Spanning from early Christian Thought to contemporary Christianity, theistic proofs have been greatly utilized to rationalize and encourage the belief in the existence of God, yet there are inherent limitations in these proofs due to their reliance on human reason, the paradox of attempting to comprehend the so-called inconceivable, and finally, the inaptitude to address the problem of evil, all of which demonstrate that we cannot know the unknowable and definitively prove God’s existence. It is worth noting what I perceive as simple contradictions within the question itself. The definition of to “prove” according to the Oxford dictionary, is “to demonstrate the truth or existence of something by evidence or logic.” (Oxford Dictionary 2024) While the definition of faith, which is the fundamental attribute of belief in God, is “A strong belief in the doctrines of a religion, based on spiritual conviction rather than proof.” (Oxford Dictionary 2024). With this, the answer to the question; ‘Can we know the unknowable and prove God's existence?’ is unambiguously not something that can be done, nor should be. Theistic proofs were originally a topic of discussion for those who are believers in Christ. Anselm and Aquinas, the primary theologians responsible for theistic proofs, were under the assumption that their audience had no doubt in the existence of god, and the historical purpose of these proofs were to rationalize god, not prove to non-believers. On the contrary, this could be perceived as simply a limitation rather than an error, which is the assumption under which I will continue.
Human reason is vital to many parts of religion. It is the basis of conversation and the only reliable consistency throughout human history. While it is an inherent guarantee, this does not constitute its use when defending God's existence. Human reason is subject to error, inconsistency, and bias, therefore, theistic proofs based on such could be unreliable or unconvincing. For instance, Thomas Aquinas’s cosmological argument is one that reads as so; “P1. We observe motion./ P2. Motion is the actualization of a thing’s potential to be in motion./ P3. A thing can only come to be in motion by being moved./ P4. A mover must be something that is actual./ P5. A thing cannot move itself./ C1. So, all things in motion must have been moved by something else./ P6. If there were no first mover, there would be no motion now./ C2. Therefore, there must be a first mover which must itself be unmoved (pure actuality). That thing we call God.” (Aquinas 1911-1925) While many fallacies are apparent here, I will focus on the contradiction present in premise six, as it demonstrates circular reasoning. The premise that states if there were no first mover, there would be no motion assumes there must be a first mover, which is the conclusion the argument is working to prove. This is a concept highlighted by Aristotle in 350 BCE in “Prior Analytics” where he expressed that circular reasoning is not a demonstration of proof, as it should provide new insight as the argument progresses. Here, the conclusion is contained within the premise, preventing readers from obtaining new knowledge (Aristotle 1969). This spotlights the hindrance of human reason within theistic proofs; an error in the premise of one of Thomas Aquinas’s most famous works. The function of Aquinas’s theistic proof does not aid humans in knowing the unknowable due to its contents containing circular reasoning, which is an error most prominent when relying on human reasoning.
Supplementary to this, theologians encounter the paradox of attempting to comprehend the alleged inconceivable. This concept is somewhat parallel with reliance on human reasoning and how it is inherently limited due to the inconsistencies and biases, as it poses the question of human language and its limitations. To punctuate this, the incomprehensibility of God is a rather accepted and agreed upon notion throughout all christian denominations. With this, there are two approaches, theologically, regarding this topic, the first being the “via negativa” way of speaking about god. Via negativa focuses on what god is not, emphasizing the mysterious element of God's nature. For example, saying ‘god is not finite’ or ‘not limited by space or time.’ (Murphy 1996) This approach is one that recognizes God's transcendence, yet it is still an attempt to rationalize God, which again, is the objective when utilizing theistic proofs. Because of this, another question presents itself; is the use of terminology, questioning, and discussion purposeless, as God is “unsearchable” according to scripture. Here are a few places where this is apparent; “Oh, the depth of the riches and wisdom and knowledge of God! How unsearchable are his judgments and how inscrutable his ways!" (Romans 11:33, English Standard Version Bible) as well as, “Behold, God is great, and we know him not; the number of his years is unsearchable." (Job 36:26, English Standard Version Bible). If one continues with this notion, the use of theistic proofs in general would serve zero purpose, again, having no contribution to understanding the “unknowable.”
