Jitro wrote:
Do spiritual things exist? How can we say that everything is physical? Is it any more possible to prove that than to prove that all life in the universe originated on Earth?
Spiritual things all boil down to belief.
But then, so does science. At the root of science is the belief that science has validity. You can't use science to prove that science has validity. You must use some other form of ratiocination.
The fact that some people belief that they have been abducted by aliens isn't really up for dispute. They believe it, whether you believe it or not. And the fact that they believe it exists. You can't really argue that the belief in alien abductions doesn't exist. At best, you can only argue that there is insufficient proof that alien abductions happen, even though a bunch of people claim that they do.
In the sense that the belief in them exists, so do god, alien abductions, santa claus, and the honest politician.
It's also clear that alien abductees have had some sort of an experience. I'm not sure what "really" happened to them, or what their experience would have looked like to me if I'd been present, but it's pretty clear that they have had some sort of experience. (wikipedia: "black swan"). It's also not clear to me how you or I would describe our experiences if we'd had the same experience that the abductees are describing. But it's likely that we'd describe it somehow, even if our descriptions were radically different.
In all of those senses, spiritual things do exist.
But then, the number "1" doesn't exist in the physical world either. It's an abstraction. A pure concept. A model by which we evaluate the world. The very idea that 1 != 0 is taken as an assumption in modern science - a presupposition, a belief. Without it, the rest of mathematics tends to fall apart and with it, mathematics seems to be quite useful.
When it comes right down to it, we don't have any scientific evidence to prove that "reality" exists. You could all just be a figment of my imagination. Or I could be a brain in a vat. Or dreaming.
Are dreams real? Are they any more or less real than the number "1"? Can you prove either assertion?