Bob is in a very tough time in his life; he's looking for something that's been missing, but he doesn't know what. One day, Bob meets a missionary on the street. They don't necessarily talk about religion or anything, but Bob gets a good feeling while he's talking to the missionary. He gets a good enough feeling that when the missionary asks if he can visit Bob at his home and teach him a bit about his Church, Bob says yes.
The missionary visits Bob and teaches him the basics. Bob feels that what the missionary is teaching is good. The missionary tells Bob about his personal feelings and testimony about his church, and Bob feels very strongly that what the missionary is saying is good and maybe true.
Now at this point, Bob can't be sure about the church. Can he really trust his feelings that much? Bob thinks that he can trust his feelings enough to do what the missionary asks him to do and read the scriptures and then pray about the truth contained therein, because: "If any of you lack wisdom, let him ask of God, that giveth to all men liberally, and upbraideth not; and it shall be given him" (James 1:5)
Bob reads the scriptures and the missionary visits him periodically to see how he's doing and teach him more about the church. As Bob reads the scriptures, he sees sense in the teachings there and he continues to feel that verifying feeling, telling his heart that it's true. He also starts trying to live a bit more like a good member of that church would. He tries getting rid of bad habits and sins and sees some changes for good. Finally, when he feels that he can't go longer without really knowing, Bob prays with full humility to ask God if what he's learned is true. This is Bob learns through the spirit of God that God lives and whatever the church teaches is true.
Unfortunately for Bob, he isn't done. He has to repent, which means feeling full remorse for one's sins and giving up old practices, before he can be baptised.
Later in Bob's life he is a good member of his religion. His life has taken a turn for the better. He is happier and more content with his life. The problems that made him turn to God in the first place are gone, but every time Bob prays he still feels the Spirit that gave him testimony. (That's not to say Bob doesn't have problems, but he can now turn to God for help and strength in dealing with his problems)
Bob sometimes thinks about the nature of the feelings that prompted him to join his religion. He's heard people say that all feelings are just chemical reactions inside his brain. Bob thinks that that doesn't mean they aren't as powerful or real. Bob believes that God achieves much -maybe all- through natural means (like evolution). Just because someone can look at Bob's brain and tell him when he is feeling the Spirit doesn't mean that it isn't there. Bob has also heard people wonder if maybe the "spirit" is just a programmed response to certain ideas in humans. If it is, why is that programmed response there, and why does it appear to be in all humans? (Bob has seen many people from all over the world join his church) If God brought humans about through evolution, it would make sense for evolution to have given humans a way to feel God's glory. Bob isn't sure about that line of reasoning, but when it comes down to it, the decent track record of Occam's Razor doesn't seem to compare to the power of his spiritual experiences.
Bob has also wondered about other religions when he isn't so strong in his testimony of his own. How does he know that some other religion wouldn't make him feel the Spirit (or whatever the other religion might call it) even stronger? Bob knows he can't practically sample all of the religions in the world, so Bob reasons that since he knows that this religion is good, being a member in it would just be preparing him for conversion if a better religion came along. He also reasons that he should look for good things everywhere in life to decrease the probability that he misses this better religion (if it exists). He also realizes that if the better religion doesn't have some sort of after-death conversion period he's screwed anyway so he might as well continue with the fulfilling life he has now.
Sometimes when Bob is reading the scriptures he comes across something that doesn't seem to make sense or is in discord with other passages. This doesn't bother Bob too much, because he knows several things. Firstly, he knows that much of the early scripture was written for a different people. The story of creation seems to be a dumbed down version of what actually happened for people who couldn't have understood it. Thankfully, Bob can still draw useful principles from these old stories by trying to understand what the ancient people were meant to understand. Secondly, Bob knows that the scriptures are very old and have been handled by a lot of people, some of whom might have messed some things up. Bob knows through the Spirit that the scriptures are all inspired (in a religious sense) by God, so Bob he sometimes has to seek out the inspiration behind the writing and not literal fact.
Finally, Bob sees people all of the time ranting about how religion removes individuality and teaches only obedience to authority figures. Bob knows this isn't very true. Being Christian (yeah, Bob's Christian), Bob knows that part of what Christ was fighting in his teachings was the Pharisees and their pharasitical obedience to law. Christ was a rebel and rejected the authorities to teach what he knew to be correct. Bob knows that testimony must be individual and personal. It can be helped by community, but it must never come from earthly authority.
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I think that's all I have on Bob right now. It doesn't answer many of the tricky little questions in this thread, it won't convert anyone (it probably won't even change anyone's mind; this is the internet, after all), and it certainly doesn't prove that some god exists. I just wanted to demonstrate what reasonable faith and religion looks like and hopefully explain what happens in a Christian conversion.
Phew. I've been saving that for a while. This probably isn't the right place. Heck, the internet isn't the right place.
[edit] I found
this article while Google-spellchecking 'pharasitical'. I thought it was a nice short read.
Now who knows what religion I am?