“In Aquinas there had been no question of a supernatural order ‘added’ to nature. For him, the term ‘supernatural’ referred to the means for attaining the one, final end for which our natural powers no longer suffice. God himself is called agens supernaturale, not to separate the order of grace from that of nature, but rather to distinguish the order of the Creator from that of creation (in which nature and grace appear together). Nature itself thereby becomes the effect of a ‘supernatural’ agent. The term supernatural would not begin to refer to an order of grace separate from the order of nature until in the sixteenth century man’s ‘natural’ end came to be conceived as distinct from his revealed destiny. Thus, St. Thomas’s sixteenth-century commentator, Sylvester of Ferrara, interprets his master’s position as if it separated the reality of nature from that of grace. If God were man’s ‘natural’ end to be acquired only in a ‘supernatural’ way, he argues, we would have a conflict that is not conveniens between nature and its goal. Yet for Aquinas nature is not an independent reality endowed with a self-sufficient finis naturalis. . . .
“The nominalist theologies which came to dominate the fourteenth and fifteenth centuries destroyed the intelligible continuity between Creator and creature. The idea of an absolute divine power unrelated to any known laws or principles definitively severed the order of nature from that of grace. A nature created by an unpredictable God loses its intrinsic intelligibility in favor of the mere observation of actual fact. Nor does creation itself teach us anything of God beyond what this divine omnipotence has revealed in Scripture. Grace itself became a matter of divine decree unmeasurable by human standards and randomly dispensed. Detached from its transcendent moorings, nature was left to chart its own course. The rise of the supernatural signaled the loss of an intrinsically transcendent dimension in nature and the emergence of a profound distrust of that nature on the part of theology. The delicate balance was permanently disturbed. The distinction between God’s potentia absoluta (what he can do, if he chooses to do it) and the potentia ordinata (what he actually does) had originated in the eleventh century and had become universally accepted to preserve the idea of God’s total freedom in creation. Nominalist theology had extended its meaning by freeing divine omnipotence from any limits other than internal contradiction. The resulting increase in opposition between an unlimited divine power and a wholly contingent world order conveyed to distinctions which previously had been no more than rational abstractions a reality status they had never possessed before. Among them was the idea of a pure nature, that is, nature conceived without any supernatural destiny to be attained in the order of grace. As the term had been used in St. Thomas and in thirteenth-century Scholasticism, ‘nature’ had been a theological concept: it referred to a concrete existing reality, either in the prelapsarian state of grace, or in the condition after the fall. As theologians commonly used it, ‘nature’ was no longer human nature in its original state, but a transformed nature that had not remained untouched by sin and grace. Hence the original state of innocence could not serve as the norm, nor were such concepts as natural law based upon it.
“The concept of pure nature, however, that emerged between the fourteenth and the sixteenth centuries overruled those distinctions elevating an abstract idea derived from the theory of God’s potentia absoluta into a real entity. Though claiming to be independent of the historical stages of the fall and redemption which theology had traditionally distinguished, from a theological point of view, its very bracketing of those stages introduced yet another, albeit artificial, historical concept. When later ethical and political philosophies adopted this concept as a theologically neutral basis for speculation, they did, in fact, build upon a negative theological concept. . . .
“[O]nce the concept of pure nature became detached from its hypothetic context (within the idea of a potentia absoluta) and acquired an assumed reality in its own right, it provoked a new, wholly unprecedented attempt to establish a science of God on purely natural grounds. If ‘nature’ could be understood independently of revelation, so could the transcendent cause of that nature to the extent that it was actively operative in that nature. Natural theology came to occupy the same independent position vis-à-vis revelation which ‘nature’ took with respect to what henceforth was to be called the ‘super-natural.’”
—from Louis Dupré, “Nature and Grace: Fateful Separation and Attempted Reunion,” in David L. Schindler, editor, Catholicism and Secularization in America: Essays on Nature, Grace, and Culture (Communio Books, 1990)