I am also reminded of a popular, but flawed, construction that goes like this: "There exists something. There is a border between this and everything else. When this border is crossed twice, you are back where you started." Of course, any serious student of Boolean algebras will also know of Heyting algebras, and thus know that the Heyting algebra has a more general construction where "crossing the border twice" doesn't get you back to where you started. What I mean to insinuate is that one must be careful with these sorts of assertions: mathematicians study constructions of axiomatic assertions, and as a result sometimes have a broader view than the naive philosopher. Some may point at some Zen koan of similar value: that thing which is and isn't. The Zen statements may be mind-opening, but seem to lack the concreteness, the manipulability, the usefulness of similar mathematical statements. In general, the history of philosophy seems to be a movement from general musings and questions to more concrete discoveries in the hard sciences (physics, math, cognitive psychology) that answer or at least give insight to particular philosophical questions. To illustrate this with a dumb example: "When a tree falls in a forest, and no one is there to hear the noise, does it make a sound?" Of course, from physics, we know that it does, and from Piaget's experiments in cognitive science, we know that the human mind is is born with certain physical expectations wired into its neurons. Scientific developments have a way of gutting the power of philosophical questions (and that is good). Although Heidegger would not doubt rap my knuckles, it is non-the-less time to ask "When can we start updating Heidegger's question with some less-metaphysical ground?"
At this point, an aside is in order (and I can't help but note that most of Heidegger's discourse is a series of irrelevant asides). The popular reading of 'essents' is, of course, 'the universe'. There remains, however, the little difficulty of defining what the universe is: is it that physical thing, consisting of quarks and photons? Is it that discursive thing, consisting of utterances and arguments, statements and communications, from one human to another (surely, if we believe we are made of quarks and photons, then we must also believe that our utterances, indeed, all of 'cyberspace', is firmly rooted in 'the universe', viz. reality. Or do you wish to argue that cyberspace is 'unreal'?) By likewise extrapolation, personal, subjective human experience seems to objectively belong to the very same sphere, assuming, that is, that you believe that I exist. :-) I do not wish to make light of deep subjective questions, such as 'how do I know I'm not dreaming?'; rather, I propose that in order to progress in the traditional scientific, analytic sense, one must do so in the traditional, sober, objective fashion. Along with most of humanity, I take cognitive reality for granted. By extrapolation, I can safely confuse 'essents' with 'the universe' with 'anything that can be thought of, imagined, or discussed'. Whether this keeps one out of the muddy waters of 'category theory' remains to be seen. Thus, the popular misreading is 'why is the universe self-aware'?
To better illustrate the point, consider this nonsense assertion: "Suppose there were essents, rather than nothing, but these essents didn't ask questions." That this is nonsense is demonstrated by the fact that you are reading this: "I think therefore I am" seems to establish (meta-)physical existence, and so of course, it is subjectively and phenomenologically true that the universe is aware of its own existence. But why? The question remains: why? (and, of the scientific question that we ultimately hope to answer, "How?")
Physis, the 'comingness-into-being', the 'manifestation', 'revelation', 'in-sich-aus-sich-hinausstehen', often done through a sheer act of will (an ancient human tradition acknowledged by Heidegger), is not unlike the stuffing of one more guest into another guest-room at the countably-infinite hotel. The cantor slash tells us that we cannot count all the irrationals, even as it leaves us with an algorithm to stuff a finite number of them into the list. In what ways might an act of will be analogous to the (meta-)algorithmic generation of new irrationals by means of the cantor slash? When we 'will things into existence', what might we actually be doing? Note that 'willing into existence' implicitly assumes the need for an immutable past, a malleable present, and an unknowable future. 'Willing into existence' happens in the here and now, and is how unknowable future is transformed into a fixed past.
This, however, begs a question. We know that mathematics lies on shaky foundations, on a visionary perception of the 'truth' of certain foundational axioms. Mathematicians are deeply concerned that their foundational axioms may someday lead to a deduction of of contradictory statements. So we see that mathematics already lives in a Zen-like world of 'just do it': one knows Godel, and moves on. The underpinning eventually depends on visionary perceptions. Where to draw the line?