Can You Prove that Christianity is True?
People sometimes ask if I can prove that Christianity is true. And the honest answer is 'no, I can't.' But this is not quite the game-changing admission that they might like it to be. It turns out that ‘proof’ is quite a slippery idea. There is very little (if anything) that we can prove absolutely. So we would do better to think in terms of how much evidence there is, and what is the best explanation of the evidence. On the face of it, some kinds of knowledge are more certain than others. But when you look more closely, things are not that simple:
(1) Mathematical knowledge
With mathematical knowledge, if you understand something, you believe it. Once I’ve seen a proof that the angles of a triangle add up to 180 degrees, I know that for a fact, at least based on the axioms I start with.
But even mathematical knowledge is not as certain as it seems. One mathematician thinks they have proved a particular theorem, then another comes along and shows that the proof is wrong.
(2) Scientific Knowledge
With scientific knowledge, the evidence is public. In principle, anyone can prove it, anywhere, any time.
But scientific knowledge is not as certain as some people would like us to think either. For hundreds of years, people thought Newton's law of gravity had been proved - until Einstein came along with the Theory of Relativity.
(3) Personal Knowledge
I know that I am sitting at my computer. I know what I had for breakfast this morning. I can’t prove these things to someone else, and no-one else can disprove them to me. That’s true of all my personal experiences, and all my memories.
But what I 'know' personally can still be wrong. I may think I can see a car in the bushes, but it turns out to be just a pattern of branches. I may think I visited New York, but I am mis-remembering.
The most important things of all come to us through relational knowledge - because another person chooses to make themselves known to us. So I would not know that my wife loves me, if she did not tell me, and show it by the way she acts towards me. Knowing God is like this.
(4) Historical knowledge
Historical knowledge depends on the testimony of others. This may make us unreasonably suspicious of it.
But almost everything we know depends on the testimony of other people - things we have heard, or read in books. The amount that we know first hand is really tiny. So we cannot dismiss something just because it comes to us through testimony.
There are some historical things that we can be fairly sure about. Others, not so much. I am reasonably sure about the D-Day landings and the sinking of the Titanic, but much less sure about some of the things that are reported about Alexander the Great. For more recent things, we may have sound recordings or videos - but even these can be forged.
When it comes to historical matters, our view is based on how strong we think the evidence is. And different people will assess the evidence differently, and come to different conclusions.[1] This is not a fact about Christianity. It is just a fact about history. It is relevant to Christianity because Christianity claims to be based on things that have really happened, in history. This is why the historical evidence is so important.
So - can I absolutely prove Christianity is true? No, I can’t. But then I can’t absolutely prove anything important.
Is there good evidence for Christianity? Yes, there is.
[1] This difference is driven partly by people having different worldviews. This affects the assumptions they bring to the evidence. So, for example, if someone believes that there is no God, and no supernatural world - nothing beyond the physical world - they are unlikely to accept any amount of historical evidence for a miracle. They will always find some other explanation to be more plausible. This does not have anything to do with how good or bad the evidence is. It has everything to do with their prior assumptions.