The limitations of theistic proofs go beyond reliance on human reason and the issue of inconceivability. There is also the prolonged inaptitude to address the problem of evil. Not only is God inconceivable, God is also supposedly perfect or “pure.” This is the basis in which theistic proofs are founded upon. For instance, in the first mover argument created by Thomas Aquinas mentioned earlier, it was under the notion that the first mover is “pure actuality.”. Immanuel Kant's argument of morality displays this. The argument is essentially justifying God based on moral reasoning, stating that the sheer existence of objective moral truths indicates a higher, perfect being, as in God. Yet, how is it that an all-good God could allow evil, i.e. war, famine, terminal illness, natural disasters, and species extinction? Furthermore, the existence of these unjustifiable sufferings challenges the idea of objective moral truths at its core. Humans have continuously lived in a state of “evil,” whether that be genocide, starvation, or polycrises, proving the world has never operated in terms of moral order. Therefore, the argument of morality is unsubstantiated. Throughout human history, even more specifically christianity and religious history, every objective moral truth has been challenged. To give an example, the Crusades were a series of wars fought over the span of one hundred years in the name of an all knowing, perfect god. Surely, a being who is perfect would not tolerate such destruction. The problem of evil is a clear-cut opposition to Kant's morality argument, which again, highlights the limitations of theistic proofs.
Thomas Aquinas “Five Ways” uses a deductive argument style, based on observation and logic. For instance, his argument from design outlines the reasoning for purpose within nature, as it is complex and tedious. He then explains that an intelligent designer must be the cause for this (God). An additional “way” crafted by Thomas Aquinas is one that was touched on earlier- the argument from motion (Aquinas 1911-1925). Essentially assuming there must be a first mover, and that must be god. What both of these things have in common is their jump to the conclusion of God being the cause. The premises themselves are valid analytic investigations regarding the beginning of time. Although the questions at hand that sparked these premises and conclusions are inquiries about the universe and not a uniquely Christian uncertainty. In that event, the consistent consensus of god as an explanation is ill-conceived. “The first mover” or “Intelligent designer” could be absolutely anything (Weldon 1958).
Throughout the history of Christian thought, many theistic proofs have been utilized by christian theologians, weaponized, refuted, reworked, and so on. There are limitations to these proofs, which have been emphasized by an over reliance on human reason. Human reason is prone to error, and has proved to be so time and time again. Beyond that, theistic proofs attempt to conceive the alleged inconceivable. As certain theologians attempt to work through this issue, they hit a wall, as the attempt to work through the issue is the paradox at hand. Lastly, theistic proofs have been unable to address the problem of evil. The belief of an all knowing God allowing a world infested with wickedness is an oxymoron, unless of course that god is evil. Theistic proofs do serve the purpose of rationalizing God to those who are heretofore believers, but do not answer to the needs of knowing the unknowable and proving God's existence. Thomas Aquinas’s five ways insufficiently addresses inquiries of the universe, although rational questions, they simply cannot be attributed to “God.”
References
Aquinas, Thomas. 1911-1925. Summa Theologica. New York, New York: Benzinger Brothers.
Aristotle. 1969. Aristotle's Theory of the Syllogism: A Logicophilological Study of Book A of the Prior Analytics. Dordrecht, Netherlands: D. Reidel.
Murphy, John J. 1996. Meister Eckhart and the Via Negativa: Epistemology and Mystical Language. N.p.: Cambridge University Press.
Oxford Dictionary. 2024. 'Prove'. Oxford: Oxford University Press.
Weldon, T. D. 1958. Kant's Critique of Pure Reason. Oxford: Clarendon Press.
*Sofia Scalia is a Student of Philosophy in her first year at the University of St Andrews, Scotland.