Last week I highlighted the fact that the Enlightenment essentially created a Worldview without God, elevating reason over faith. The elevation of reason over faith in the eighteenth century took two general forms. First, pure naturalists relied upon reason as the ultimate authority by which all notions must be judged; in other words, naturalists will not consider rational any notion that allows for the supernatural or otherwise contradicts the foundational assumptions of naturalism. Similarly, empiricists insisted that a notion must have some sort of empirical evidence in order to be considered reasonable. In each of these cases, naturalists or empiricists defined reason on the basis of their foundational assumptions, which assumes reason as its own self-evident authority.
Previously, Christian theologians defined reason differently, not considering it to be the ultimate and independent authority. For Christians, God’s revelation is the supreme authority by which all notions must be judged. This does not mean Christians rejected reason prior to the Enlightenment; rather, Christians acknowledged reason as a God-give tool that allows people, by employing various laws of logic, to judge whether or not a notion corresponds to reality, that is, whether or not it is true.
The definition of faith also hinges upon whether one presupposes naturalist/empiricist principles or the truth and authority of God’s revelation. For example, naturalists might define faith as “believing in spite of evidence to the contrary.” Their definition of reason is constrained by their underlying assumption that immaterial reality is an impossibility. In contrast, faith defined biblically is confident belief in what is “not seen” (Heb 11:1), that is, belief in that for which there is no empirical proof. For example, Abraham believed and obeyed God even though “he did not know where he was going” (Heb 11:8). He believed without empirical proof, but it was perfectly reasonable for him to believe God if reason is defined as a faculty of human cognition that allows a person to judge whether something is true or dependable.
Defining reason and faith in these ways should make determining their relationship simple for Christians. Just as naturalists/empiricists root their understanding of those terms in naturalist/empiricist presuppositions, so Christians understand their relationship based on revelation concerning the reality of God and his creation. Christians understand (reason) by faith (Heb 11:3). God created the universe and everything in it (Gen 1:1–2:1), and this includes both what is material and immaterial (Col 1:16). He rules all things in his universe (Eph 4:6), and “in him all things hold together” (Col 1:17). All things exist and function on the basis of God’s creation and rule of all things (Rom 11:36). These truths alone implicitly ensure the absolute reasonableness of the Christian faith. If reason is that faculty by which a person determines whether a notion corresponds with reality, and if God is the creator and ruler of reality, then all that God has said is self-attestingly reasonable. There may be no apparent empirical evidence for every Christian belief, and a Christian may not understand the reasonableness of every biblical claim, but he can be assured that his faith is indeed reasonable because of the impossibility of the contrary.
In fact, unbelief—whether naturalist or empiricist—is inherently irrational. Because God created all things, and because all people are made in his image, God has already revealed himself to all people; all people know God (Rom 1:19–20). The reasons for God are “plain,” and all people “clearly perceive” this evidence of the existence of God. Reason leads to belief in these things, for the very laws of logic themselves depend for their existence upon the reality of the Christian God. Yet, all people suffer from the noetic effects of sin (Rom 1:21), and thus they suppress this plain knowledge of true reality; all people are born doubting what is self-evident and rational.
Therefore, Christians can assume the reasonableness of their faith as self-evident. For Christians, reason is not the foundation or source of faith, but rather an instrument of faith. This is an important distinction that can give Christians confidence that what they believe is true, but that also ensures that they “honor the Lord as holy” (1 Pet 3:13) in affirming the supreme authority of God’s revelation in their worldview and, consequently, in their entire lives.