I believe in God.
I will say that I believe in God for three reasons.
But I will hasten to add that there is something weird, and probably misleading, about saying this. It’s weird and misleading because I think God is really there and really interacts with us. Imagine how you would react if you were asked what reasons you have for believing in the real existence of your friend, or brother, or even mother. After staring at your interlocutor as if she’s plainly daft, you may stumblingly attempt to come up with your “reasons” for believing in your friend/brother/mother. But notice how weird and misleading the whole enterprise would be. It’s not like you believe in your friend/brother/mother because you have some fancy “proof” that (s)he exists. Only a philosopher would “reason” about such a thing at all. You believe in the real existence of your friend and brother and mother because of your interactions with them and because of what you have been told about them, not because you have “reasons” for believing in them. I also bet that the “arguments” you came up with would not be very good from a logician’s point of view. Your questioner would probably remain quite unconvinced, and even wonder how you could believe in these people on such flimsy evidence.
Imagine further that you believe your friend/brother/mother is in the next room listening in on your conversation. I bet this would make you, at the very least, a tad uncomfortable. The conversation would seem, at least borderline-insulting to its subject.
Having said this, I offer my “reasons” for believing in God.
First, it seems to me that the existence of God provides the best possible explanation “of everything.” It would provide the best possible explanation of the existence and nature of the universe, including all its contents, and including the nature and history of us humans.
Secondly, believing in God seems to provide huge practical benefits; it can give us well-founded hope, confidence that we all actually matter, and confidence that behaving ethically—treating each other well—is actually worth the bother.
And thirdly, well, I just find myself believing–I suppose as a result of various types of experiences. If God is there, it strikes me as unlikely that God would set things up in such a way that those who happen to be good at reasoning about God would have a leg up in relating to God. It strikes me as much more likely that God would give us all a basic latent instinctive intuition of God, perhaps triggered by various kinds of experiences. So as my knowledge of everything, really, comes from my nature, triggered by various experiences, I have no good reason to believe that my inclination to believe in God is not actually a reliable indicator of God.
I do not offer this as an argument or evidence of the existence of God. I am only citing what I am inclined to believe is a root cause of my belief.
Of course, I owe you a great deal more explanation of these perspectives, and even of what I mean by ‘God.’ But I’ll leave those things for other days.
For a far more complete explanation see: Questions For Those Who Doubt