Faith, Reason, and the Existence of God

Dalton Taylor attends the engineering honors program at Texas A&M University where he studies mechanical engineering 

_MG_0889This past year (2018-2019), I participated in a philosophy class which developed my ability to articulate and critically assess positions on ideas. One of the branches of philosophy we studied was the Philosophy of Religion. And one of the main topics we investigated was the merits of using faith and rationality as it pertains to one’s belief in the existence of God.

Saint Thomas Aquinas

One of the first philosophers and theologians to present a “proof” for the existence of God was St. Tomas Aquinas (1225-1274). His arguments are separated into what philosophers refer to as The Five Ways. His second argument is one of the more explicit and compelling “proofs” which demonstrate his attempt to combine a rational approach to a claim originally based in faith. :

  1. We perceive that things in the world have causes
  2. Nothing can exist before itself
  3. Therefore, nothing in the natural world is an efficient cause for itself
  4. If there is not an efficient cause then the effect does not exist
  5. Therefore if the first thing in a series does not exist, then neither does the series
  6. If time had no beginning then there would be no first event and therefore, the series of the universe would not exist
  7. This is obviously false because reality exists
  8. Therefore time has a beginning
  9. Therefore, it is necessary to admit a first efficient cause, we call this God

Greek Rationalism

This argument is an attempt by Aquinas to provide a rational explanation for the existence of God. The 1200s were a time in Europe when the educated rediscovered the concepts formulated during Ancient Greece, like the ideas of Plato and Aristotle, which led to the introduction of Greek rationalism into the intellectual mainstream.

Greek rationalism is the view that there are objective truths within the universe and we as humans are able to conceptualize them through using our faculties of reason. As a result, there was a movement within the religious community to create ways to “prove” the existence of God by way of reason. Aquinas along with many other famous theologians saw this as an opportunity to use the rediscovery of rationalism to create non-faith based arguments in order to secure/convince others in the belief in God. 

Matter and Spirit

Faith and rationality are both valid avenues to come to conclusions of truth. This is evident because a claim like “God exists” can be proved both from faith and reason. Human beings seem to have two conflicting instinctual assumptions about the world.

The first thought process is that what we perceive is reality. This assumption is also fundamental to the scientific method and is based on physical or logical evidence. In order to validate the scientific method, we must work from the assumption that humanity has the capacity to reason in order to model the natural world in our mind.

The second process is that there are aspects of experience which transcends the natural world and therefore has no physical evidence or rational explanation, also known as faith. An example of this is personal experience.

Many philosophers refer to non-conveyable characteristics as qualia. An example of certain qualia is the experience of color. For example, consider how one would convey what the color red is to a blind person. The sharing of ideas helps explain why humans are such social creatures. If one believes that there is nothing more to the natural world, then the logical conclusion is a world based in substance physicalism, which eventually leads to existentialism and nihilism. In both schools of thought there is no point to life or society; we humans are just collections of cells reacting to stimuli. 

Despite the difference in bases for the processes,  human beings use faith and rationality to explain experience. Both methods are important for determining truth in the world. Rationality is the basis of science and the main method of the expansion of knowledge. Meanwhile, personal experiences, which cannot be rationalized, are evidence of something other than the material world. This leads to the use of faith for certainty in aspects beyond our rationality like consciousness and emotions.

Faith-Based Claims

Faith is one of the tenants of almost all religions across the world. Faith-based claims can be just as true as rational claims. Not all claims without rational evidence are true, however.

True statements based on faith feel true. This is because concepts like consciousness have no rational necessity for being true. It could be just as false but most people know that consciousness exists because of the faith they have in their own personal experiences.

Another example of this is the statement that God exists. For a long time, this was a contention purely based on faith without reason. After many theologians from the medieval period were exposed to the writings of the Ancient Greek thinkers, there became a new period where scholars were using the rationality to articulate the reason for their faith, thus marrying the two schools of thought.

Overall, the attempt by theologians like St. Thomas Aquinas to balance the two thought processes of rationality and faith gives an insight into the human psyche. Although there are concrete and rational answers to many questions of the universe, some principles require faith rather than reason to assess what we know.

Compliment this article with Gustav Mahler’s expression of his religious questions through his compositions in the essay Can Music Be Philosophical? 


Gracyk, Theodore. “Argument Analysis of the Five Ways.” Aquinas: Five Ways to Prove That God Exists — The Arguments, 


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