According to Heidegger, this running ahead in resoluteness of being-toward-death is what makes my being possible, for death is the most extreme possibility of my existence, my “ownmost potentiality of being [das eigenste Seinkönnen]”. At stake for Heidegger, then, is to conceptualize death not as pure nothingness, but rather as pure possibility.
Key in understanding Heidegger is a conception of death not as a function of mortal finitude, but as a making-possible. Death is not the negation of possibilities, but is the most profound, originary possibility.
"...as a futural possibility, being-toward-death is nevertheless what makes the present possible."
This is the best brief exposition of resoluteness, as authenticity, I am aware of. I cannot begin to guess how welcoming someone not already familiar with MH might find this, but it clarifies and relates some of S&Z's core concepts.
I was hoping Nadal might have more to say about possibility and impossibility. True, his analysis brings those together for authenticity. But are there some other more ontic and tactical implications for the way we use those two concepts? I don't have any. I only recall that as I have written for myself, I have wondered if more is available to be disclosed about possibility vis a vis impossibility. I am not looking for any magic tricks or mere cleverness, which MH's combination leaves open to temptation.
I recall Dylan's lyric about being taught, "You can do what's never been done. You can win what's never been won" as technicity's spill over. Instead, MH seems to sing, "Let it be," without the Beatles' conventional context. What is there for us to see, if anything, in possible impossibilities if we learn to look?
Thanks for the comments and for the repost. I am currently working on Derrida's Aporias, and your question regarding possibility and impossibility will help guide how Heidegger is taken up in that text.
I have now read belate's previous paper on S&Z and the Letter on Humanism. I am similarly impressed with its ability to very concisely lay out MH's arguments. I had to write a final exam on Brief and got an A+ without even approaching the thoroughness of belate's paper.
Both amount to as good an overview of MH up to Brief as I have seen. They are what you pass along to folks who inquire about the early MH.