Proofs of God’s Existence

Philo and Soc Sci Essays


In this post, I am going to share Ms. Dua Aeka Uriarte‘s brilliant engagement with St. Thomas Aquinas and Descartes’s proofs of God’s existence as her answer to the take-home essay exam in my class Theodicy. My main reason for doing this is to provide philosophy students some hints on how to write a take home essay exam in philosophy. Ms. Dua Aeka Uriarte is a senior BA Philosophy student at Silliman University. Needless to say, Ms. Uriarte’s paper is indeed an excellent one.


  1. Explain as thoroughly as possible St. Thomas Aquinas’s 5 proofs of God’s Existence. Present your own critique of Aquinas.

 In order to answer the question of God’s existence, St. Thomas Aquinas presented five ways or proofs of His existence in his most notable work, the Summa Theologica. These five arguments draw proof or evidence from man’s experience with the world and are noticeably influenced by Aristotle and his concept of the four causes.

The first argument he had formulated is the argument from motion. After observing objects in motion, man can reach the realization that whatever is currently at motion were once at rest but had changed states when it was moved by something else. This mover was something once at rest as well but was also moved by something else. This line of thought would go on and on until it forms an almost infinite series of concurrent events where the objects are both movers and moved. But if this series of events needed something to begin the movement, then, it is logical to assume that at the very beginning of this infinite series is the first mover, which starts the movement.  St. Thomas Aquinas describes this first mover as the “unmoved mover,” a label which is quite similar to Aristotle’s “prime mover.” Both see this mover as one that is not caused or moved by anything other than itself and is thusly attributed by the theologian to the Christian God.

The second argument is the argument from causation and builds upon Aristotle’s concept of the efficient cause. The main idea in this argument is that every object, action, or event, according to Aristotle, has an efficient cause or an entity or event responsible for its creation or change. Just like how a baby finds their efficient cause in their parents and their parents in their own parents and so on and so forth, St. Thomas Aquinas uses these examples of dependent relationships to show that every person or object in the world has or depends on a creator (efficient cause) and that this creator also has its own creator, and this new creator also has its own efficient cause. This cycle, much like the argument from motion, can go on and on in an infinitely but, according to Aquinas, it should not be so since the series would then never begin.

It is then logical to assume that at the very beginning, there is the existence of a “First Maker” or an “Uncaused Cause,” which, as the name suggests is the efficient cause that is not caused by others or anything but itself. This “Uncaused Cause” is, of course, attributed by Aquinas to the Christian God.

The third argument in Aquinas’ list of proofs is the argument from contingency which necessitates the distinction between “necessary” and “possible” beings. “Possible” beings, simply put, are beings that can be created and corrupted or are beings that can exist and not exist. An example of a possible being is man. Man is a possible being because we have the potential to exist (birth) and the same potential to not exist (death). Plants, animals, and structures, are among some of the other beings included in this category

With this in mind, it is then reasonable to think that since most beings in the world are possible beings, then there must have been a time that they had not existed at all, which means that nothing ever existed. And if there truly was a time of pure nonexistence, then nothing could currently exist because nothingness can only yield nothingness. The only way that our existence at this very moment could be explained, for St. Aquinas, is if there was a being that already exists despite the nothingness of the possible beings.

This being is called a necessary being. Necessary beings, on the other hand, are beings that necessarily exist or are beings that cannot be nonexistent. For Aquinas, there must be at least one necessary being to exist at the very beginning for the rest of the beings to be able to exist and this being is, of course, God.

The fourth argument is the argument from degrees of perfection. This argument makes use of man’s knowledge of perfection and their tendency to judge or evaluate whether an object or person is more or less perfect. This action of judging something to be more or less perfect means that there is a standard that is used for the said evaluation, but how could man ever have such standards unless there is a being that is all-perfect to compare it to? St. Thomas Aquinas affirms the existence of such a perfect being, and says that if any other being would be compared or evaluated against such perfection, they would always be judged as less perfect. He calls this all-perfect being God.

The fifth and last argument in St. Thomas Aquinas’ defence of God’s existence is the argument from final causes or design. Some scholars would also call this argument as the teleological argument. St. Thomas Aquinas once again drew on the notions of causality as presented by Aristotle to justify this argument. The “final cause,” as described by Aristotle is the fourth cause and is one that refers to “the end, that for the sake of which a thing is done.” Some scholars would describe it, rather simply, as the cause that refers to the purpose of which a specific object or entity has been created to fulfil.

Humans and most natural beings in the world have been “designed” to have a purpose and we behave or act accordingly to that purpose. For instance, the bird’s wings behave in accordance to its design which allows it to fly. Human’s talk using our mouths because this is in accordance to our body’s design which allows us to utilize air and various muscles in our body to create sounds.

For Aquinas, if there is some sort of design that is set on our world, then there must be a designer. This designer cannot possibly just be humans or other natural beings themselves as he describes man as imperfect and not intelligent enough to set such a grand design. Some of natural beings, Aquinas tells us, are not even capable enough to know what their end is. The design of the world, therefore, must have been set by a being that is vastly more intelligent than humans and knowledgeable enough to guide them towards their end. This, of course, is God.

