6. To these objections I reply that the domain covered by a science has either to do with its material object only, or with its formal object considered from the viewpoint of what determines the object as a thing (ratio formalis quae), but not from that of what determines it precisely as an object of knowledge (ratio formalis sub qua). Now it is on this ultra-formal determination that the specification of the sciences properly depends.

Thus, on the one hand, theodicy, or natural theology, and the theological treatise De Deo Uno have the same material object; while on the other hand the intuitive science of the blessed (the beatific vision) and theology, though differing essentially in virtue of the ratio formalis sub qua, have from the angle of the ratio formalis quae the same formal object or subject,^{8} namely, God simply according to His deity (Cf. Cajetan I, q. 1, a 2, 3, 7). For two sciences to cover the same field, therefore, by no means suffices to put both in the same species. Practical philosophy adequately considered (that is to say, truly apt to guide human action -- from a distance -- without error) and moral theology can cover the same field and have the same object, human acts, and still remain two specifically distinct forms of knowledge by reason of the formal determinant sub quo.

It should be remarked, furthermore, that the subjective faculty or means of knowing and grasping, which in both these cases is reason enlightened by faith constitutes -- just as unassisted reason does in the sphere of purely natural ways of knowing -- a cognitive energy of too wide a generic order to constitute the subjective correlative to the formal determinant which specifies a science. The prudence which is of the Holy Ghost, for example, likewise comes to us from reason illumined by faith, and yet in this case the subjective means of knowing, specifically considered, is the gift of counsel. In the case before us this subjective means of knowing is the theological habitus on the one hand and the habitus of moral philosophy in its perfected state on the other. And it is my contention that although the latter habitus is elevated through its subalternation to theology and thus ceases to be purely philosophic, nevertheless it remains by its very nature in the philosophic order.

{8} These two words, which strictly speaking designate different things, may be used interchangeably here (Cf. John of St. Thomas, Curs. Theol., I. P., q. I, disp. 2, a. 11).