The Relationship between Faith and Reason

Can you see “trust?” The trust you have in a spouse? No, but you know it exists.

                Mark Twain once said, “Faith is believing what you know ain’t so.” I hold to the controversial opinion that Samuel Clemens (Mark Twain) isn’t that great of an author, but I think even less of his understanding of faith, and his philosophical views in general.  How do we respond to someone when they say something like this? Twain’s definition of faith has now permeated our culture, and we see it even leak its way into the church.

              First, I should begin by defining biblical faith. Faith, the Greek word pistis, would later be translated as “fides,” the Latin for “trust.” Historically, it has been interpreted as closer to “trust” than the latter-day associations we have with the word. The Greek word is even derived from pi-tho: “to convince by argument.” It would be wrong to argue purely from the way the word was derived, as word meanings do change over time, but it can help us. More importantly, we can argue from how the word was used by the authors of the Bible. 

              Hebrews 11:1 in the King James famously records, “Now faith is the substance of things hoped for, the evidence of things not seen.” Many over-emphasize the “unseen” part of the verse and come to an erroneous conclusion. Note the word “evidence.” While we can’t see the wind, we can see ”evidence” of the wind from its effect; it can also be measured and understood. This verse must also be interpreted in light of the numerous texts that demonstrate that Paul and others used persuasion and reasoning, as well as  the command to worship God with our mind (Mark 12:3). The fact that faith is not visible does not mean that it is contrary to reason.

              Can you see “trust?”  The trust you have in a spouse? No, but you know it exists. David knew he could trust God to aid him in slaying the giant Goliath, because God had been there for the lion and the bear. When confronted by the disciples of John the Baptist, Jesus pointed them to the evidence of fulfilled prophecy as a reason for their teacher to trust that He was the Messiah. It was not a call to believe blindly. It was not a call to believe without or against what was known or could be demonstrated.

              What of John 20:29 that records, “Blessed are they who did not see, and yet believed?” Does this elevate blind faith? The context of this was Thomas’ extreme doubt, where he was not believing the evidence of Jesus Himself before his eyes and kept needing to see more and more. The section closes with, “So then, many other signs Jesus also performed in the presence of the disciples, which are not written in this book; but these have been written so that you may believe that Jesus is the Christ, the Son of God; and that by believing you may have life in His name” (John 20:30-31). John was presenting his entire account as evidence to believe in Jesus; if he were doing that, then it would be contradictory for him to suggest that less evidence is better. Jesus was addressing hyper-skepticism, not normal doubts or questions, and not the desire to examine evidence, but the denial of evidence when it’s in your face. That’s a very different issue.

              Faith is not a momentary thing, either. John 15:4 exhorts the Christian to “abide” or actively continue in Christ. Our doubts may come and go, but faith is like a relationship with a spouse. There are moments when we are more sure or perhaps happier with our spouse than others, but we have an active commitment we have made with them, and that commitment — that trust, itself — continues apart from measuring its strength.

              A biblical definition of “faith” is an active (or abiding) trust based on evidence. Faith isn’t based on what we do not know, but on what we do know, including about God, and He calls us to learn more and have our faith grown as we build a relationship with Him. Some have attempted to follow another worldview that puts faith at odds with reason and more in line with Twain than Jesus.

              While you likely haven’t heard the term “Fideism,” its influence is surprisingly wide. Author Douglas Groothuis defines “Fideism” as, “an attempt to protect Christian faith against the assaults of reason by means of intellectual insulation and isolation.” It’s even called “an antidote to apologetics.” My desire is to meet the growing intellectual challenges, and that desire is based on the scriptural call to engage in what we call “apologetics” (1 Peter 3:15) — that is, giving a defense, using evidence in logical argumentation for why we believe what we do. Others have downplayed this as a failed experiment by Paul or even only something to be done inside the church, not as a part of evangelism.

              Fideists sometimes claim that you can’t “argue someone into the kingdom” because of the fallen nature of man. Groothius notes that, “Certainly, the effects of the Fall make apologetics more difficult, but they need not render it impossible.”  I routinely interact with and read writings of people who indeed were “argued” into the kingdom like C.S. Lewis, Lee Strobel and J. Warner Wallace, among others. These are famous names who were convinced of the truth of Christianity after engaging with well-learned individuals who were able to respond to their doubts and questions.

              Fideists on the other hand, would argue that apologetics is inappropriate and fruitless. God will either save someone or not, and they will either believe (have faith) or not, regardless of any evidence given, ignoring that the Holy Spirit can and does use this evidence and ignoring the patterns of evangelism we see in the New Testament, especially Acts.

              But most people aren’t Fideists, so how does this bad idea worm its way in? It’s easier to tell people to “have faith” than to answer hard questions about what we believe and why we believe it. It even sounds more “holy” to say things like “I just believe,” but as someone else has said, “Stupid for Jesus, is still stupid.” Fideism treats reason as an enemy, and that’s led to many leaving the church.

              Right now, multiple research studies like those at Barna and various ones given to Ratio Christi during my time there, indicate that 70-80% of Christian young people leave the faith when they hit the college campus. Time and time again, when asked why, it’s the lack of depth, lack of answers, and the idea that Christianity is opposed to science (and behind that assumption, they usually imply “against reason”).   If we don’t give young people a robust defense of Christianity or use it when reaching out to others, they will accept the strong critiques and attacks on Christianity as true, and we will seem like a people with no reason to think or believe the way we do, and they will both reject Christianity and think Christians are irrational furthering the divide in our culture.

              Reason should be used to help us understand both the innerworkings of our faith and also to know the true faith and demonstrate truth to others. It’s our ally, not our enemy. The idea that faith and reason are opposed is more in line with the gnostics. Gnostics were a famous group against whom our forefathers wrote an eloquent defense of the truth to combat their twisting of scripture. Let’s continue the tradition of following the biblical command to worship God with our minds.


Groothuis, Douglas. Christian Apologetics A Comprehensive Case for Biblical Faith. IVP Academic  Downers Grove, Illinois. 2011.