This would probably be a very easy question to answer, and yet at the same time, a fairly lengthy question to answer.
I will try to keep this as accessible as possible, and translate a lot of the jargon that gets used when talking about these things into more readily understandable ideas and explanations.
The easiest answer is: everything.
(Rom 1:20: 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 people are without excuse.)
Everything is evidence for God’s existence. And not just any God either, specifically the Triune God of the Christian Scriptures. We do not try to argue for a kind of generic theism, nor should we do so as we do not believe in a generic ‘minimum-attributes’ God, we believe in the Christian God!
There is not a single rock, blade of grass or sub atomic particle in this universe that isn’t evidence for God’s existence, and we shouldn’t be neutral about that, as if we would assess the evidence from a neutral standpoint and make a conclusion that God does indeed exist, and the evidence justifies that! Not only is that immoral, but it is impossible as we shall see later.
To quote C S Lewis:
“The ancient man approached God (or even the gods) as the accused person approaches his judge. For the modern man, the roles are quite reversed. He is the judge: God is in the dock. He is quite a kindly judge; if God should have a reasonable defense for being the god who permits war, poverty, and disease, he is ready to listen to it. The trial may even end in God’s acquittal. But the important thing is that man is on the bench and God is in the dock.””
Our natural temptation is to rally a bunch of evidences together (like the complexity of the human eye or other things), or theistic arguments (see Here as to why the theistic arguments when normally presented simply do not work) to answer this question and give them to an unbeliever, the problem is though, that an unbeliever doesn’t need more evidence. Not only that, but the believer, by doing these things is placing more certainty on those evidences than God’s existence, reducing God to ‘probably existing’ – even if this is a high probability, we do not serve a probable God, we serve a certain God. Further an unbeliever already has all the evidence he would need to know that God exists, but is suppressing the evidence that he already has:
Romans 1:18-20 : For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men who suppress the truth in unrighteousness, 19 because that which is known about God is evident within them; for God made it evident to them. 20 For since the creation of the world His invisible attributes, His eternal power and divine nature, have been clearly seen, being understood through what has been made, so that they are without excuse.
An unbeliever, according to God, has enough evidence through creation to know that He exists, but an unbeliever, in unrighteousness, suppresses that knowledge. The question then is, what good will it do to heap on more evidence? It would be like trying to put out a fire with petrol – any evidence that you give to an unbeliever will simply be suppressed further, or re-interpreted according to how they view the world (as one atheist said in regards to Christ’s resurrection, “Weird stuff happens!”). What they will try to claim to do is to stand on neutral ground, that their position is the neutral one, and that the believer should do the same and both look at the evidence from the same point. The problem is, that is assuming the very thing that the believer should be challenging an unbeliever on – their starting point and fundamental assumptions. The believer should challenge an unbeliever, and show them that given their starting point, given their assumptions, they couldn’t even argue with the believer about evidence! Everyone has worldview, there is no neutral position, a person is either for Christ or against Him ( ) in some other version of unbelief.
To quote Greg Bahnsen:
“It should come as no surprise that, in a world where all things have been created by Christ (Col 1:16) and are carried along by the word of His power (Heb. 1:3) and where all knowledge is therefore deposited in Him who is The Truth (Col. 2:3; John 14:6) and who must be Lord over all thinking (2 Cor. 10:5), neutrality is nothing short of immorality. “
If I poured water into a glass in front of a group of people, and filled it half way and asked the age old question “Is this glass half empty, or half full?”, I suspect I would get differing answers. Some would say half empty, some would say half full.
Why is there a discrepancy between their answers? The glass hasn’t changed, nor has the water or air content – and yet a number of people in a room cannot agree whether or not the glass is half full or half empty!
Why is it that two people can look at a particular fact, and come to wildly different conclusions?
Well, no doubt, when you look at certain things in your life, like the glass, you see things in a particular way, and another person views them in another way, yet the fact that you are looking at remains the same. The only thing that has changed is the person viewing the fact. Everyone has a way of viewing the world, or a ‘world-view’.
Everyone has a world-view, spoken or not – you may not have even thought about it, and are happy to live life as it comes, but if I were to ask you questions about it, you could probably tell me some things about what you believe or know to be true. Everyone has different experiences growing up, they have different beliefs about life, about morals or ethics, and about reality in general: What is the nature of reality? How do we know the things we know about it? All of these things contribute to the way that we view the world and the things in it – remember the glass of water? No one is unbiased, or ‘neutral’ in these things. We all have lens through which we view the world.
