OK, so you're proposing prayer as an experiment to determine the existence of God. That's a simple enough methodology. But, it doesn't make a prediction: after I've prayed, what result should I expect? What constitutes a positive result, and what constitutes a negative result? If I don't see some sign immediately, is that evidence that God doesn't exist, or should I wait longer? How will I eliminate external factors - if lightening strikes the moment I finish praying, was that a sign, or is it just stormy today?
Logically, what
would come next? You can certainly make a prediction... but since Christianity is based on faith, your predication must account for that - it can still be logical.
1) You would continue to sway on the doesn't-exist side - I mean why wouldn't you?
2) You don't know
what would prove to you without a doubt that He exists, so you can't predict what might happen.
3) You
can however predict that either
3a) He doesn't prove it to you, so, well, nothing as far as you're concerned.
3b) He proves it to you. And since you don't know what to look for/eliminate, you already have faith it will be in a way that is unexpected. It should be fairly obvious that while you don't need logic to have faith, and you don't need faith to be logical, logic and faith are
not mutually exclusive...
You mean the book by CS Lewis? Unfortunately his arguments are all based on pretty unsound premises - for example, he assumes that moral laws are intuitive and inborn, rather than learned. He also suffers from a pretty severe case of anthropic bias (e.g. the water argument - if water weren't abundant then we wouldn't have evolved to make such heavy use of it, if we'd have evolved at all).
I'm sorry I meant
Basic Christianity.
That is one reason, but it's not the important one. The important reason is that it doesn't attempt to explain how it works, beyond some shallow claims about water having memory. Because it doesn't explain how it works, it's impossible to determine which details matter. For example, what is the correct quantity to administer? Is there a limit to how much a person should have, or how frequently they should have it? If two different homeopaths give you conflicting instructions, how do you figure out what to do?
If it worked, we would almost certainly put more effort into figuring out how and why it works. Chances are we'd still be wrong - in school I learned there are 5 definitive areas of taste on the tongue and now they say that's not true (or you can just try it yourself). On the other hand, if you believe in Christ, you tend to believe God tells us how and why it works. And again proving something becomes essentially irrelevant... we (should) move on to the next logical step... living it. No?
I don't accept the concept of 'knowing oneself well enough' to be certain about that kind of thing. On average, we're wrong about ourselves in much more significant ways than we're wrong about the world around us.
Ok fair enough, but if everything inside you changed ie. your desires, your convictions (call it what you want), and even stuff that once seemed illogical seems logical now as if a veil was lifted, you don't really miss that kind of thing, or get it wrong. Same goes with people around you. Ie if heroin addict Joe goes through the best programs, relapses every time, goes to jail multiple times, and always goes back to heroin, and then one day stops forever including other sensual substitutes, and claims it was God, there's
slightly more evidence. When this happens in a variety of situations, with a variety of people that you do "know quite well", with dramatic changes about them which most would consider good changes... the evidence stacks up more and more. Each case can be explained in and of itself, sure, but when it happens to
you, they start to become pretty credible... this is where I'm coming from and it's rather hard to show that aspect without you actually experiencing it I suppose.