My Answer: I get asked this question nearly every time I publicly debate atheist scientists. The atheist(s) posing this question anticipate(s) that my answer will be that no potential scientific discovery would ever cause me to abandon Christianity. They then would be correct to conclude that my faith is not based on physical evidence. A belief system that is not falsifiable is simply wishful thinking.
There are several potential scientific discoveries that if proven beyond any reasonable shadow of doubt would, in my opinion, be catatrophic to the Christian faith. Here are four examples:
- proof that the universe had no beginning
- proof that humans compared to all other Earth life are not exceptional; proof that humans differ from all other animals only by degree and not fundamentally in kind
- proof that there are humans who have never expressed any sin or evil
- proof that Jesus of Nazareth did not rise to life from death
Personally, I do not see how Christianity could survive as a rational truth claim if any one of these four potential scientific discoveries were proven true. Concerning the fourth example, the apostle Paul in 1 Corinthians 15:13-19 agrees.
My being quick to admit potential scientific discoveries that would shatter my Christian faith strongly communicates to my audiences that my faith in Jesus Christ indeed is based on physical evidence. It also allows me to graciously turn the tables. Having volunteered without hesitation where potential scientific discoveries would force me to abandon my faith in Christ and in the Bible, I can ask the non-theists on the platform with me and in our audiences what potential scientific discoveries would persuade them to abandon their non-theistic worldview and adopt theism and, specifically, Christianity.
Typically, when I ask non-theists to list a few potential scientific discoveries that would cause them to become theists, they claim that they cannot think of any, or they will say that there are no such possible discoveries. Such an admission establishes that they are non-theists not for rational reasons but for irrational reasons.
I have found that the most common irrational reason is some past hurt(s) they experienced at the hand of someone who claimed to be a Christian. In that event, presenting additional rational reasons for my faith in Christ can be counterproductive. I have learned that I must stop and invite them to tell me their story, compassionately listen, and gently suggest ways that their past wounds can be healed.
Frequently, when a non-theist struggles to come up with a potential scientific discovery that would be catastrophic to non-theism, they ask me if I can suggest one. The advantage of the four potential scientific discoveries I listed above that would refute Christianity and belief in the Bible is that the reverse of each refutes non-theism and establishes theism and Christianity in particular. Atheism and agnosticism are indefensible if we can show beyond any reasonable doubt that 1) the universe had a beginning, or 2) humans compared to all other Earth life are exceptional, or 3) all humans are sinners, or 4) Jesus of Nazareth really did rise from the dead.