An Analysis of Thomas Aquinas and his Natural Theology

Natural theology, as defined by Thomas Aquinas, is the study of God and His attributes purely apart from divine revelation; that is to say, a study of God based on reason alone. The things learned by this method Aquinas calls, “preambles,” to faith:

“The existence of God and other like truths about God, which can be known by natural reason, are not articles of faith, but are preambles to the articles; for faith presupposes natural knowledge, even as grace presupposes nature and perfection the perfectible.” (Thomas Aquinas, Summa Theologica, Article 2, Reply to objection 1.)

That statement is an overview of Natural Theology, which must not be mistakenly seen as the only kind of theology or the only kind Aquinas believes is necessary. On the contrary, Aquinas defined “Sacred Doctrine” as the attributes and knowledge which God Himself can give. Sacred Doctrine consists of things of God which no human reasoning can begin to understand, and Natural theology consists of the things of God which human reason can begin to understand.

Having established both of these doctrines, the question becomes: which is more important, and in what order should they be pursued? This point is a little more difficult; the ultimate goal of natural theology is to prove the existence of God by pure human reason, while Christianity is based in faith in that which cannot ultimately be proven, and so the two appear to be mutually exclusive.

“…when natural theology is successful it does not provide any grounds for faith in any strict sense of grounds. That is, if natural theology succeeds in its initial task, to prove the existence of God, no de fide truth follows from this as a consequence. If it did, the de fide truth would be transformed into a known truth … (Ralph McInerny, “On Behalf of Natural Theology,” in Being and Predication (Washington, DC: The Catholic University of America Press, 1986), p. 251)

It appears, then, that the question becomes as much of a definition of “faith” as an explanation of how two apparently opposing doctrines can exist with each other. The concept of “faith,” as a blind leap in the dark appears to be where Aquinas is leaning here; a simple belief in that which cannot be seen or proven, for if it is proven then faith is not needed. However, since the definition of a “leap in the dark,” does not fit with Biblical definitions of faith, an examination of the definition of “faith,” is necessary:

“Faith in the biblical sense is substantive, based on the knowledge that the One in whom that faith is placed has proven that He is worthy of that trust. In its essence, faith is a confidence in the person of Jesus Christ and in His power, so that even when His power does not serve my end, my confidence in Him remains because of who He is.” (RaviZacharias, “Jesus Among Other Gods: The Absolute Claims of the Christian Message,” Thomas Nelson Inc, 2002)

“Though He slay me yet will I trust Him…” (Job 13:15, “Holy Bible,”)

We can see that Biblical faith is not a mere belief, will to believe or blind belief in a lack of evidence; contrary to that it is trust by experience and through proof. Aquinas’s definition seems to err more on the side of pure belief, and this is the cause for his concern. Thus, natural theology would appear to be at odds with a belief system in which faith is defined as just belief in that which cannot be proven.

The weakness of Aquinas’s system, therefore, was the thought that if God could be proven, faith would no longer be needed; this view, when examined in light of a Biblical understanding of faith, is false.

Having a proper understanding of both Sacred Doctrine and faith is key to refuting the Thomistic belief that a doctrine which can be known cannot be believed; it is clear that with a Biblical understanding of faith the opposite is true. However, the medieval mode of theology, with faith before understanding clearly colored Aquinas’s view of theology:

“Nor do I seek to understand that I may believe, but I believe that I may understand. For this too I believe, that unless I first believe, I shall not understand.” (Anselm ofCanterbury, “The Devotions of Saint Anselm ofCanterbury,”)

However, as stated above, knowing and believing are only exclusive to each other if the definition of faith takes on clearly un-Biblical connotations. Neither can be seen to be superior to the other; without a personal trust, Christianity is mere intellectual belief, and without reasonable knowledge there are little grounds for faith.

God can, then, be both known and believed in a purely Biblical sense. There are attributes of God that can be known through natural theology and there are attributes that can be known through Divine Revelation only; but neither need be exclusive to the other, indeed, the two are meant to work in tandem:

“…Love the Lord your God all your heart and with all your soul and with all your mind and with all your strength….” (Mark 12:30, “Holy Bible”)

From a Biblical standpoint no faculty is exclusive to the other, and the above statement is confirmed that faith and reason are to work together. Aquinas certainly didn’t dismiss faith as unreasonable or reason as incompatible with faith, but his limited definition of faith forced him reduce faith a more blind belief , which practical and defendable to Aquinas is not an entirely Biblical model.

The conclusion reached is therefore twofold: natural theology and Sacred Doctrine are to work in tandem and not merely picking up where one leaves off; and that a proper understanding of faith is necessary to reconcile the seeming differences and limitations of faith, natural theology, and reason.


Aquinas, Thomas, Summa Theologica. B&R Samizdat Express. 2009. E-book.

McInerny, Ralph “On Behalf of Natural Theology,” in Being and Predication. Washington,DC: TheCatholicUniversityofAmericaPress. 1986. Print.

