As a disclaimer: I will not be discussing any specific religions, just the mere existence of a God.
So whenever I tell people that I study neuroscience and that I am a Catholic one of the common reactions is “Really!? How can you study science and believe in God? Hasn’t science proven that there is no God?”.
Anyone who has studied science or the so called ‘scientific method’ will most likely agree that, science can not prove that an ‘object’ does not exist. In a very strict sense of the meaning of ‘proven’, science has not proven anything at all. Firstly scientists are busy trying to disprove null hypothesis. Secondly they do that on the basis of probability. Now the deal with scientific hypothesis is that they have to be falsifiable.
The hypothesis ‘there is a God’ is not falsifiable. The scientific method cannot show that something does not exist. You can not go to an e.g. lingerie shop and say “look there are not any lions here, so lions do not exist”. One could do that for every single space in the whole universe and in all dimensions and still one could be wrong as one might not simply have the tools to do that. Following from the previous sentence it should be pointed out that only because we can not show that something exists does not mean it doesn't e.g. for centuries people did not believe in the existence of viruses, but that did not mean that they did not exist. And it would not surprise me if tomorrow scientists come out with completely new theory regarding the existence of viruses. It is also the case that null hypothesis usually imply the lack of something. In science it is usually a null hypothesis would say: there is no significant difference between x and y. Hence ‘there is no God’ seems like a better and more practical null hypothesis. Although it also does not imply any difference between two phenomena.
Before we move on with that null hypothesis a couple of words have to be said about the phenomenon of significance in science. So I used to think that science was quite efficient at asserting things and more useful than most of humanities, but the more science I learn the less I think that is the case. Besides the fact that loads of high profile science is actually low quality, the fact that something is deemed significant in science if it is statistically likely to occur less than 1 in 20 times by pure chance. It would not be such a depressing thought (but still depressing) if there was a good reason for choosing 1/20 - but there is not! Pretty much a bunch of guys who though that they were clever must have just decided on it and frankly truth is neither defined by a democratic vote nor simply by someones authority. But whether through our faith or our pragmatism I still think we managed to learn a fair bit about the workings of this world through this flawed method.
Moving back to the null hypothesis that there is no God... Well to disprove this we would have to present evidence that is likely to arouse by chance not any more often than 1/20 times... But lets skip that notion since it is flawed anyway and lets just think about the evidence. It is unlikely that we could measure God if the cases made by a couple of religions were true, if God was measurable, He would probably be controllable and that does not seem to mach most criteria of a deity. It is often argued that Goedels proof shows that there is at least one God, but it had been subjected to loads of criticism and whether he managed convince himself still remains a question. What I can comment on is that any evidence that can be shown is merely proxy (and we can never be sure if proxy do their job correctly). Many scientists (not that authority really matters) argue that the complexity of the universe and its presence can be used as arguments for Gods existence but there are alternative explanations (often not incompatible with Gods existence) that can be used to explain those events. Nevertheless those theories of Gods involvement are not really falsifiable by science. There exist also arguments proposed by religious groups to try to help their cause, this is usually material or historical evidence, that one should not dismiss straight away (one can read Lee Strobels book for some examples).
I think it can be seen from this that all those arguments require faith and, but frankly so does the stance of atheism. It is a judgement call. I have also proposed that atheism is a very radical stance and since it might be the case that the hypothesis ‘there is no God’ might not be falsifiable due to practical reasons as well the hypothesis that ‘there is a God’. The only reasonable stance seems to be agnosticism, as all other sides require some faith.
Still that does not answer the question why I believe in God. Well I like to search for the truth (and I do question my faith). I search for truth to be able to live a better life, to be able to make better choices. Reason is probably the one single biggest tool that we have available to assess the truth. But the knowledge that we obtain (and can further assess) is usually obtained by some sort of revelation. As a neuroscientist I am well aware that our senses and our perception can be tricked and even trusting them requires faith and we do it for pragmatic reasons - they seem to work. Great discoveries were made by people who questioned what was known and could be affirmed by reason (and still many leading scientists question what the public perceives to be scientific facts). This often requires faith into ‘weak’ evidence and pursuing the exploration of them. And I trust the evidence for God (in my opinion it is quite strong), the same way I trust in the scientific method being able to tell us something about the world. And as much as pragmatism does not make anything good I think if we do not want to go crazy, we seem to need some in life.