Dr. Keller defines defeater beliefs as a culture’s “common sense consensus beliefs that automatically make Christianity seem implausible to people.” Because these deeply-entrenched beliefs are assumed to be true, people hastily dismiss the Christian faith since it contradicts them.
If, for example, a culture is convinced that all religions are true, Christianity’s exclusive claims are quickly rejected as ludicrous. Implausibility structures are culturally relative, meaning that “Christianity is disbelieved in one culture for totally opposite reasons it is disbelieved in another.” This is an important point highlighting the sociological dimension of fallen humanity’s suppression of the truth. While it’s accurate to say that depravity is ultimately and universally responsible for unbelief, the “course of this world” that the unregenerate follow is not monolithic but varies across historical period, geography, people group, etc.
Recognizing the inevitable presence of implausibility structures and how they stand as barriers to the gospel has important implications for how we seek to commend the faith to postmodern hearers. Some Christians insist that we abandon argumentation as a means of gospel persuasion and, instead, rely on the apologetic power of Christian community and ministries of mercy to those outside the church. Keller’s reaction to this line of thought is worthy of quoting at length:
"I couldn’t agree more that post-modern people come to Christ through process, through relationships, through mini-decisions, through ‘trying Christianity on.’ They are pragmatic rather than abstract in their reasoning, etc. But the books that are against any arguments at all seem to miss the fact that the extreme pragmatism of non-Christians today is part of a non-Christian world-view. Our post-enlightenment culture believes what has been called expressive individualism. That is – ‘it is true if works for me.’ This obviously is based on the view that truth and right-or-wrong is something I discover within my own self and consciousness.Keller goes on to explain that sharing the gospel involves a two part approach, a negative apologetic dimension that consists of deconstructing the reigning cultural implausibility structure, and a positive aspect of sharing the gospel. This communication must be done in a fashion so as to connect the gospel message to what he calls the culture's base-line narratives. He writes, "In short, you have to show in line with the culture's own (best) aspirations, hopes, and convictions that its own cultural story won't be resolved or have a 'happy ending' outside of Christ."
What then of the claim that ‘post-modern people don’t want arguments – they just want to see if it works for them’? All right – as with any form of contextualization, let us as evangelists enter – adapt partially – to the culture of expressive individualism. Let us show them the reality of changed lives. Let us use narratives rather than long strings of logic. But at some point you must also challenge the sovereignty of individual consciousness. Jesus is Lord, not my personal consciousness. At some point, the idea that 'it is true if and only if it works for me' must be challenged. We have to say: 'Ultimately that is correct - in the very, very long run, obeying the truth will 'work' and bring you to glory and disobeying the truth will 'not work' and bring you to ruin. But in the short run (like - even throughout all the rest of your life!) obeying the truth might lead to ostracism, persecution, or other suffering.'"
Keller advocates presenting the gospel using a three-layered approach composed of these two aspects. The layers are as follows:
a) Brief gospel summary. First, the gospel must be presented briefly but so vividly and attractively (and so hooked in to the culture's base-line cultural narratives) that the listener is virtually compelled to say 'It would be wonderful if that were true, but it can't be!' Until he or she comes to that position, you can't work on the implausibility structure! The listener must have motivation to hear you out. That is what defeaters do - they make people super-impatient with any case for Christianity. Unless they find a presentation of Christ surprisingly attractive and compelling (and stereo-type breaking) their eyes will simply glaze over when you try to talk to them.Keller illustrates how this approach looks interacting with two pervasive Western cultural concerns : 1) personal freedom and identity and 2) unity and diversity. He then gives brief but helpful examples of deconstructing six dominant defeaters in Western civilization: 1) Christian exclusivism in light of religious pluralism, 2) evil and suffering, 3) the ethical restrictiveness of Christianity, 4) the record of Christians, 5) the angry God, and 6) the unreliable Bible.
b) Dismantle plausibility structure. ....The leading defeaters must be dealt with clearly and quickly but convincingly. Defeaters are dealt with when the person feels you have presented the objection to Christianity in a clearer and stronger way than they could have done it.
c) Longer explanation of the person and work of Christ. Now, if people find you have at least undermined the defeaters in a listener's mind, you can now return to talking at greater length about creation, fall, redemption, and restoration. If you try to do apologetics before you pull off a quick, attractive presentation of Christ, people's eyes will glaze over and they will become bored. But if you try to do a very lengthy explanation of the meaning of Christ's cross and resurrection before you convincingly deal with the defeaters, they won't listen to you either.
The article concludes with points the unbeliever who's ready to explore the Christian faith must consider, including this one about doubt: "Your doubts are really beliefs, and you can't avoid betting your life and destiny on some kind of belief in God and the universe. Non-commitment is impossible. Faith-acts are inevitable." What Keller is stressing here is that there is no such thing as ideological neutrality. Objections to the Christian faith don't spring from nowhere but are expressions of alternative systems of belief which are themselves in need of a defense.
Part of our evangelistic task, then, is to help our hearers become more aware of their own presuppositions. We must ask them the same question Cornelius Van Til did in his "Why I Believe in God": "Will you not go into the basement of your own experience to see what has been gathering there while you were busy here and there with the surface inspection of life? You may be greatly surprised at what you find there." Then, if we are prepared, we can take their hand and lead them downstairs.