Christian apologetics is the discipline of giving reasons to believe the Christian message and reasons to reject intellectual attacks on Christianity. Its purpose is to help individuals by defeating intellectual objections so they can hear and accept the Christian message.
Apologetics is a thriving business among Protestants; not as much among the Catholics and Orthodox. Presuppositional apologetics, which is controversial even among Protestants and is largely associated with Calvinism, is based on two insights.
The first is that false presuppositions about the basic nature of reality will block an individual’s ability to accept the Christian message. All the correct evidence and reasoning in the world will do him no good until he corrects his false presuppositions.
This is ultimately not a rational process. Calvinism places a special emphasis on the Bible passages teaching that mankind in its natural state cannot help but reject God until God gives the individual spiritual life which is the ability to accept the Christian message. See, e.g., John 6:44 and Ephesians 2:1—10. But God also works through means, and one means of coming to faith is to hear and accept true evidence.
Many Christians reject presuppositionalism because in their experience it looks like circular reasoning: “You cannot prove God, you can only presuppose Him.” Some Christians may talk this way, but you can prove God. You just have to know the correct way. Ultimate truths are not known using ordinary ways of reasoning. See here for more details.
In any case, it’s clear that everyone has presuppositions, that most people are only dimly aware of exactly what they are, and that false presuppositions cause false beliefs, especially false beliefs about the most fundamental facts of reality.
The second basis of presuppositional apologetics is the recognition that mankind has no right to reason in a way that is autonomous from God. There is a truth about God and you have no right to reject it, even if your reasons seem good to you. If you reject a valid proof of God, a presuppositional apologist will not say “OK, let me try a different proof…” He will say “Your thinking is faulty because your presuppositions are false; here’s why…”
Religious discourse between a Christian and a non-Christian is never discussion between neutral parties. Neutrality in one’s stance toward God is impossible. Those who think they are neutrally considering the evidence are unaware of their presuppositions and their commitment to human autonomy. They have taken a side but they have not acknowledged to themselves the nature of this commitment.
These two ideas, that false presuppositions must directly be dealt with and that mankind does not have the right to think any way they want about God seem obvious and important to me, but many serious Christians reject presuppositionalism. Therefore, I propose a thought experiment:
Imagine an individual who considers himself a serious student of mathematics (SSM). His professor is teaching, let’s say, the Fundamental Theorem of Calculus. A rather important theorem. Of Fundamental Importance to Calculus. But SSM rejects it. Maybe he rejects the theorem without studying the proofs offered by the professor and the textbooks. Maybe he studies the proofs but declares them invalid for reasons of his own invention. The professor attempts to reason with him but to no avail. Mr. SSM rejects the theorem and creates his own calculus.
Is SSM justified in his rejection? Obviously not. A neophyte has no right to reject what scholars have learned over hundreds or thousands of years. The Fundamental Theorem of Calculus is the result of thousands of years of mankind’s greatest minds studying mathematics. Since mathematics is real their discoveries are real, and therefore to reject an established truth of mathematics is to be willfully ignorant. You have no right.
[I use “right” in its primitive sense, not its debased modern sense. “You have no right” means “you have no justification.”]
You have no right to reject something true. You have no right to reject the proofs until, at minimum, you understand the subject, what the theorem under discussion says, and the structure and logic of the proofs. And if the theorem is true your reasons for rejecting it don’t matter. You’re wrong.
If the student persists in his rejection of mathematics he should not be treated respectfully by mathematicians. He’s not holding a valid alternative belief. He’s refusing to think correctly. If he persists in conversing with them, mathematicians would be derelict in their duty to the truth if they failed to correct his errors. His false beliefs are ultimately caused by false mathematical presuppositions which must must be identified and corrected. He does not have a right to his own version of mathematics.
If the analogy is not obvious, let’s spell it out. SSM represents a non-Christian. The Fundamental Theorem of Calculus is any truth about Christianity, especially that God exists. The proofs of the Theorem are the evidences for the Christian doctrines. The professor is anyone who presents Christian evidence. SSM’s rejection of the Theorem and its proofs is the typical response of an unbeliever when confronted with Christian doctrine or the evidence which supports it. He’s in the wrong and should be treated as such.
And if it is valid to correct a wayward student’s false mathematical presuppositions and demand that he place himself under the authority of the mathematical truths that mankind has discovered rather than making up his own mathematics, it is even more valid to take a presuppositional approach to conversing with recalcitrant non-Christians.
There are some apparently-valid objections to the analogy. Yes, SSM has made a commitment to mathematics whereas the typical apologist’s interlocutor has no commitment to Christianity. [But he does have a probably-unconscious commitment to his faulty worldview.] Yes, Mathematics is a highly technical subject for the serious study of which most people lack the ability, whereas all people are capable of being serious Christians if they can overcome the impediments. Yes, some creative mathematicians have created their own valid calculi. And there are mathematical theories which are not simply the work of lone crackpots but have gained a significant following, yet are controversial within mathematics. Cantor’s theories of infinity were rejected by the mathematical mainstream when he first propounded them, and there is a minority view of the subject which has followers to this day.
These points are true but irrelevant. The point under discussion is simply this: is it right to emphasize the importance of mankind’s faulty presuppositions and unjustified intellectual autonomy? Yes, it is.
Presuppositionalism is relatively new, at least as a consciously-articulated doctrine. But there is a perfectly natural reason: It was developed in response to the never-before-seen phenomenon of large numbers of ordinary people possessing basically-atheistic worldviews, despite many of them professing to be Christians. Starting in the early 20th Century, and for the first time in the history of mankind, the typical member of a Western nation has basically atheistic presuppositions. For the first time ever, large numbers of ordinary people reject out of hand evidence for Christianity because they believe that miracles are impossible because reality is materialist.
And since most people are unaware of their presuppositions, even when they are pointed out to them, serious Christian apologists need to deal with presuppositions.
Old-school apologetics, which presents evidence without responding in a sophisticated way to worldview-based objections, still suffices for many encounters. And people often change their worldviews spontaneously and unconsciously in response to serious encounters with Jesus Christ and His Gospel. But for most Western non-Christians, false presuppositions and unjustified autonomy block their ability to accept the Christian message. A presuppositionally-aware apologetics has become necessary.