The Influence of St. Thomas
St. Thomas Aquinas holds a special place of honor in Roman Catholicism. To be sure, one can be an orthodox Catholic without following Thomas’ philosophy–indeed, his influence is minimal in Eastern Rite Catholic Churches. And in the Western Church, not everyone follows Thomas. Franciscans, for instance, generally prefer Bonaventure. Moreover, even those who consider themselves Thomists have all manner of disagreements with each other and even with Thomas himself.
Still, Thomas’ influence in the Western Church is hard to overestimate. Catholics refer to him as the Angelic Doctor. In many ways, Thomas is the high water mark of what has come to be called “scholasticism” and “classical theism.” In fact, if you survey the writings on the doctrine of God even by Protestant scholastic theologians after the Reformation, you’ll find that many depend almost entirely on the method Thomas laid out over three centuries earlier.
His influence has continued into the present, following the publication of Pope Leo XIII’s encyclical Aeterni Patris (1879), which called for a renewal of scholastic and Thomistic thought, at a time when its influence had begun to wane. Today, many traditional Catholics, tired of the unfaithful innovations that resulted in the wake of (though not necessarily as a result of) Vatican II, look to Thomas to provide a way forward. Several Thomists have recently criticized ID for having a faulty (if implicit) theology and philosophy of nature, and they have claimed their critique depends on St. Thomas’ philosophy of nature. So it might help the discussion to consider his views briefly.

Thomas was the first Christian theologian to make full systematic use of the Greek and pre-Christian philosopher Aristotle, most of whose works weren’t available for centuries to Europeans after the fall of Rome. But contrary to stereotype, Thomas did not strictly follow Aristotle. His views are actually a sophisticated synthesis of Neo-Platonism and Aristotelianism in light of the biblical witness and sacred tradition. (I’ll show that in more detail in later installments, but it’s obvious on even a causal reading of his Summa Theologica.)
“Cause”
Thomas drew heavily on the distinction between potency and act, which was foundational for Aristotle’s metaphysics. He also used the philosopher’s famous four causes: material, efficient, formal, and final, though he modified them for his own purposes.
Now the way Aristotle and Thomas used the word “cause” can be confusing to modern readers. Simply put, by “cause,” they were referring to positive factors that explain or are responsible for something else. To fully grasp how Aristotle and Thomas understood the four causes, you have to get inside their metaphysical systems. I’m not sure how to do that for readers, at least without a lot of verbiage, so we’ll have to settle for a common translation of these concepts into the modern vernacular: the material cause explains what something is made of; the efficient cause explains where something came from–who or what produced or moved it; the formal cause explains what something is; and the final cause explains the ultimate purpose toward which something tends. For Aristotle, not just organisms, animals, and people, but all physical objects tend toward the perfection of their nature or essence.
In explaining the doctrine of creation, Thomas appeals to all four causes. God is the ultimate cause of everything other than himself, and did not create indirectly through the mediation of angels or other beings. There is one triune Creator, and there are creatures. Every orthodox Christian theologian has affirmed that. But Thomas makes the point in modified Aristotelian language: “Since God is the efficient, the exemplar [a type of formal cause] and the final cause of all things, and since primary matter is from Him, it follows that the first principle of all things is one in reality. But this does not prevent us from mentally considering many things in Him, some of which come into our mind before others” (ST I:44:4).
In his Summa Theologica, Thomas argues that God directly created every human soul and directly made the original body of Adam. He insists: “The rational soul can be made only by creation” (I:90:2). To be clear, he means that each human soul, which is the formal principle of the body, is created directly from nothing: “[I]t cannot be produced, save immediately by God” (I.90.3).
