That's the conclusion drawn by Eastern University philosophy professor, R. J. Snell, about some of the Reformed critics of the Manhattan Declaration. In an essay entitled, "Bad Reason and the `Manhattan Declaration,'" Professor Snell writes:
In issuing the “Manhattan Declaration,” Christian leaders across the nation declared their intent to stand for the dignity of the unborn and the institution of marriage even up to the point of civil disobedience. Unsurprisingly, this declaration has spurred much commentary, not all of it sympathetic. One could predict the standard objections from groups and persons committed to the culture of death, but more noteworthy are objections rising from a camp one might expect to agree with the document: namely, a certain kind of conservative Protestant, often, although not always, of a strongly Calvinistic tendency.
One might expect this group to value traditional marriage, oppose abortion and embryo-destructive research, and defend religious liberties strongly, and they do, and yet many in this group have reacted quite negatively to the document. The reaction intensified, at least in the blogosphere, after a New York Times Magazine piece on Robert P. George, one of the leading signers of the declaration.Some of this is the usual antipathy towards Roman Catholicism, which remains severe enough to prompt even a signatory like Dr. Albert Mohler to feel the need to explain his association with the document. The main intellectual objection is precisely the one mentioned in the Times piece, namely, “that [George] puts too much faith in the power of reason, overlooking what Christians describe as original sin and what secular pessimists call history.” The notion that the natural law forgets sin and thus depreciates the necessity of Christ and the supremacy of Scripture is an old one, to be sure, and is a common objection raised against the ethics and theology of Thomas Aquinas by this same group of Protestants. For example, James White states that George’s position is “a direct refutation of the biblical view of the supremacy of divine revelation and the corruption of human reason through sin,” and Phil Johnson claims “the biblical truths of original sin and human depravity [pose] a fairly fundamental challenge to Robert George’s notion that society can be won to righteousness through human reason alone.” And these are among the more moderate objections. The influential Protestant apologist Francis Schaeffer spoke for many when he characterized Aquinas as believing “the will was fallen or corrupted but the intellect was not affected.”
Certainly Thomas held that the first principles of the natural law could not be erased from the human being (ST I-II 94. 6), and neither did sin fundamentally negate human nature, for if human nature were to be essentially changed by sin then our first parents were of a different species before and after the first sin. A nature cannot change essentially without changing the essence of a being, after all.
But only a wooden and uncharitable reading of Aquinas stops here, for Aquinas has a sophisticated view on the question. He holds that the prelapsarian human was endowed with the grace of original justice, a rectitude whereby reason is subject to God, the lower human powers subject to reason, and the body subject to the soul. Such a person would not sin because he or she is properly ordered; without concupiscence, the unfallen human would always follow the dictates of right reason. Original sin, among other consequences, deprives the human of this original justice, destroying the harmonious relation of human powers to each other and to God.
Since the will is for Aquinas a rational appetite, the will is directed to the good of the whole person rather than to some power or part of the person. While a particular appetite, say for food or sex, seeks only its particular satisfaction, the will integrates and directs all these competing desires into a whole, into a human act, which is why humans can, for the sake of their own and the common good, control their desires to consume too much food or fornicate with this or that person. Particular appetites are directed and placed in order by the rational appetite.Given original sin, the rational appetite is inordinate and can act counter to right reason. We do disobey the divine mandate, we do allow lower appetites to dominate reason, and we do allow the goods of the body to triumph over the goods of the soul. Further, given original sin and the loss of human integrity and rectitude, we do suffer what Thomas calls the wound of ignorance, that is, we can voluntarily ignore truth and the desire for truth. We can, and do, act in cunning fashion, whereby reason is bent to devise new and clever evils in service to inordinate desire.
There is no cheery optimism in Aquinas with respect to reason. The human is disordered; one might even say we suffer a totality of depravity since not a single human capacity or function remains in the state of original justice. Yes, humans are utterly messed up, but they are still human beings, and as human beings, as rational animals, they still possess the natural law, for to lose the natural law would be a loss of humanity, actually to become a beast. Not, that is, to act bestially—humans do so—but to be a beast. And this has not happened, since original sin does not change our essence—nor could it. The basic human goods remain the same basic human goods for Adam and for Hitler, and the flourishing of human persons qua persons has not changed. But sin does change our willingness to function as we ought, as we can all attest.
