9 Contributions Aquinas Made To Theology

In our modern time many have forgotten about Thomas Aquinas. Particularly in protestant evangelicalism, Aquinas is ignored for a more analytic philosophy and even theology, ignoring Aquinas and Aristotle and following down a line of philosophers like Hume, Kant, Kripke, etc. Aquinas, and Aristotle before him, are seen as too archaic. Perhaps many protestant theologians feel he is too catholic? Perhaps many philosophers feel as though anything before the Enlightenment is not worth studying? Aquinas, however, is not only worth studying but he is very relevant for today, even for—and some might argue especially for—protestants. Aquinas even anticipated and answered questions which are still plaguing us today like the mind/body problem, inerrancy, and apologetic methodology. Aquinas has much to offer by way of philosophy, theology and apologetics and he certainly should be studied in depth by any serious student of philosophy and theology.

Aquinas has made many contributions to theology, philosophy and apologetics. His contributions are still relevant today having written on many topics.

Aquinas had a very analytical mind and wrote many books. His most famous works are his Summa Contra Gentiles and his unfinished work, the Summa Theologica. Dr. Norman Geisler points out nine contributions to Christian thought made by Aquinas. As it pertains specifically to theology, we can list at least five relevant topics: Revelation, God, Analogy, Creation, and Anthropology.


Coming from the Dominical order, Aquinas had the utmost respect for Scripture. Since Aquinas was part of the Order of Preachers he was required to teach from the Scriptures one to four times a week. It was also a necessary part of his vocation to remain steeped in Scriptural study. As a professor, Aquinas was also required to read from the Bible and teach his students from the biblical text in a few words using parallel biblical texts. This was a practice known as cursorie.

As such, Aquinas was very well learned in Scripture–to say the least. He contributed many writings. He wrote commentaries on books from the Old and New Testaments, the most famous of which is the Catena aura–meaning the golden chain. The Catena aura is his commentary on the four gospels of which even his most ardent critics praised.

When it comes to the Bible, Aquinas believed that God was the author. He based his doctrine off of 2 Timothy 3:16-17, “All Scripture is breathed out by God and profitable for teaching, for reproof, for correction, and for training in righteousness, that the man of God may be complete, equipped for every good work.”

Aquinas also wrote that the Bible was written by men, calling the human authors “instruments of divine operation.”

Aquinas was also an inerrantist, and unlike most theologians today, he was a total inerrantist–as opposed to limited inerrantists–teaching that ‘it is heretical to say that any falsehood whatsoever is contained either in the gospels or in any canonical Scripture.”

One can also surmise that Aquinas was a conservative in his hermeneutics as is evident in his Scriptural commentaries and principles of interpretation laid out in his commentary on Aristotle’s De Interpretatione (On Interpretation). Suffice it to say, Aquinas was very much on par with modern Conservative-Evangelical theology.

God’s Nature

Aquinas expounds on God’s nature in his writings defending the traditional attributes of God from a Classical Theological position. Modern Christian scholars like Plantinga, Craig and Swinburne hold to a Theistic Personalist view of God which has its complications. Aquinas teaches that God is Actus Purus (Pure Act). This is significant because modern theology teaches a more open view of God, even going so far to say that God has limitations.

Take for example Richard Swinburne in his books Was Jesus God, “Generally it looks as if it is not logically possible for God to know infallibly beforehand what a free agent will do.” He tries to compensate for this by stating, “But since God is omnipotent, it is only because he permits this that we have free will.”

This is unacceptable from a classical theistic standpoint. In relation to God’s actions or activity in creation as well as His relation to creatures Thomas Aquinas, possibly the greatest of all classical theologians, stands in stark contrast here as he states,

Since God is altogether outside the order of creatures, since they are ordered to him but not he to them, it is clear that being related to God is a reality in Creatures, but being related to creatures is not a reality in God. We say it about him because of the real relation in creatures. So it is that, when we speak of his relation to creatures, we can apply words implying temporal sequence and change, not because of any change in him but because of a change in the creatures; just as we can say that a pillar has changed form being on my left to being on my right, not through any alteration in the pillar but simply because I have turned around.

