In-der-Blog-sein

Neurotic Crocodile is also writing a paper with Heraclitus fragment 64 ("The thunderbolt steers all things.").

As lightning appears in the sky, it quickly illuminates all of the different objects in its sphere. I thought maybe concealment could simply mean to make apparent or visible. I also thought some of Heraclitus' unity-through-simplicity was at work here as well: lightning makes every tree, brush, frog, etc. apparent in a distinct way as it lights up the sky but at the same time is a unified in the fact that they are all illuminated by lightning at once.

However, reading this passage, I notice that Heidegger attaches a much deeper meaning to concealment, and what it means to be unconcealed. If concealment is not simply being hidden but appearing as something that it is not, nonconcealment or coming out of concealment would be seeing a thing as it truly is. So, lightning would steer the universe by illuminating but not our everyday illumination. If lightning lets us see a tree, it's not just that we see the tree but that we see it as it really is.

Emphasis in the original.

I think this matter is more subtle and complicated. For example, here's Heideggerian Denken on concealment.

Every unconcealing of a being as something in particular conceals other ways that that being can be unconcealed. By doing so it conceals “beings as a whole,” or the open comportment that lets beings appear, forgetting the manner of its showing as presencing through unconcealment in preference to what is shown. By doing so man forgets the basis of every appearing and takes as self-evident a given mode of comportment and a particular way of appearing. As every unconcealing is a concealing, every aletheia is a lethe, untruth must be part of our analysis and cannot simply be ignored We must, then, understand untruth positively as concealment/concealing.

See his blog for the references. Clearly Heidegger is on about more that than just seeing phenomena or not. And he gets more nuanced the more he thinks about it.  ¶ 5:25 AM