There is, then, no contradiction between the natural law and original sin, at least as understood by Thomas Aquinas. The “Manhattan Declaration,” therefore, remains the declaration of cosmopolis, for insofar as the declaration is reasonable it is reasonable for all, even us sinners.
For more on St. Thomas and his view of the effect of sin on human nature, see this section of the Summa Theologica. Here is an excerpt:
Article 2. Whether the entire good of human nature can be destroyed by sin?
Objection 1. It would seem that the entire good of human nature can be destroyed by sin. For the good of human nature is finite, since human nature itself is finite. Now any finite thing is entirely taken away, if the subtraction be continuous. Since therefore the good of nature can be continually diminished by sin, it seems that in the end it can be entirely taken away.
Objection 2. Further, in a thing of one nature, the whole and the parts are uniform, as is evidently the case with air, water, flesh and all bodies with similar parts. But the good of nature is wholly uniform. Since therefore a part thereof can be taken away by sin, it seems that the whole can also be taken away by sin.
Objection 3. Further, the good of nature, that is weakened by sin, is aptitude for virtue. Now this aptitude is destroyed entirely in some on account of sin: thus the lost cannot be restored to virtue any more than the blind can to sight. Therefore sin can take away the good of nature entirely.
On the contrary, Augustine says (Enchiridion xiv) that "evil does not exist except in some good." But the evil of sin cannot be in the good of virtue or of grace, because they are contrary to it. Therefore it must be in the good of nature, and consequently it does not destroy it entirely.
I answer that, As stated above (Article 1), the good of nature, that is diminished by sin, is the natural inclination to virtue, which is befitting to man from the very fact that he is a rational being; for it is due to this that he performs actions in accord with reason, which is to act virtuously. Now sin cannot entirely take away from man the fact that he is a rational being, for then he would no longer be capable of sin. Wherefore it is not possible for this good of nature to be destroyed entirely.
Since, however, this same good of nature may be continually diminished by sin, some, in order to illustrate this, have made use of the example of a finite thing being diminished indefinitely, without being entirely destroyed. For the Philosopher says (Phys. i, text. 37) that if from a finite magnitude a continual subtraction be made in the same quantity, it will at last be entirely destroyed, for instance if from any finite length I continue to subtract the length of a span. If, however, the subtraction be made each time in the same proportion, and not in the same quantity, it may go on indefinitely, as, for instance, if a quantity be halved, and one half be diminished by half, it will be possible to go on thus indefinitely, provided that what is subtracted in each case be less than what was subtracted before. But this does not apply to the question at issue, since a subsequent sin does not diminish the good of nature less than a previous sin, but perhaps more, if it be a more grievous sin.
We must, therefore, explain the matter otherwise by saying that the aforesaid inclination is to be considered as a middle term between two others: for it is based on the rational nature as on its root, and tends to the good of virtue, as to its term and end. Consequently its diminution may be understood in two ways: first, on the part of its rood, secondly, on the part of its term. In the first way, it is not diminished by sin, because sin does not diminish nature, as stated above (Article 1). But it is diminished in the second way, in so far as an obstacle is placed against its attaining its term. Now if it were diminished in the first way, it would needs be entirely destroyed at last by the rational nature being entirely destroyed. Since, however, it is diminished on the part of the obstacle which is place against its attaining its term, it is evident that it can be diminished indefinitely, because obstacles can be placed indefinitely, inasmuch as man can go on indefinitely adding sin to sin: and yet it cannot be destroyed entirely, because the root of this inclination always remains. An example of this may be seen in a transparent body, which has an inclination to receive light, from the very fact that it is transparent; yet this inclination or aptitude is diminished on the part of supervening clouds, although it always remains rooted in the nature of the body.
Reply to Objection 1. This objection avails when diminution is made by subtraction. But here the diminution is made by raising obstacles, and this neither diminishes nor destroys the root of the inclination, as stated above.
Reply to Objection 2. The natural inclination is indeed wholly uniform: nevertheless it stands in relation both to its principle and to its term, in respect of which diversity of relation, it is diminished on the one hand, and not on the other.
Reply to Objection 3. Even in the lost the natural inclination to virtue remains, else they would have no remorse of conscience. That it is not reduced to act is owing to their being deprived of grace by Divine justice. Thus even in a blind man the aptitude to see remains in the very root of his nature, inasmuch as he is an animal naturally endowed with sight: yet this aptitude is not reduced to act, for the lack of a cause capable of reducing it, by forming the organ requisite for sight.