Zacharias, Ravi. Jesus Among Other Gods: The Absolute Claims of the Christian Message. Thomas Nelson Inc, 2002. Print.

Anselm of Canterbury. The Devotions of Saint Anselm of Canterbury.  New Century Books. 2010. E-book.

Quest Study Bible. NIV.Michigan. Zondervan. 2003. Print.


7 thoughts on “An Analysis of Thomas Aquinas and his Natural Theology

  1. Omar March 25, 2013 / 11:28 am

    I think you have completely misunderstood Aquinas’ notion of faith.


    • whitefrozen March 26, 2013 / 5:59 pm

      Perhaps – but I tend to think I’m representing him accurately. Could you expound?


  2. Omar April 2, 2013 / 12:49 am

    Sure. And I didn’t mean to sound so abrasive last time, so my apologies. You have, in my opinion, misunderstood what Aquinas means by faith. Faith is not a leap in the dark. It is the certainty of an axiom that can’t be proven to be true by the intellect. This doesn’t mean that Aquinas thinks it is leap in the dark. To the Christian, that creation existed (this is an article of faith, so I’ll use it as an example) isn’t something he must blindly accept, for Aquinas. The Christian KNOWS it to be true, perhaps even more truly than he knows the physical world, because it has been revealed to him. It simply isn’t known the way something actualized is, because the world of actuality can be contained by the intellect, while the divine truths of faith transcend our mode of understanding. But it is still known. To the Christian, conviction in divine things requires no leap.

    But, more problematically, I’m confused about how you view Aquinas’ system. Aquinas doesn’t think natural theology and sacred doctrine run past each other. For Aquinas, the question of which is more important doesn’t make sense. “Faith presupposes knowledge.” Faith implies something is known which is believed. But I don’t think that that “something known” is divine revelation. I think it includes natural knowledge. Aquinas Five Proofs take us to the limits of the physical world, the first mover, the first efficient cause, etc. It takes us to that than which no greater can be thought, to the limits of motion and causality and hence to the limits of the world of sense. And this he calls natural theology, whose axioms are derived at through natural philosophy. But Aquinas makes natural theology “the handmaiden” of sacred doctrine, for where the former ends, the latter begins. Natural theology gets me to the Prime Mover, like Aristotle, but where the limits of motion end, Prime Mover, sacred doctrine begins–that is, that the Prime Mover is also God. But since God extends beyond Prime Mover, beyond the world, no amount of natural reason, can get us to the truths of sacred doctrine, because the former is contained by the natural world while the latter is not. Does this mean that to KNOW the truth of sacred doctrine requires a leap? Nope. Aquinas spends the Summa trying to show that sacred doctrine isn’t incompatible with natural theology, or natural philosophy in general; but ultimately, Aquinas admits natural reason can never be enough to push you towards conviction of anything beyond. Only faith can do that. BUT, this faith is conviction that the truth of divine revelation is what is the case. And that can ONLY come about through grace. That’s because I can’t just passively one day believe in the trinity; I have to actively be convinced that it is the case, but I can’t be convinced through natural reason, since, again, reason can’t get me to accept divine revelation, because then otherwise divine revelation wouldn’t be divine but a byproduct of reason, totally grasped by it. Therefore, faith, for Aquinas must be a conviction of things not seen conferred through grace, not blind acceptance.


    • whitefrozen April 2, 2013 / 5:00 am

      I’ll try and reply to this come the weekend when i have more time – but your comment is a very astute one.


  3. Jacinto August 1, 2013 / 11:08 pm

    I needed to thank you for this excellent read!! I definitely loved every bit
    of it. I’ve got you book marked to look at new stuff you post…


  4. Justin Rosenberger August 15, 2015 / 3:58 pm

    I have a question on regards to faith. According to scripture ‘faith’ is a gift. Do unbelievers exercise faith and if so how if it is a gift? Some have stated that it is a ‘blind faith’ or false faith not actual faith but then what is it and why is it called faith at all? Ive looked at the definitions of blind faith and many seem unsound. Do all have faith but are unable to place it in Christ due to the noetic effects of sin until enabled by grace making it a gift? Hopefully someone can help reconcile what scripture says and what I’ve heard and read. Thanks


    • whitefrozen August 15, 2015 / 4:21 pm

      Good questions – faith is indeed a gift! But to quote Aquinas, God is a most liberal giver of gifts! Any faith that a person has in God has its origin in God, but at the same time this doesn’t diminish the role of the person in salvation (I’m a synergist and believe that salvation is a process in which we cooperate with God).

      I wouldn’t tie a lack of faith primarily to the noetic effects of sin, since faith isn’t something that’s primarily epistemic a working of the mind (though both of those have their place in faith).

      Hopefully that is something close to what you’re looking for – if not, let me know and I’ll be glad to clarify.


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