Cursus Philosophicus Thomisticus, Prima Pars Philosophiae Naturalis

We present for your light and your judgment the first part of Natural Philosophy, which is Thomistic not only according to the doctrine itself—as much as it has been given to us to attain—but in its very order. For in order that we might emulate the theological method of St. Thomas even in Philosophy, and so that the handmaid might learn to fall prostrate in the footsteps of her mistress even as to the very order of arrangement, we have divided this natural science into as many parts as the Summa Theologiae, assigning to each its peculiar matters and treatises, as we note more extensively at the very outset of the book.

Nevertheless, in order that the discussion and illustration of the doctrine itself might be led into the deep (that is, into the depth of disputation) the gust of this labor of ours has perhaps spread itself out rather widely and long-windedly, fully aware that the simplicity and paucity of our intelligence cannot contend with or equal the supreme dexterity of certain others, who, in some brief little book, as if in a ditch, presume to hide or rather swallow up the whole sea of natural sciences rather than explain it.

But we, having professed ourselves to be commentators and expositors in the crafting and writing of books, and not original authors, have attempted so to chart a moderate voyage across this vastest ocean of all nature—a voyage arduous enough in itself and roughened by the difficulties of great questions as if by the waves—that we might neither be wrecked by the whirlwind of brevity nor capsized and thrown overboard by swells too prolix in breadth. But if anyone nauseous should loathe the prolixity, or someone more scrupulous should object to the brevity, he ought to consider that we could not be so restricted as to decline the direct challenge of disputations, nor yet so broad as to touch upon everything in minute detail, given the magnitude of the difficulties and the opposition to the teaching of St. Thomas. Rather we have endeavored to explain the principles themselves such that one might descend to each specific thing and be satisfied in many others matters without a long or tedious demand of attention. He, however, who wishes all his difficulties to be exhausted for him in some book without any labor or meditation, and yet loathes to endure all prolixity in reading, for him I bring forth that sentence from the words of Jerome: No one is compelled to read what he does not want. I have written for those who ask, not for the fastidious; for the grateful, not the envious; for the studious, not the yawning.¹ Fare thee well.