Seminary Viewpoints

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The Key to Effectually Communicating with Unbelievers

Renton Rathbun | April 14, 2022
Theology Thursday

Adapted from Renton Rathbun’s Spring 2022 JBTW article and discussed on The Steve Noble Show on April 14

Typically, when believers defend their faith — or God’s general revelation confronts unbelievers in their own experiences — believers turn to natural theology. Natural theology is a field of study that seeks to understand God and his attributes through creation, specifically through reasoning and observing nature rather than by referring to special revelation. The concept stems from Romans 1:19-20:

“For what can be known about God is plain to them, because God has shown it to them. For his invisible attributes, namely, his eternal power and divine nature, have been clearly perceived, ever since the creation of the world, in the things that have been made. So they are without excuse.”

That passage demonstrates the indisputable fact that God implants in every man knowledge of His existence and His nature through His creation. But is this natural knowledge enough common knowledge with believers for them to engage in theistic debate? By answering this question from a Reformed perspective, scholars both within and outside of Reformed scholarship can find the key to effectually communicating with unbelievers.

Does Mere Assent Count as Common Knowledge?

At the outset of any discussion, two opponents agree on terms and word usage to ensure that they actually communicate. Some wonder if this assent provides enough common ground for believers debating with unbelievers. However, assent is not knowledge.

Unbelievers’ mere assent to natural truths does not replace true agreement because unbelievers still have radically different explanations for those truths. For example, Stephen Hawking and a Christian physicist might have agreed that light acts like a particle and a wave and travels at 186,282 miles per second. Although their descriptions might “agree,” their explanation of how those things are possible would be vastly different. They could only have an appearance of common ground.

Some then may ask, “Well, why can someone still not debate if descriptions of natural truths are exactly the same?” But describing them the same way while explaining them differently does not suffice. As Dutch Reformed apologist Cornelius Van Til (1895-1987) maintained, “Every description is an explanation of a fact — the description of a fact is not a neutral category that exists irrespective of God.”1 Descriptions, as interpretations, rely on their presupposed explanations to make any sense.

Moreover, based on the logical reasonings of philosophers Hume and Kuhn, Van Til was right to insist that description and explanation rely on each other for meaning and coherence. Even the philosophical and scientific communities understand that description is the exercise of interpretation, and that interpretation makes no sense without its relation to the conditions that make interpretation possible.2

In summary, this sense of common knowledge is not sufficient for debate, according to the Reformed theologian. Unbelievers don’t really know like believers do and can’t communicate effectually since they lack common ground.

Address Suppressed Knowledge When Communicating with Unbelievers

It seems like we’ve reached a dead end with no hope of effective formal debate with unbelievers. But read on in Romans 1.

Right after Paul states that unbelievers are without excuse (Rom. 1:19-20), he explains they choose to suppress God in order to serve the creature rather than the Creator (1:21-25). They want to interpret the world with themselves as the final reference point, not God. Consequently, they create a complex explanation of facts to bolster their autonomy. This rebellion prevents them from having common knowledge with believers even though they have knowledge of God.

Therefore, instead of trying to find common knowledge, believers can effectually communicate with unbelievers by making them realize that they are suppressing the truth. This method makes unbelievers aware that God is the final reference point. Believers can accomplish this in three steps:

  1. Demolish barriers. In their suppression of the truth, unbelievers use anti-Christian arguments as “comforters.” 2 Corinthians 10:3-6 tells us to demolish all arguments raised up against the knowledge of God.
  2. Demonstrate the impossibility of unbelief. Sin relies on incoherence for its existence. Proverbs 26:4, 5 tells us how we ought to engage in demonstrating the impossibility of the unbeliever’s own system. When followed consistently, it leads to absurdity.
  3. Deliver the Gospel. Steps 1 and 2 allow for the unbeliever to recognize his own suppression. But whether formal or informal, the discussion doesn’t stop with proving unbelievers wrong. Ultimately, God calls believers to lead them to salvation through the power of the Holy Spirit by giving them the Gospel.

Be prepared to prove the truth no matter what topic comes up when communicating with unbelievers. But remember, apologetics is a tool for irreproachably approaching Gospel conversations — because only Christ, not knowledge, saves.


1William D. Dennison, In Defense of the Eschaton, ed. James Douglas Baird (Eugene, OR: Wipf & Stock, 2015), 46.

2Cornelius Van Til, Common Grace and the Gospel (Phillipsburg, NJ: Presbyterian and Reformed, 1977), 5.