Taken from Brian Davies, An Introduction to the Philosophy of Religion

As Brian Davies points out in his An Introduction to the Philosophy of Religion, “the idea here is that God can act so as to bring about dateable events without himself being part of any temporal process.”

With this knowledge in mind we can eliminate ahead of time the objection that God determines our future actions because by knowing what our future actions are ahead of time he then causes them because if we say God does not know what our free actions are the we deny his omniscience. However, if we say He knows our actions ahead of time or foresees our future actions then this causes another problem.

If we say that God simply “foresees” our actions then our actions would affect God’s knowledge since it is our actions then that cause knowledge in God. Aquinas would state that God changelessly knows what our future actions will be simply because he changelessly knows Himself as the sustainer and Primary Cause of all that exists.


Another contribution that Aquinas made to theology is his teaching on God-talk, or how we use language to talk about God.

As was stated before, God is Pure Act. As Pure Act, God is simple, meaning without any division in His Being. This does not mean that nothing can be attributed to Him. What it does mean; however, is that what is attributed to God can only be done analogically. This is something that even modern Christian theologians and scholars miss. The fact of the matter is we know things about God. Some things we know by revelation, other things we know philosophically, and some we know both ways (via revelation and by philosophical demonstration). We can say things are attributable to God like intellect, will, goodness, etc., even though God is infinite and we are finite.

This does not mean that we are left with some type of agnosticism about God as some modern scholars would claim. It means that we understand that the kind of Being God is, is not the same as we are. God is Pure Act and we are a composite of act and potency. Because of this, we can understand things about God and even attribute names to Him like His freedom, will, etc., because creatures and Creator have act in common. Therefore, we can understand words as the yare defined, but we apply them to God analogically.


When it comes to Creation, Aquinas teaches–in accordance with the Bible–that God is the sole Cause of all that exists. God did not just create the Universe from pre-existing matter, nor did He form creation out of Himself; rather, God created everything ex-nihilo, out of nothing.

Moreover, God is not merely like a Divine watchmaker in the sense that he created the Universe and left it running on its own. As a watchmaker makes a watch and the can step away from the watch leaving it to run. The Universe is not merely a mechanism that can be left running. God is not only the Cause of the beginning of the Universe but also its Sustainer. God is the reason of not only how everything began to be, but He is the sole cause of why everything continues to be.


As we have stated before, God is a necessary Being which is to say God is Pure Act. Contingent beings, Aquinas teaches, are composed of act and potency. The Twenty-Four Thomistic Theses summarizes Aquinas’ teaching this way, “Potency and Act divide being in such a way that whatever is, is either pure act, or of necessity it is composed of potency and act as primary and intrinsic principles.”

Having understood that creatures are composed of act and potency we now turn to human beings specifically. As contingent beings, human beings have act and potency, essence and existence, but human beings are a matter/form unity of body and soul. There is no identity between body and soul in that the body is not the soul and the soul is not the body. They are, however, a unity and while our soul survives the body in death, it awaits reunion with the body until our final resurrection at the end of days.


As we can see, Aquinas has much to offer in the current theological and philosophical discussion. For example, Aquians seemed to hold to a “proto” Sola-Scriptura (Scripture Alone). Catholic theologians are quick to point out that Aquians gave credence to the authority of the Apostles Creed and the Nicene Creed; however, in the Summa Theologiae Ia, I, 8 Aquinas states that when Scripture, “argues conclusively” then its “own proper authority is Canonical Scripture.” Aquinas also says, For our faith rests in the revelation made to the prophets and the Apostles who wrote the canonical books, not on a revelation, if such there be, made to any other teacher.”

Aquinas also contributed to the Classical Theistic view of God and defended it. He was the only one to provide an answer as to how we speak about God without falling into univocal God-talk or equivocal God-talk, but the proper analogical God-talk. Aquinas taught that God created ex-nihilo and that human beings are composed of act and potency with a hylemorphic dualist as opposed to God who is Pure Act. Aquinas is not only relevant for today, but I would argue is necessary to study for any serious student of theology.

*The above was adapted from any essay I wrote titled, What Hath Roccasecca To Do With Wittenburg?


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