How Much Proof Is Enough Proof?

I was talking to a lady over breakfast the other day. It was a church breakfast, where some people had been invited who were “casually curious” about matters of faith and the existence of God. I was there to answer any and all questions with grace, and not get too bogged down in the jargon of Christianity, since doing so might “scare them off” as the pastor put it. The lady sitting near me asked about proof. She was a scientist, and was used to dealing in measurable matters of proof. But her young daughter’s curiosity about the measurable truth that some things live and die had prompted her to come to our breakfast with questions of her own. She struggled with proof of God’s existence.

So, we talked about the nature of scientific proof. Having worked myself as a biochemist for several years, we had some common ground on which to explore the topic. It didn’t take long for her to admit that much of what we call scientific proof is actually only supported by indirect evidence. In the lab it is quite common to “prove” the existence of something not by measuring the thing itself, but by measuring what it does, or what it produces. Then, by measuring that product or effect, we look behind the results and take an educated guess at what might be the likely cause. That’s even the way things are with the famously-broken and soon-to-be-fixed Large Hadron Collider. When and if they fire that thing at full throttle, they will not measure what it makes, but rather the traces of stuff that shoot off as a result. That’s actually indirect proof, but it’s the only kind of proof they expect to get, and it’s actually all they need to be happy.

All this made perfectly comfortable scientific sense as we enjoyed our conversation between bites of bacon and egg. So then I asked if certain observable phenomena might serve as indirect evidence for God’s existence. The kinds of observation I had in mind were familiar to her, but she had never thought of them as evidence or proof. Things like how we have been invested with a sense of what’s fair, and what’s not fair; or when someone’s life just turns around, and they adopt a brand new set of decent values and priorities; or when people are sacrificially generous with their money, or even with their own lives? Ethics, dignity, and morality can be observed, but they can’t be explained on purely natural grounds. In fact they don’t really make sense on natural grounds, that’s why we say that people who don’t show them are behaving like animals!

What I eventually came around to was the conversation Jesus had with Nicodemus in John chapter 3. When Nicodemus couldn’t grasp the significance of the ministry of the Holy Spirit, Jesus appealed to indirect evidence: “The wind blows wherever it pleases. You hear its sound, but you cannot tell where it comes from or where it is going. So it is with everyone born of the Spirit.” (John 3:8) The effects of God point back to the existence of God. It is by His visible works that we have proof of His invisible character: “For since the creation of the world God’s invisible qualities—his eternal power and divine nature—have been clearly seen, being understood from what has been made, so that men are without excuse.” (Romans 1:20)