Thomas considers creation ex nihilo to be the pre-eminent meaning of the word “create.” As he puts it: “To create [in the unique sense attributable to God] is, properly speaking, to cause or produce the being of things.” (I:45:6). In other words, God doesn’t just take pre-existing stuff and fashion it, as does the Demiurge in Plato’s Timaeus.¹ Nor does he use some something called “nothing” and create the universe out of that. Rather, God calls the universe into existence without using pre-existing space, matter, or anything else. So when he creates the universe from nothing, God’s creative act is an act in eternity that does not involve changing one thing into another.²
Creation Ex Nihilo and Other Stuff, Too
At the same time, Thomas knows that words can be used in more than one sense. So he says when talking about the nature of the “light” God creates on day one: “Any word may be used in two ways–that is to say, either in its original application or in its more extended meaning” (I:67:1). The same is true with the word “creation.” In the proper sense, it refers to God’s creation of everything from nothing. But in the extended sense, for Thomas, it can refer to God creating, “making,” or “producing” different things on different days–light, the firmament, plants, animals, etc. It can also refer to God changing something he has already created into something else–“fashioning” it, as it were.
For instance, Thomas argues that God did not create Adam’s body from nothing, but created it directly using, as he puts it, the “slime of the Earth”: “The first formation of the human body could not be by the instrumentality of any created power, but was immediately from God” (I:91:2). And God created Eve immediately, but not ex nihilo, using Adam’s rib (I:92:2-4). Similarly, God produces the fish and birds from water. So while clearly using Aristotelian categories, Thomas otherwise adheres to a quite straightforward, literal reading of the second chapter of Genesis. And he quite freely talks about God’s creative activity in several different ways.
In treating creation in general, Thomas holds that everything other than God gets its being from God. Article 1 of Question 44 (in part one of the Summa) answers affirmatively the following: “Is God the Efficient Cause of All Things?” (I:44:1). Thomas goes on to argue that, through his ideas or “exemplars,” which are themselves formal causes, God “is the first exemplar cause of all things” (I:44:3) and the final cause of everything. (In this way, incidentally, he departs from Aristotle, who did not have a view of a transcendent God with pre-existing ideas distinct from particular natural entities).
There’s a complication in Thomas’ view due to his understanding of how God exists in eternity. To put it basically, Thomas thinks that God’s single act in eternity can manifest itself in multiple, different ways in time. While this may sound quite abstract and hard to understand (it is), Thomas clearly believed, because he thought it was revealed in Scripture, that God created the world in six ordinary Earth days. So he distinguishes between God’s initial act of “creation,” his “distinction” of that creation (days one through three) and his “adornment” of creation (days four through seven) (I:65-74). Moreover, he thought that species have remained unchanged since their creation. Here he is following Aristotle, but he no doubt believed that this, too, was a straightforward reading of the biblical text.
He notes the different opinion of Augustine on the days of creation, who treated the days metaphorically rather than as actual, successive days. Augustine also thought God created things potentially rather than actually on these “days.” This made Augustine an outlier among the Church Fathers on these questions. Since Thomas revered Augustine, however, he seeks to give a charitable interpretation and to reconcile the great church father with the bulk of opinion on the other side–insofar as possible. But he doesn’t side with Augustine.
Finally, where the views of philosophers appeared to conflict with the plain reading of Scripture, Thomas was perfectly happy to say: “On the contrary, Suffices the authority of Scripture.”
In this dispute, it’s vital to remember that for Thomas, God both can and does act in the created order in a variety of ways. Certainly he creates ex nihilo–indeed, that’s the purest, most proper sense of the word “create” since it sets God apart from all his creatures–but that’s only part of the story of God’s diverse creative activity. So anything said about Thomas’ view of God’s creative activity, his philosophy of nature or his understanding of causation and teleology, needs to square with what he explicitly says here.
You can read the passages referred to in this post online:
Summa Theologica
Contra Gentiles
References
¹Though, according to some scholars, the Demiurge does not create using pre-existing matter, but rather pre-existing space.
²See, for instance, Thomas Aquinas, Summa contra Gentiles 2:17, in which he spells out the doctrine of creation: “God’s action, which is without pre-existing matter and is called creation, is neither a motion nor a change, properly speaking.” Notice that he says “properly speaking.” That’s because he elsewhere describes God doing all sorts of things within nature, using pre-existing material. A faithful interpretation of Thomas’ views cannot isolate this one statement from everything else that he says on the subject.