Developing an Agile Apologetic


Douglas Groothuis

Article ID:



Nov 15, 2023


Nov 12, 2017

This article first appeared in the Effective Evangelism column of the CHRISTIAN RESEARCH JOURNAL, volume 39, number 02 (2016). The full text of this article in PDF format can be obtained by clicking here. For further information about the CHRISTIAN RESEARCH JOURNAL, click here.


Teaching Christian apologetics at Denver Seminary since 1993 has taught me much. Much of what I write was first sparked or sharpened in the classroom. For years I have advised students to practice intellectual and relational dexterity that deftly marshals apologetic resources in different situations. I call this art agile apologetics. Just as an agile shortstop in baseball can jump, run, and throw from any position, so must an apologist be agile in arguments. As Paul told his mentee, Timothy, “Preach the word; be prepared in season and out of season; correct, rebuke and encourage—with great patience and careful instruction” (2 Tim. 4:2, emphasis added; all Scripture references NIV). Whether our task is easy or hard, complicated or simple, we must be ready (1 Pet. 3:15).

Of course, arguments are always at the forefront of apologetics. Without them, there is no rational Christian witness, and without that, “truth stumbles in the streets” (Isa. 59:14). We must out-think and out-live the world for Christ and His kingdom (Matt. 6:33). But savvy defenders of Christianity must not only master the best arguments; they must also muster them in real time and without canned reactions. Two principles should guide and inspire us to this end.

Worldview Agility. First, apologetic conversations should seek to develop relational and worldview agility. We should know with whom we are interacting and what her worldview is. An accurate diagnosis precedes an apt prescription. Apologetic diagnoses depend on (1) a deep knowledge of the worldviews most commonly held today and (2) the patience and kindness that define active listening. James declares, “My dear brothers and sisters, take note of this: Everyone should be quick to listen, slow to speak and slow to become angry” (James 1:19; cf. Prov. 29:20). A recent article says this: “Active listening is a term experts used to describe the way you listen when you are an engaged presence in the conversation, fully in the moment with the other person, not just sitting there, half paying attention. Think of the different ways you can listen to music. You can put it on in the background while you’re doing something else. Or you can put on your headphones, give it your undivided attention and really notice how it affects you. That is active listening.”1

We need to sharpen our listening skills in a noisy world of distractions.

Sermons and apologetic interactions in Acts always are crafted with different audiences in mind. To the Jews, the message highlights Jesus as the hope of Israel, the Messiah. Few did this more skillfully than Stephen, the first Christian martyr (Acts 7), who invoked the whole history of the Jews to drive this point to the heart. Paul’s preaching to the philosophers at Athens was more philosophical. Since their knowledge of the Hebrew Bible would be slim, Paul quoted their thinkers, showed their errors, and offered the Christian worldview (Acts 17:16–34).

To polytheists, there is yet another approach. After Paul healed a paralytic, those at Lystra wanted to worship him as a god. Displaying a wise apologetic, he replied:

Friends, why are you doing this? We too are only human, like you. We are bringing you good news, telling you to turn from these worthless things to the living God, who made the heavens and the earth and the sea and everything in them. In the past, he let all nations go their own way. Yet he has not left himself without testimony: He has shown kindness by giving you rain from heaven and crops in their seasons; he provides you with plenty of food and fills your hearts with joy. (Acts 14:15–17)

Since Paul was not interacting with Jews, he did not cite Old Testament passages against idolatry (Exod. 20). Instead, he appealed to common sense and general revelation. Paul’s power came from the God who they knew, who gave them “rain from heaven and crops in their seasons” (see Rom. 1:18–23). This is intellectually astute, but less philosophical in tone than what Paul offered at Athens. The apostle was apologetically agile. We should follow him as he followed Christ (1 Cor. 11:1).

Face-to-face conversations are friendlier for dialogue (see 2 John 12). In discussion, we may discover both a person’s worldview and her story. Christian social critic Os Guinness reports that Francis Schaeffer was in a category by himself as a one-on-one apologist. His compassion reached deep inside the questions and objections of the unbeliever. He depended on the Holy Spirit in both his research and in the moments of conversation.2 He thus helped many to follow Christ. Agility in apologetic activity must be empowered by the Holy Spirit, the one whom Jesus called, “the Spirit of truth” (John 14:17; 15:25; 16:13).