If we had a dispute about the price of a particular bar of chocolate that was at a particular shop, you and I could simply go down to the shop to see what the price was. Fairly straightforward! But not everything in life is this simple is it? We don’t solve a math equation simply by looking at it do we? No, we use our minds and logic to try to work that out. Nor do we measure the air pressure in the atmosphere by simply looking up, or trying to use logic to solve it as we would the maths equation – we’d need some instruments to do that.
All issues in life are not resolvable in the same way, so when we ask the question “What is the evidence for the existence of God?”, what is the method that we are using to determine what is and is not evidence? Enter our worldview again!
Each of us has a fundamental belief as to the basic nature of reality. Is reality only matter in motion? Is there a supernatural aspect? Is reality an illusion? etc…
This also influences how we know things – it would make no sense for someone who believes that reality is only matter in motion, only physical things and them moving, to use a supernatural method of finding something out – because for that person, the supernatural isn’t matter and motion, its something outside of those categories.
Inversely it would make no sense for someone who believes that they know things by a supernatural means to think that the basic nature of reality is matter in motion, because that belief wouldn’t follow from the method of knowing. Both of these things influence each other and work in tandem with each other. This is why someone who believes that reality is just matter in motion would use the empiricism to find out what exists. Empiricism is the idea that only that which can be perceived by our senses can be known (“Ill believe it when I see it” kind of attitude). Likewise, a person who believes that empiricism is the only way to know things, would be limited to looking for things that are just matter in motion. The supernatural is precluded at the get go, because it isn’t known by empiricism, nor is it simply matter in motion, it is outside of those categories.
There are many different views that control and determine the way we will consider facts in the world. None of these facts, like the glass of water, are without interpretation – the way we view the fact is interpreted by our worldview.
So given that we all have a worldview, and all facts and evidences in reality are interpreted through those particular lenses, how do we know which lens is right, how do we know which worldview is right? What worldview would allow us to know things truly? What worldview would enable us to be consistent in the way we believed the world was in principle, and how we lived in it in practice?
The question is not so much about which facts (or evidences), when evaluated, show God’s existence, but rather, it is a question of which worldview even allows for evaluation of facts to be done in the first place. There is no point in asking what the evidence for God is if we don’t even have a worldview that can allow for the evaluation of evidences!
In our worldview, there are beliefs that we don’t hold very dear to our hearts, those which, if challenged, or wrong, wouldn’t really change anything in our lives. If you believed that the price of the chocolate bar was £1, and that turned out to be wrong, that isn’t really going to shake your whole belief system! However, there are beliefs that we do hold very dear and close to our hearts – some so close that we don’t even think about them, they are just assumed to be true without much, or any questioning. These would be things like : are your senses reliable? Are your reasoning faculties valid? What is reality? How do i know what reality is? There are many many other aspects and assumptions that are so foundational to a person’s life and living, that if they were undermined, would throw their entire web of beliefs into confusion. These particular beliefs are called ‘presuppositions’. A worldview is a network of presuppositions.
If you were to picture what a worldview looked like, it may be a like a spider’s web. At the edge sides, you have individual beliefs – if one of those snapped, it wouldn’t really affect the whole web very much. But what about the corners? Or the centre? Those things that hold up the rest of the web! If one of those snapped, the whole web would be ruined! In the same way, if our presuppositions are shown to be false, the whole system of beliefs, (including those that influence the way we interpret facts and evidences) comes to ruin.
The question of the existence of God does not come down to individual instances of reality, to facts, or evidences, the question over the belief of God’s existence will come down to a battle over competing presuppositions. Which network of presuppositions, or worldview would allow us to even evaluate evidences, or even ask that question itself?
The Christian contention is that only the Christian worldview has the necessary presuppositions to make sense of the world, to make sense of our daily experience, the things that we take for granted, and allow for the evaluation of evidences. If rejected it would make nonsense of those things, and render them impossible.
To clarify: “We are claiming that the truth set forth in God’s revelation describes the way things really and truly are in the world. That is, we are saying that what God says about the world is the way the world really is. Any view or position that opposes what God has said is therefore, by definition, false and does not “fit” with the way the real world is…
This means that the views of any who remain in unbelief are, in reality, illusions. They do not and cannot make sense of the world as it really is.” – Scott Oliphint, Covanental Apologetics, Page (52)”
As the Dutch theologian Van Til wrote: “The proof of the existence of God is that without Him, you couldn’t prove anything.”
In part 2, we will look at the results of what we have just discussed, and an example in practice!