Can we trust reason if God doesn’t exist?

Photo: Getty Images/DiatoZen
Photo: Getty Images/DiatoZen

I respond to the assertion that if the Christian god does not exist we cannot trust our own reasoning.

C.S. Lewis and other Christian apologists often formulate arguments such that an atheist has no grounds to trust their own reasoning faculties if it is the case that the universe were not designed by the Christian god. C.S. Lewis, in his book The Case for Christianity, explains,

“Supposing there was no intelligence behind the universe, no creative mind. In that case, nobody designed my brain for the purpose of thinking. It is merely that when the atoms inside my skull happen, for physical or chemical reasons, to arrange themselves in a certain way, that gives me, as a by-product, the sensation I call thought. But is so, how can I trust my own thinking to be true? […] But if I can’t trust my own thinking, of course I can’t trust the arguments leading to Atheism, and therefore have no reason to be an Atheist or anything else. Unless I believe in God, I cannot believe in thought: so I can never use thought to disbelieve in God” (Lewis, 32).

Lewis’ reasoning has several flaws. First, Lewis assumes that we cannot believe our reasoning faculties are reliable/trustworthy if it is the case that random processes (rather than a supreme intelligence) lead to thought. Why is this the case? Lewis merely, at least in this passage, only asserts that random processes do not provide justification for believing our thought faculties are available – that thought processes can only be thought of as reliable if a supreme intelligence had created them.

The process by which thought came to exist, I think, has no bearing on whether thought processes can be thought of as reliable, but rather looking at perhaps the results and analyzing the accuracy (in most cases) of said thought processes should lead to whether we can be justified in believing our thought processes are reliable.

As I explained in a piece refuting presuppositional apologetics, believing induction — that the future will resemble the past given sufficient trials or experiences — is reliable…and the circularity of induction is not only a problem for atheists, but also a problem for theists which — in order to start reasoning at all — ought to be believed lest we live reckless, destructive lives.

We can distrust out own thinking when we have good reasons to, but in tasks of everyday life we have very good reason to trust our thinking. We believe that our toothbrushes are not going to randomly fly out of our hands or harm us in some way. We understand that when we pour water from a pitcher water will empty into a glass and not spill. Because of tremendous experience with mundane life tasks (and even more complex tasks) we have good grounds to trust our reasoning; our thought processes are constantly vindicated when we are able to properly function as human beings. God, then, need not enter into explanations about justification for reasoning.phillyflight

Another flaw in Lewis’ piece surrounds ‘arguments for atheism’ – as if disbelief in Christian theology is only justified if atheists can raise successful counter-arguments. While several good counter-arguments exist to cast significant doubt upon Christian belief (problem of natural suffering; incompatibility between free will and divine foreknowledge; similar epistemological methods leading to different conclusions about religious beliefs…) , it is ultimately the case that without Christians advancing good arguments for Christian belief there is no good reason to suggest Christian belief is true [the burden of proof is on the Christian who makes a positive claim].

Third, why does Lewis privilege the Christian god over competing religious claims; that is, why assume that the creator of the universe is the Christian god? Lewis’ argumentation, if we accept it for sake of argument, can only lead someone to believe a creative intelligence which created the universe exists or existed. After all, the Christian god is not the only possible ‘greatest conceivable being.’

Finally, Lewis’ argument just reeks of ‘God of the gaps’ or ‘mystery therefore magic‘ reasoning. Because the atheist can’t give an accounting for thought processes without assuming the Christian god exists, Lewis asserts, the Christian god must exist. Centuries ago (and even in decades past) theists almost certainly have used this line of reasoning with other natural phenomena such as earthquakes, diseases, lightning, etc.; because there appeared to be no explanation for x phenomenon God must exist – only an explanation appealing to God is viable since no good competing explanations exist.

Even if the atheist has no accounting for reasoning (or any other phenomena), the theist is not justified in asserting that because something can’t be explained one has good reason to suggest the Christian god exists. The atheist can say ‘I don’t know.’ How ought one bridge the gap from ‘I don’t know’ to the Christian god did it…and the story of the resurrection, Holy Trinity, various miracles, a global flood, etc. are also true by the way.

A more modern version of Lewis’ argument is recast by Christian philosopher Alvin Plantinga. Watch Plantinga discuss his evolutionary argument against naturalism with atheist philosopher Stephen Law below.

As always, feel free to comment below.


Justin Vacula

Justin Vacula hosts the Stoic Philosophy Podcast; serves as co-organizer and spokesperson for the Northeastern Pennsylvania (NEPA) Freethought Society; and has hosted monthly Stoic Philosophy discussion groups for the Humanist Association of Greater Philadelphia. He has appeared on and hosted various radio shows and podcasts; participated in formal debates and discussions; was a guest speaker for college-level courses; was featured in local, national, and international news; and has been invited to speak at various national, local, and statewide events. Vacula received bachelor's degrees in Philosophy and Psychology, a minor in Professional Writing, and the distinguished W.A. Kilburn Memorial Award for Philosophy from King's College in Wilkes-Barre, Pennsylvania. He is currently living in the Scranton, PA area attending Marywood University's graduate-level Mental Health Counseling program and has worked with the Arc of Luzerne County's Transition to Community Employment program as a teacher's assistant and job coach alongside adult learners with intellectual and developmental disabilities. He also plays poker; volunteers as a member of the website and media team for the Greyhawk Reborn Dungeons & Dragons campaign while playing at events in the Eastern United States; and enjoys metal music.