One of our primary points of contention, and the one we always came back to was whether or not thoughts arise from purely physical processes. I know little about neuroscience, so it was a difficult subject for me to argue. Of course, my coworker knows even less about it, so that was a moot point. Anyway, I maintain that thoughts are the result of physical processes, and I feel the evidence fully supports it. The Christian obviously feels differently. Even when I point out that specific portions of the brain show electrical activity during thought formation or that damage to specific regions will render a person unable to feel the emotions or thoughts generated by that area, the Christian insists that the evidence is only correlation, not evidence of origin:
but if you cannot explain physically where a thought comes from originally (NOT HOW IT'S EXPRESSED) then should you hold to your materialistic beliefs or look for another explanation?
In response, I pointed out that we simply don't understand the workings of the brain well enough yet to properly "read" thoughts. Why dismiss a possible and explanation before it's falsified, especially when there's a strong correlation? In response, the Christian accuses me of taking it on faith that we will eventually be able to read thoughts simply because I have an irrational belief in materialism. As he says it, we can't completely explain the origin of thoughts now, so there's no reason to assume natural causes. We automatically have to go with the supernatural.
While the fact that I have a "belief" in naturalism is certainly true, we can only build judgments based on our beliefs and experiences, I feel the history of science shows that you can't assume anything is unknowable, especially when natural causes have explained so much already. Just because people couldn't imagine or even measure the presence of relativity before the 20th century doesn't mean it wasn't a property of the universe.
Nevertheless, the Christian went into a diatribe that one must consider the supernatural for things we cannot measure, such as thoughts. Really, it was nothing more than a "god of the gaps" argument dressed up in a way that sounded philosophically pleasing enough to make his faith sound science-based. When I pointed the obvious fact that his insistence on the supernatural is wholly dependent on his preferred beliefs, he threw the following down:
philosophical naturalism... not science. I'm honestly kinda disappointed you won't consider intelligent causes
Despite the gross misunderstanding of science, the Christian's declaration of his superiority kind of pissed me off. I didn't say anything about it, and just let him continue on his tirade for a while. I made a couple of attempts to further explain my argument, but the Christian was pretty much done with the debate at that point and decided to call it a night shortly after that. I never expected any sort of victory. We view the world in fundamentally different ways, which means we will never agree on certain aspects.
Nevertheless, the fact that I kept it cool and reasoned, while he was the one to make it personal gives me a small degree of satisfaction. No, it won't change a damn thing, but I'll take it. Still, I think I'm about done talking with him about religion. Now that he's made his disdain open, I see little reason to continue.