/Zuhandenheit distinction as well as his program for phenomenological metaphysics fits into Harman's earlier interpretation of Heidegger as well as happenings in "the new continental metaphysics" (as personified by Harman and Stone's positive programs) more generally. From my brief read-throughs thusfar, I think that reading McDaniel from the perspective of recent events in continental metaphysics will be pretty productive.
[*I should note that in A Thing of This World Lee Braver has an interesting take on these passages that ends up having him attribute a view to Heidegger interestingly homologous to Robert Kraut's "Robust Deflationism." A chapter in a book I'm writing is dedicated to this homology. It's interesting stuff.
I should also note that Bill Blattner's work is relevant to all of this in all sorts of cool ways that I hope to untangle.]