"Science can only deal with the natural. If you can't test it and observe it, then you can't do any science on it. End of story." [quoted from my original post]
I really don't mean to be snarky, but can you prove that statement scientifically? Is that proposition testable and observable?
Would you admit that there are some things you know which aren't testable and observable? How about your moral sense that someone, somewhere, is doing something you believe he should stop doing no matter what his biologically determined brain cells are telling him? Do you have that sense? Could you agree that it is evidence that at least suggests that you ought to believe human life is more than natural?
Did you read Stanley Fish's blog post a few weeks ago at the NY Times?
Fish is obviously not a conservative Christian theist, but I believe his thinking is incisive.
The Bible says in Paul's letter to the Romans that creation testifies to His existence and power. I pray that you will acknowledge this.
First off, being snarky in return, no, I cannot prove that statement scientifically because science never "proves" anything. It only allows us to draw conclusions which either support or falsify a hypothesis.
But yes, I will certainly agree there are things which are not testable or observable. Morality is an excellent example. I say that not because morality is a supernatural property of the universe, but because there's no such thing as morality. I posit that what we conceptualize as morality springs from a far more basic explanation: instinctual empathy.
As a social species, we need empathy to survive, otherwise we would be incapable of working with and living in close proximity to each other. The same holds true for other social animals such as lions or orcas. They show caring towards and a willingness to work with others in their social group, which gives them obvious advantages over their competitors and makes it easier for them to reproduce. I suppose you could argue that these animals are bound by the supernatural and absolute moral laws of the universe, but I find evolution to be a much simpler and more likely explanation.
Now apply the same logic to humans. We call people "good" if they contribute to the overall well being of the social group. Additionally, our brains have evolved an instinctual and automatic feeling of guilt when we detract from the well being of our society. Because this reaction kicks in without conscious thought only after our cognitive functions interpret outside stimuli revealing our transgressions, that feeling of guilt obviously comes from within the brain. You could claim that is comes from the nature of your "soul". However, I feel the more convincing argument is that social creatures with such a response hardwired into their brains would be more successful because they know to seek forgiveness, thereby keeping their place in the society.
In contrast, look at what happens to those who break with our expected norms of empathy and guilt, leading them to harm others and show no remorse for doing so. These transgressors become shunned, imprisoned, or executed by the social group. It makes sense that only those humans who exhibit sufficient empathy and a sense of guilt would be able to reproduce consistently within such an environment, thereby making antisocial behavioral traits less common within the population, which in turn makes constructive behavior more common. In addition, this rise of commonality creates the appearance of "universal" moral beliefs.
Furthermore, we do see occasional mutations where individuals do not display any sort of empathy. We call them sociopaths, and we can actually measure their lack of empathy through fMRI scans because the part of the brain which normally controls empathy shows very little activity compared to normal brains.
To put it simply, our brains have evolved to be empathetic because it allows us to interact constructively with each other. Without it, we cannot function as a society and we would live more like mountain lions, roaming our territories alone, only meeting to mate. Our obvious physical limitations make survival in such a situation unlikely at best. Therefore, like bears hibernating for the winter or sea turtles knowing when to return to their mating grounds, our empathy is an instinct essential to human survival and reproduction.
So where does that leave morality? Just because I'm fairly certain sociopaths have no control over their antisocial impulses, does that mean they shouldn't be held accountable for their actions? Of course not. But that brings us back to science's role in such decisions, which is quite minor because science is a tool, nothing more, nothing less. Used properly, it can tell us how the universe works and why things came to be through naturalistic reasoning. However, it cannot tell us what to do with that information. That's up to us. For example, science can tell us about the potential energy locked within subatomic bonds, but we decide if we want to use it to produce electricity or make nuclear weapons. Similarly, just because science can tell us that a sociopath has little control over his antisocial actions, that doesn't tell us what we should do with the sociopath. That's where philosophy comes into play, which we base upon our instinctual sense of empathy. Even then, our empathy varies. Some prefer revenge, seeking execution for the sociopath. Others advocate finding a way to alter his brain, thereby curing his lack of empathy.
Now, when you boil them down, religions are just philosophies which attempt to tell people how to live within a society. Every religious person will tell you that those proscriptions come from a god or gods because, deep down, we all "know" right from wrong. Sure, most of us feel that urge to be constructive, but is that because God did it or because we've evolved the instincts for it? I lean towards the latter.
Does that mean I think morality has no place? Absolutely not. First, I like to be constructive and contribute to society and treat others well. Just because I know it's simply my instincts talking doesn't mean I'm disinclined to follow them. That's the great thing about understanding why we feel the way we do. We can chose to follow those instincts that make us feel good and help others while also choosing to resist the other instincts which are harmful, even when it might make us feel good. For example, we all feel some degree of prejudice towards others. However, if we know that's a product of our ingrained instincts and competitiveness, we can resist it and refuse to yield to our base emotions. Religion attempts to do the same thing, but it adds artificial constructs such as God, Satan, and Hell as enforcement mechanisms while claiming absolute truth. I see no need to bring extra complexity to the explanation, and I certainly won't claim absolute truth. Frankly, I feel absolute truth is beyond our means to comprehend.
Also, I appreciate the link to Stanley Fish's column because I had not seen that before. While I understand what he's saying, and I agree with him to an extent, I feel the religious foundations he appeals to are simply man-made philosophies as I outlined above. However, there are secular philosophies which can provide the same basis for argument. Sure, secular philosophies don't make claims to absolute truth, but I think the religious claims of such are fundamentally wrong because religion is an unscientific attempt to codify and explain, in the case of morality, an evolved survival mechanism.
As for the last point, I'll acknowledge God's role in creation when He gives me sound evidence to do so. Until then, I have no need for that hypothesis.
I have a post from 2007 addressing some of these topics here.