"In other words, only pride --which is a word we use to describe an attitued that intends to turn away from God--makes sin in the first place into the definitive wrong that it is.
Consequently, the less the concrete deed contains the element of "pride" and the more cupiditas it has, the less the guiltiness of the action. But the more spiritual a human being is, that is, the more he has rendered himself immune to the seductions and charms of the sensible world by living a life of self-abnegation and disciplining his will, the more he can now commit the offense, the sin of unadulterated hybris and blatant pride. Only if all the powers of my being obey me does the question suddenly occur to me: whom do I myself now obey?
This leaves us with an unsettling conclusion: only a purely spiritual being could become guilty in this extreme sense. Of course the philosopher, qua philosopher, has no competence to speak of angels and their sin. Nonetheless, we can learn something of philosophical import about the essence of human guilt when theology tells us that the first sin of the angels could only have been the sin of pride."
"At first hearing, Nicholai Hartmann's own answer [to the question of original sin] sounds quite plausible: "There is no freedom for the good that would not be at the same time freedom for evil." But on further reflection we see how this statement introduces an impermissible simplification into the argument. Were this thesis true, then God would not be free(nor, for that matter, would the person who has attained final fulfillment, the saint in heaven--a category that only the believer can be convinced of).
In any case, in its long history the Western tradition has conceived of the problem differently from Mr. Hartmann. Thomas Aquinas speaks only as one of its witnesses when he says that to be able to sin is indeed a consequence(De Veritate 24,3 ad 2), or even a sign of freedom, quoddam libertatis signum(De Veritate 22,6), but "it does not belong to the essence of the free will to be able to decide for evil."(De Veritate 24,3 ad 2; Commentary on the Sentences 2d; 44,1,1 ad 1) "To will evil is neither freedom nor a part of freedom."(De Veritate 22,6) In other words, the inability to sin should be looked on as the very signature of a higher freedom--contrary to the usual way of conceiving the issue."
And here's a review from elsewhere in the blogosphere.