Original Sin and Christian Philosophy II: Presuppositions

As the title indicates, this post is part of a work in progress. Our project is to work toward a philosophically precise articulation of original sin, especially its nature and extent (and effects. The reader would do well to skim Original Sin & Christian Philosophy I). Thus far, I’ve turned up two well-written and informed articles relevant to the topic at hand. They are “Original Sin and Christian Philosophy” by Paul Copan, and “The Metaphysics of Original Sin” by Michael Rea (this post is heavily influenced by the latter). As always, please mention any others you recommend in the comments.
Obviously, I hold more than these four presuppositions; I’m only troubling myself with these four. Throughout this discussion I will assume the following:

(S1) All human beings (except, at most, four) suffer from a kind of corruption that makes it inevitable that they will fall into
sin, & this corruption is a consequence of the first sin of the first man.

And

(S2) All human beings (except, at most, four) are guilty from birth in the eyes of God, and this guilt is a consequence of the
first sin of the first man. (Rea, 1).

Now, the doctrine of original sin (DOS), I believe, includes both of these assumptions; if you lack either one, you aren’t, in my opinion, dealing with DOS. It is significant to note, however, that one may accept only (S2) as one’s DOS. What of these; are each acceptable?
Scripture supports the universality of human corruption as viewed by (S1) & (S2) above (see esp., Ps 14, 130:3, 143:2; Ecc 7:20; Is 53:6; Rom 3:9ff, 23, 5:12 ;Gal 3:22 ;Eph 2:3; 1 Jn 5:19). Even in the verses which do not explicitly do so, the universality of sin is assumed (Erickson, Christian Theology, 641). Consider also the reality of death as proof of this understanding of DOS: death is the explicit & direct result of sin, we all die (known from common experience), thus we are all affected. So, I accept the universality of DOS. Please note that while I am affirming that Scripture teaches we are connected to Adam’s sin, that is all I am presently doing; we have thus far said nothing of just how we are so connected. Also, as Copan notes: “We should distinguish between damage or consequences for one’s sin and the guilt of one’s sin. For example…the consequences of one man’s sin affects (the) well-being of the entire community” (p. 15, cf. Joshua 7 & 2 Sam 24:17).

Rea continues on to embrace

(MR) A person P is morally responsible for the obtaining of a state of affairs S only if S obtains (or obtained) and P could have
prevented S from obtaining (Rea, 3).

I am inclined to agree with him that this seems intuitively true; upon reflection I cannot disagree with it. But if we accept DOS, then it seems we have a problem with accepting (MR). Rea continues on to (successfully, I think) reconcile these two in his paper. His task frequently takes him out of the scope of ours, but along the way he is able to shed much light on our project. At any rate, if you are willing to flush (MR), then you will probably not enjoy the ensuing discussion. I might also recommend that you look a bit further into the issue, but in the end I suppose you are entitled to think whatever you like. Of course, many in the Reformed tradition do just this—they reject (MR).

I will also assume a libertarian account of human freedom. I realize there is much debate surrounding such a claim, but it is not my intention to entertain that debate in much detail here (but I look forward to doing so in future posts!). So, unless it absolutely infuriates you that I claim such a position, please refrain from promoting that debate for now.

Finally, I’d like to reiterate the importance of presuppositions (without launching a full-on Intro to Phil lecture). They’re important, trust me. I have not identified them all, in fact, I’m confident in my inability to identify every one of mine (a start would be the existence of God, an affirmation of certain of his qualities such as justness, and much more besides), but I think I’ve covered the essentially relevant ones. I know this is a short post that doesn’t really get into the meat of the issue, but I think it’s worthwhile for us consider these things first. More to come.