Wish I knew.
Some thoughts are found here: http://thegospelcoalition.org/blogs/tgc/2012/03/12/questioning-presuppositionalism/
People who I am inclined to respect on theological issues are inclined (some quite strongly) to think that the answer lies with presuppositionalism – or as one of the links above now describes it, “covenantal apologetics”.
I like a number of the insights which are broadly tied to presuppositional apologetics. I think, for instance, that the modern secular worldview (however one may wish to flesh that out precisely) contains some fairly significant internal tensions – to put it irenically!
However, I find the common concomitant dismissal of evidentialism rather frustrating, because I am convinced that there is good evidence that one ought to trust in Christ. Battering someone with evidence alone is not sufficient for their salvation and battering is of course not often a helpful term, but nonetheless I suspect there is a place for rational discussion of these things which starts on fairly neutral ground. I don’t need someone to be willing to assume (even hypothetically) the truth of Christianity in order to have a fruitful discussion about the truth of Christianity. But I wonder if presuppositionalism amounts to this, in a fundamental way (once one bypasses the window dressing of the specifics of the conversational flow)…
I think there are good reasons to investigate Christianity carefully – and in this investigation, many will choose to follow Christ. There is at least potentially a distinction between the reasons that I offer someone for why they should take the claims of Jesus seriously and the warrant for my own belief that he is the Son of God. Not of course that there is no connection, just that my own belief is guaranteed warrant, if Christianity is indeed true, by the operation of the Holy Spirit. This operation is (as I currently conceive it) a necessary cause for my own belief being justifiably certain – and probably a sufficient one too; but it doesn’t follow from this that the non-believer is in the same situation. K Scott Oliphint defends presuppositionalism by suggesting that on the alternatives, “Wouldn’t we be forced to argue that God probably exists, that Jesus probably rose from the dead, and so our faith is probably not in vain?” But it seems to me that this misses the different epistemic conditions of the believer and the unbeliever.
The Holy Spirit may well make use of evidential argument in convincing people that one ought to trust in Christ; the certainty of God-given faith can perhaps be explained with reference to categories that the presuppositionalist is fond of, while also recognising that the unbeliever too has some grasp of the things of God and this should be encouraged in terms of assessing both the internal consistency of worldviews and the evidence for them which all people are able to grasp. While we will all as fallible human beings interpret evidence imperfectly, we can trust that as there is a God who wants us to know the truth and commands our search for it, careful assessment of the evidence in humility and with reference to God’s revelation will not go to waste for lack of starting with ‘the right worldview’.
This post was originally meant to be a sentence to this effect: there is a difference between any evidential arguments I have for why the gospel is true (and brilliantly, excitingly so!) and the certainty (rather than ‘probability’) of faith – quite why this is so is not entirely clear to me I must admit, but what Alvin Plantinga says about the fact that if Christianity is true it is warranted makes quite a lot of sense. In a similar way to which I can offer small pieces of evidence towards something for which there is overwhelming evidence when the whole scheme of things is taken into account, I can offer small pieces of evidence for the Christian faith, which when ‘everything that is’ is taken into account is much more probably true than any piece of evidence itself suggests; my own attainment of certainty is a product the work of the Holy Spirit in my life, but there is enough evidence for a non-believer to work with and we shouldn’t limit the Holy Spirit in suggesting that we ought not be inclined to give evidence for the truth of the Christian faith or that the only truly ‘biblical’ approach is through assessing presuppositions. The Christian faith provides a good framework for life and thought, indeed the only one that is true and ultimately fulfilling; but I’m pretty sure that there is evidence for it accessible to all as well, both as little pieces and larger thought-systems.
But perhaps I am just a pragmatist at heart?