These five proofs of God’s existence, during Aquinas’ time, were found to be compelling enough and soon grew to be influential in religious discourses. For some religious denominations, these arguments still remain significant in defence of the Faith up until the 21st century, where most of them have been incorporated into doctrines and statements. But as groundbreaking as St. Thomas Aquinas’ arguments were and are, there is still room for critique.

The main criticism that one can immediately infer from these arguments is the fact that a majority of them remain as assumptions. Though St. Thomas Aquinas did invoke observations from man’s experience with natural phenomena as well as logic to prove his point, there is no concrete way of knowing whether these events do happen in the manner that the theologian-philosopher has described it.  In the case of the first proof, there is no concrete explanation as to whether every single movement in this world can be traced back to one single cause nor is there enough proof to determine that an event  or an object is necessarily moved or affected by the simultaneous movement of another object or entity. In the case of the fifth argument, it is simply too illogical to immediately assume that just because the bird’s wings are aerodynamic or that humans are capable of speech it automatically suggests the presence of both a grand design and of a grand intelligent mind when, in the same paradigm, the notion of spontaneity and adaption exists.

Interestingly, he did speak of this same point in the Summa Theologica as Objection #2 and his response to this response is as follows: “For all natural things can be reduced to one principle which is nature; and all voluntary things can be reduced to one principle which is human reason. Therefore, there is no need to suppose God’s existence.”  Though the reduction does serve the purpose of trying the establish concrete principles where he can root his arguments on, the idea that natural and voluntary things can be reduced into just nature and reason is still an assumption by itself.

It is tempting to think that there is indeed such a connection between the beings in the world, but as far as human knowledge is concerned, these conclusions are merely a product of inference and is not concretely proven.

This then leads to the second point of my criticism. Should a person not be satisfied with the assumptions forwarded by St. Thomas Aquinas and decides to do away with them, then Aquinas’s five proofs will become irrelevant. The arguments would not be able to stand once you remove the assumptions, such as the assumption that the one thing is caused by another or that if the notion of a grand design necessitates the existence of a grand designer, as these are the logical links between his premises. To continue to believe in these arguments without said assumptions, one must somehow either see it in a dogmatic light or ignore contrary logical proof.

Despite these criticisms, St. Thomas Aquinas’ philosophy has withstood time and continues to play a significant role in the development of both the Church and modern theology. By incorporating human experience, logic, and Aristotle in his attempt of proving His existence, he not only formulated five succinct and insightful arguments but he had also brought theology further than what his time had expected.


  1. Explain as thoroughly as possible Descartes’s proofs of God’s Existence. Present your own critique of Descartes.

Descartes’s proof of God’s existence came after he had proven that it is his ability to doubt that proved his very own existence. The argument that culminated in his most famous dictum, “cogito ergo sum,” is what some scholars would call the first certitude in his philosophy. The second certitude is the proof of God’s existence or that he exists despite our doubting of everything else in our immediate world, and Descartes’ argument promptly “starts off” where the first certitude ends. He proves His existence using the idea of perfection.

At this point in his philosophy, it is a fact that man has the ability to doubt everything that surrounds him. Due to the fact that man has this said ability, Descartes believes that he is an imperfect being. But despite his being imperfect, he can still think of perfection and he can still conceive of a more perfect being than himself which is God. This would not make sense because an imperfect being cannot think of or know of perfection and of such a perfect being, that is, unless there is someone or something out there that had given or bestowed upon him this idea of perfection, allowing him to be able to know it or conceive it.

According to Descartes, for man to be able to do that, it must also follow that this being must also be perfect to be able to impart the idea of perfection since it makes no logical sense for an imperfect being to impart knowledge of perfection to anyone else. The only perfect being that can do this is God; and since we can conceive him and know of his perfection-therefore, God exists.

His argument was short, concise and impactful but continued to be logical and sensible. But as well-written and elucidated it is, there remains several points of clarification and considerations. Firstly, Descartes has to defend or clarify whether God is necessarily perfect. In his argument, it is because of our ability to conceive of perfection that necessitated the existence of a perfect being but how will Descartes’ argumentation hold if the very being that impart the knowledge of his existence to man, the imperfect being, is not the perfect being that the philosopher was describing?

If his answer would still be in the affirmative, that God is perfect, it would also be logical to say that it still wouldn’t necessarily follow that man would, each and every time, hold the idea of God as a being that is perfect. Several sects of the faith do believe in God, however, they do not see him as the omni-God or the perfect God but they see him as the imperfect God or a God that suffers and bleeds with them. Atheist can still think of and conceive of God but they see him as a flawed being; a being that isn’t just, that doesn’t listen, and so on and so forth. Man would then still know of God but we then have an imperfect idea of God. Such an idea would make it hard to continue to call that deity “God” seeing as that god would then be seen as a Being that is just as vulnerable and erroneous as man which is the complete opposite to the idea of the Christian God.

