How do you know God exists?
Once upon a time there was a young boy who lived in a big house. He had loving, caring parents. Mum made sure his meals were prepared, clothes put out, and his bed made. Dad often played cricket with him in the backyard. One day he went to school and, in the class discussion, he said to the teacher and the class, 'I don't have a Mum or Dad. I'm just here by myself.' The rest of the class started to laugh but the Teacher stopped them and said gently and kindly, 'But you must have a Mum and Dad. You wouldn't be here if you didn't have a Mum and Dad.'
In the same way it can be said that we wouldn't be here if God didn't exist. The most basic thing we can say about God is that he is the Creator of all things. The Bible also tells us that 'in him we live and move and have our being.' Since these are basic facts about God, we can say that we ourselves [not to mention the Universe and everything in it] are the objective proof for the existence of God. We need go no further than the existence of ourselves for proof for the existence of God. If we want to go further, we can point to anything--from the farthest star to the minutest organism--and say, 'That's proof for the existence of God.'
Some people don't feel very comfortable with this line of thinking. They will tell us that we're assuming what has to be proved. They would like us to be more neutral about this whole matter and start by assuming God did not exist. That would be about as sensible as the Teacher saying to the class: 'Now boys and girls, this is a very interesting question. Let's all say we don't have mothers and fathers. Let's say we just appeared on the scene--and then we'll try to prove we have mothers and fathers.' I hope someone would say that if you start off assuming they don't exist, how will you prove they do. In the same way if you start off assuming God doesn't exist, you'll never prove that he does!
People who want to doubt or 'disprove' the existence of God usually want to restrict their doubt to that question. But why? If you can doubt the existence of God, surely you can doubt the existence of yourself. In fact years ago there was a very famous philosopher called Rene Déscartes who was a real 'doubter.' He doubted the existence of everything—even himself! He asked, how can I prove I exist? And his answer was: Cogito ergo sum, I think, therefore I am [not, iMac!] He thought that his thinking guaranteed his existence. But even poor Déscartes was not a good enough doubter! He didn't really doubt himself. Otherwise he would have only said, 'There's some thinking going on.' If he had done that, he would have ended up in an asylum.
The upshot of the whole matter is this. If we're going to question the existence of God, we shouldn't really stop questioning until we're questioning everything--even the reliability of our senses, understanding and existence. And this is really where human thought that starts out denying God ends up. It tries to make sense of the world without God, and finds out in the end that it can't even make sense to itself. It ends in emptiness and meaninglessness. At least some non-Christian philosophers have been able to see that quite clearly. The famous German philosopher, Nietzsche, declared that if God is dead, man is dead too; the one gives meaning to the other.
The basic reason why people want to make the existence of God a problem is because they don't want to face him. And they think that the invisibility of God gives them a good excuse. Things seen can't be doubted; things 'unseen' can be. But this is quite false. Often in courts of law people give contradictory evidence about the same event that they have seen. Besides, if we carried that principle through consistently we would have to deny a lot of things we take for granted like the mind and thoughts, which are invisible. But we can go even further. God has revealed himself in this world; the Unseen has become Seen. Jesus Christ was [and is] God in human form. He demonstrated this in the things he did. But did people say, 'Here is God in human Form!'? Not at all. They disbelieved him, criticised him, and finally crucified him. His 'visibility' didn't make any difference at all.
In a nutshell, we can say that every single thing in the Universe is evidence for the existence and richness of God and ultimately, all historical and archaeological research, and all the findings of science in every field will bear testimony to his existence, and the truth of his Word, the Bible. Even today in all these areas there is a tremendous amount of evidence that shows quite clearly the truthfulness of what God has said in the Bible about the world, life, and his Son, the Lord Jesus. At present there are things we don't understand. But this is only to be expected. The Creator is infinitely greater than what he has created. As we study the creation, and the Bible, we will come across things which will stretch our understanding to the fullest, spur us on to greater research, and make us aware of our limitations. But when history has run its course, it will be plain that everything in us and about us, and in the Bible proclaims the existence of the One who alone has life in himself.
But if the evidence is so clear for God's existence, why can't it be seen by everyone? To answer that let me tell a story about the Valley of the Blind. A man was out walking one day and fell into a valley where only blind people had lived for generations. He talked about the wonderful things he could see--the colour of the flowers; the beauty of the sky; the glory of the sunsets and many other things. They said he was quite mad. They had never 'seen' any of these things and believed he should have an operation on his eyes so he would be like the rest of them! So it is with the evidence for the existence of God. Its there in all its richness and awesomeness. But if we're blind it doesn't matter how much there is. We will not see it, and, as the saying goes, 'there are none so blind as those who do not want to see.' And until our eyes are opened we will not see, even if someone should rise from the dead.