Jonathan Prejean has said that a Protestant cannot establish the inerrancy of Scripture on an evidentiary basis alone.
Although his contention has immediate reference to the limits of the historical method, yet his objection is presumably broader than that; for were he to believe that a Protestant could establish the Protestant rule of faith, or elements thereof (e.g., inerrancy, sufficiency, perspicuity), consistent with Protestant criteria, Prejean would be Protestant rather than Catholic. At the very least, he’d be far less critical of the Protestant alternative.
So what, exactly, is the evangelical case for inerrancy? I don’t plan to offer a full-dress argument here, but just to present the steps of a multi-stage argument so that we have a clearer idea of what is being affirmed or denied.
In this brief essay I don’t presume speak as a representative of any particular position. Just as there are different versions of fundamental theology in Roman Catholicism, Evangelicals differ on issues of apologetic methodology.
i) The inerrancy of Scripture is implicit in the inspiration of Scripture. Given the divine identity of Scripture as God’s word, inerrancy is a necessary entailment thereof.
If God has spoken in Scripture—more precisely, if Scripture is God speaking, as the vehicle of divine self-revelation--then Scripture is inerrant.
ii) This follows from the nature and purpose of God in revealing his will to man. It assumes that God is truthful, that God’s purpose in revelation is to reveal the truth, that God is able to reveal the truth through the medium of human agents and human language.
iii) So, at this stage, an evangelical apologist would need to establish the self-witness of Scripture, as well as anterior assumptions regarding the nature of God and the purpose of revelation.
Among some of the treatments that cover the relevant bases, we have:
Frame, J. “Scripture Speaks For Itself,” in J. Montgomery, ed., God's Inerrant Word (Bethany Fellowship, 1974), 178-200.
_____The Doctrine of God (P&R 2002).
Turretin, F. Institutes of Elenctic Theology, Volume One (P&R 1992).
Warfield, B. Revelation & Inspiration, Works, Volume One (Baker 2003).
iv) None of this calls for any corroborative evidence, unless you believe that the existence of God must be established at this stage of the argument.
But while the existence of God is a metaphysical presupposition of the above, it is not an epistemic assumption, per se, for it is possible to argue either way: to argue from God to Scripture, or to argue from Scripture to God.
People have been converted to the faith just by reading the Bible alone, or by trying to prove the Bible, or even by trying to disprove the Bible. Which brings us to:
i) The next step is why we should believe any of this. And to that question there is no uniform answer, for different men are impressed by different types or lines of evidence. Here is one classic answer:
We may be moved and induced by the testimony of the church to an high and reverent esteem of the holy Scripture. And the heavenliness of the matter, the efficacy of the doctrine, the majesty of the style, the consent of all the parts, the scope of the only (which is, to give all glory to God), the full discovery it makes of the only way of man’s salvation, the many other incomparable excellencies, and the entire perfection thereof, are arguments whereby it doeth abundantly evidence itself to be the Word of God: yet notwithstanding, our full persuasion and assurance of the infallible truth and divine authority thereof, is from the inward work of the Hoy Spirit bearing witness by and with the Word in our hearts.
WCF 1:5. Cf. Calvin, Institutes 1.7.5.
ii) Notice that what we have here is a combination of internal and existential evidence. None of it depends on corroborative evidence.
And for many people, one or more of these reasons is reason enough. We could also add to this list.
3.A two-step option
i) Another popular defense is a two-step argument. The apologist will argue that there is sufficient historical evidence to establish the historical Christ, as described in Scripture. And this includes the NT witness to the divinity of Christ.
ii) Oftentimes, this phase of the argument will appeal to corroborative evidence, viz., archeology. I’m not sure if corroborative evidence is actually necessary to make this case. But that’s how it’s generally done.
iii) The next step will be to argue that, given the divinity of Christ, you can then upgrade the probable argument to a certain argument, for a divine Christ is in a perfect position to authorize the OT and preauthorize the NT.
4.What’s the alternative?
i) Let us keep in mind that the same question can be posed of Roman Catholicism. If a Catholic authorizes the Bible by appeal to the church, that only relocates the question, for the question then will be, “Why believe the Church?” “Why believe that your church is the true church?”
ii) This, in turn, becomes a question of what historical evidence will probilify the claims of Romanism or Orthodoxy or whatever.
iii) Since, moreover, Catholicism appeals to, and applies to itself, descriptions of the true church in Scripture, it is, to that degree, contingent on the prior veracity of Scripture, and not the other way round.
The Roman Church can only be the true church if it is true to the definition of the true church in Scripture, which presupposes the truth, not of Romanism, but of Scripture.
So Romanism must employ the Protestant rule of faith as a ladder to get reach Romanism in the first place.
5.Inerrancy & evidence
i) Corroborative evidence is used, not so much to establish the inerrancy of Scripture—except, indirectly, in the case of #2—as it is to defend the inerrancy of Scripture against historical objections.
ii) Such a defense is probabilistic in character, but then, the objections are probabilistic in character, so it’s answering the critic on his own level. There is no clear reason why a Christian apologist should be held to a higher standard than the critic. We don’t apply that double-standard to other fields of inquiry.