Secondly, is man’s capability to conceive ideas of perfection and of God really evidence enough to declare the existence of God? As Descartes himself has said, men are imperfect beings that still use their unreliable senses to gain knowledge and understanding of their world, regardless of whether that knowledge is true or not. It is then reasonable to see man having different or deviant ideas of perfection. In the very first place, it is difficult to get to one idea of perfection seeing as man can think of many ways that perfection can be characterized, so is it really the best idea of concept to use in justifying the existence of a transcendent Being? If man’s ability to know of perfection can lead to the conclusion that there is a being that is more perfect than us, does that also mean that man’s ability to think of and conceive of evil and unjustness also lead to the existence of a perfectly evil and unjust being? If so, wouldn’t that defeat the purpose for his having included the defense of God in his works when it would also defend the existence of His counterpart?

Still, despite the fact that his argument kept being questioned at every possible opportunity, his defense of God’s existence through the consideration of man’s imperfect nature and his ability to conceive of perfection and the idea of God by itself is a testament to his sound and resourceful logic. Considering that this has been conceived of and written in the 17th century, it is a feat then that Descartes’ philosophy continues to find relevance in modern society and thought and that it has paved the way for man’s reconsideration of what truth actually is and how we can attain it.


  1. What is your personal view of God? Does God really exist? If so, what is God for you and how do you know that he exists? If it’s not the case, what do you think of the God of those who believe?

My personal view of God, strangely enough, is one that is quite similar to the one that is held by the Church and those of the Faith. If I were to believe in a god, I could see myself seeing that god to be as kind, loving, patient, merciful, all-knowing, wise and all-seeing as the Christian Omni-God. I do believe that there is nothing quite as reassuring as knowing that there is a Being that out there that watches over mankind, keeps them safe, and constantly looks out for the world’s best interest.

But I, personally, cannot call this God as “perfect”, not because he makes mistakes but simply because I do not think that the word “perfect” can aptly encompass how He is and how he governs over us. I cannot find myself believing in a God that is as “perfect” as the ones that theists describe which is a God that is either too perfect to make a mistake or too kind to do anything evil simply because it is contrary to his nature of perfection. This predominant idea of perfection, if anything, restricts man’s view of God, subjecting Him to the same moral standards as we do other human beings. These moral and ethical norms cannot be applicable to a being as encompassing as a god or God as we have no clear grasp as to what He is truly like. If I were to see my god this way, I would end up having to doubt and defend him every moment of my life.

My personal view of God is that he is a God that is kind, loving, all-seeing, all-knowing, and wise, but he is not perfect. This view is not the kindest of views, nor is it the easiest to accept since this might connote that this God will make mistakes, will make man suffer, will make them wait, but it is also a God that is not constricted by human niceties and can continue working on a “story” that is beyond our comprehension.

With this, I would like to clarify my position. I do not believe that God exists, but this answer warrants an explanation.  If asked to explain why I do not believe in His existence, my full answer would be that, as of now, I have not found reasonable, conclusive proof to say that the Christian God does exist, but this does not mean that I am not open to instances or circumstances that may prove that either He or other divine beings do exist. I am simply an atheist, as of the moment, because I am still in search of reasonable proof or justification that would help me accept the notion of a supreme divine being actually existing and watching over me, as I cannot bring myself to fully dedicate myself in service to a God that I do not personally understand and know.

In regards to the God of the believers, I have little reason to see it in a negative light. As I had mentioned earlier on, most aspects of my personal view of God do not differ from that of the traditional image that had been held and taught by those in the Faith. Theists and I can agree that God is loving, is kind, is wise, is knowing, and is patient. We can both agree that God does have a “grand plan” for us and that He tests mankind using disasters and catastrophes from time to time to see whether or not their faith has not been broken and if they have held on to his teachings.

However, I have realized that, more often than not, some of these believers have misrepresented or have distorted their approaches in explaining their view of God so much that at some points he can be thought of as a contradictory God. For instance, it is difficult to reconcile the idea of a loving God to their depiction of a distant God. It is understandable why this representation continues to proliferate amongst believers since it is a testament to His omnipotence, however, it may also lead to the  implication that He is a God that is either does not want to interact directly with His creations or is one that finds being with his creatures an act that degrades his divinity. Out of all the possible ways that he could assert His omnipotence, why does He choose to create such an inaccessible realm and be distant? If these implications are considered, some may then see the Christian God as one that cannot be treated as a God that is with the people for how can He be with man when the Church and other theists assert that He is in the heavens?

Another example of an approach distorting people’s view of God is the Church’s practice of fear mongering as a teaching method. The use of fear to persuade both non-believers and children to do good deeds and believe in God indirectly paints a picture of Him being unforgiving, vengeful and cold. This kind of practice damages the entire reason that God had allowed man to perform miracles, which is to show that he is kind and loving enough and that he wants you to have faith in him, since people will indeed become believers but they are driven by fear, and not love.

Thus, in summary of all the points that I have raised in this paper, I do not believe that God exists but should he exist, I would view him as a God that is merciful, kind, patient and imperfect. The God of those who believe is, for most parts, in line with my beliefs with the exception of the several misrepresentations that have happened during the development of the Faith, such as the portrayal of a distant and vengeful God.



For more on the proofs of God’s existence, see Philosophy, See also HuffPost,

For students who are new to philosophy, this article may help:



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