I relish the challenge of conversational apologetics. However, I never view a discussion with an unbeliever as merely apologetic. I am speaking to a creature made in God’s image and likeness. Thus, I try to show love and concern for that person as a person, whatever the apologetic possibilities may be. Regardless of the evangelistic result of our endeavors, we should “love our neighbor as ourselves” (Matt. 22:39).

Recently, I spent an hour with a woman who said, “I believe everyone is God.” She also believed that love is the most important thing in the world, and her demeanor and life story backed that up. My approach then became to hint that if everyone is God, then love is impossible, since love always requires a lover, loving, and the loved. Her idea of God was vague and pantheistic. God was not distinct from the cosmos or the self. My goal was to show her the tension in her worldview and to offer an understanding of love based on the God of love.3 Having discussed that (and many other things), I quoted what is perhaps the greatest passage on love: “For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life (John 3:16; cf. Rom. 5:6–8; Phil. 2:5–11).

Because it took time to discern her basic worldview and her attitude toward Christianity, I did not recite this quote early on in our conversation, nor do I always say it in apologetic conversations. Timing is everything, and we should make the most of the limited time we have (Eccl. 3:1–7; Eph. 5:16).

Philosophical Agility. Agile apologetics is animated by a second principle: philosophical agility. Apologetics is multifaceted. There are various families of arguments for God’s existence, such as the ontological, cosmological, design, and moral arguments. Each category of argument holds several versions of that argument. For example, the cosmological argument comes in several conceptual shades: the Leibnizian, the Thomistic, and the kalam.4 The adroit apologist knows each basic form of argument and how to deploy it skillfully. Consider an example.

Sophia is talking to Agnes about her worldview. She did not force the subject, but gracefully introduced it into the discussion. Agnes is pursuing a master’s degree in physics, and she is agnostic. Sophia prods to see if Agnes has any background in philosophy or theology. She finds that Agnes excels in science. That is what sticks to her soul and inspires her. Sophia realizes that the science-heavy kalam cosmological argument is the place to start, since it concerns physics and is relatively straightforward. She presents the argument.

  1. Whatever begins to exist has a cause
  2. The universe began to exist
  3. Therefore, the universe had a cause.

Agnes realizes that the big bang (or the standard model) entails that the universe come into existence out of nothing. She further knows that it is the best established theory to date, since it is based on several lines of converging evidence. Agnes was reluctant to believe the first premise, however, claiming that since subatomic particles come into existence out of nothing, perhaps the whole cosmos could do so. Sophia replied that the two cases were not analogous, since whatever these particles are doing, they are found within a larger context of matter and energy, unlike the idea of the entire universe popping into existence without a cause. Further, she mentioned that it is debatable that these particles exist without causes. To this, Agnes responded that she was not yet convinced, but that she would look into it. Sophia offered to send her several links and book references.

Agnes then asked why this cause must be the God of the Bible. Maybe it was some other God or some impersonal principle. Sophia argued that this cause of the cosmos must be enormously powerful and outside of space and time. She explained that each argument for God need not rationally establish all the attributes of God.5 However, if successful, the kalam argument refutes philosophical materialism and opens the door to the existence of a supernatural being. Sophia could have said more of apologetic significance, but instead let these claims sink in. Agnes replied that she wanted to discuss this argument again. This delighted Sophia, who continued to pray for Agnes and interact with her as a friend.

Some might complain that Sophia failed because she did not explain the gospel to Agnes. Nor did she invite Agnes to church. Others might object that Sophia did not explain how the kalam argument also establishes that the cause of the universe is a personal being.6 But in all things, we must be patient and discerning. Some sow and others reap (John 4:37). Or we may do both. But the outcome belongs to the Lord of the harvest. Come, let us be agile in our sowing and reaping (Matt. 19:37–39).

Douglas Groothuis is professor of philosophy at Denver Seminary, where he directs the apologetics and ethics master’s degree program.



  1. Elizabeth Bernstein, “How ‘Active Listening’ Makes Both Participants in a Conversation Feel Better,” Wall Street Journal, January 12, 2015.
  2. For Francis A. Schaeffer on the Christian life, see True Spirituality (Wheaton, IL: Tyndale, 1971).
  3. On exposing tensions in the non-Christian’s worldview, see Schaeffer’s The God Who Is There (Downers Grove, IL: InterVarsity Press, 1998).
  4. See J. P. Moreland, “The Cosmological Argument,” Scaling the Secular City: A Defense of Christianity (Grand Rapids: Baker, 1987).
  5. Robert Haskins has named it “the whole enchilada fallacy.”
  6. See Moreland, 41–42.


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