Can we know that God exists through natural reason? Sadly too many refuse to engage in a true dialogue over this question. Some claim that faith alone is needed to affirm that God exists. Others do not understand what reason is – looking only for scientific evidence. Yet, this question is the foundation for any true exploration of belief in a deity. If it is possible for humans to use natural reason to prove that God exists, then the question of religion in today’s society remains imminently relevant. With a true understanding of natural reason, one logically concludes that God exists.
Richard Dawkins’ famous book the God Delusion believes the question of God’s existence relies on scientific evidence and cannot be proven. He writes, “Either he exists or he doesn’t. It is a scientific question; one day we may know the answer, and meanwhile we can say something pretty strong about the probability.” Dawkin’s argument is faulty for a number of reasons, one of which is that if God is immaterial how can his existence be reduced to a matter of empirical science alone? Dawkins casually dismisses Aquinas’ five proofs for the existence of God, ridiculing what he deems to be the simplicity of the arguments. Yet, Dawkins himself does not engage his human reason – primarily he makes use of what he considers to be counter examples based on science, not on reason.
Aquinas’s proofs for the existence of God are indeed (as Dawkins claimed) simple. They are simple, but also difficult to refute reasonably. Aquinas writes that everything that moves (changes) must have a caused by a mover. This is not only true in the scientific world (though this is how we know it to be reasonable) it is true in the world of ideas as well. This is a distinction that Dawkins does not engage – he looks only at the material universe. For example, natural reason allows us to conclude that 1 plus 1 is 2 without actually seeing one apple and another apple equally two apples. Aquinas engages proofs that using logic and reason (for the world itself is structured and reasonable) human beings are capable of knowing we can ascertain the existence of God. Sadly, it seems that those who either emphasize science to the exclusion of reason or deny the existence of truth or reality itself, which obscures the affirmation of reason.
The First Vatican Council insists that not only are faith and reason compatible, they actually support one another. Part of the difficulty for those who reject that God can be known by natural reason, is that who God is in Himself is transcendent and other in a way that we can not ever completely understand. Vatican I says that he is “completely simple and unchangeable spiritual substance” – His nature makes God different from any created thing. Faith is a gift from God which allows us to know Him in Himself. However, knowing who God is is different than knowing that He exists. We are able to know that He exists from the structure of the created world, not merely looking at scientific evidence, but using our natural capacity for reason to look at the scientific world and what it points to – a first mover, a supreme being, a first cause.
It certainly is possible to know through reason that God exists, but still not believe in Him. A reasonable person, however, is a theist.