That does fall within the realm of science; there is a theory supported by physical evidence, and the predictions are repeatable, etc.
After a couple of attempts, I am apparently failing in the task of communicating the distinction between science/physics and metaphysics. Let's not leave it to my attempts, then. There is enough written by real philosophers of science/metaphysicians. I'm only summarizing and paraphrasing in any case. I don't blame you for wanting a more complete logical proof. . . .
I know Jesus. Jesus is a friend of mine
The point I was aiming for (for future reference): people approach their Christian faith from a lot of different angles, and you might not want to unintentionally (when it is not necessary to the argument at hand) disparage someone's loyalty to their best friend in their presence (during a discussion on FR in which many different people are engaged). Probably moot at this point, as we seem to have this thread to ourselves! . . It actually might be time to branch out into broader discussions on other threads again . . . ;) .
Others could (and DO!) say: Not believe in the Aesir? Of course I believe in the Aesir. I know Odin. Thor is a friend of mine
However, (since you brought it up) you must be aware that the God of Christianity, especially in the Person of Jesus, is more personal and approachable than the god(s) of many other religions (e.g. Islam). Knowing a person is one way to "know" that he exists. . . . In Christianity, it is doctrinally possible to enter into a personal relationship with God. (Although the agnostic would say, they are just making it up!) Truth in the Christian understanding is not only rationally knowable, Truth is a person WHO is knowable. That dimension is attested to by many people's mystical and spiritual apprehensions. Not that I think you would find that kind of biographical and experiential "evidence" convincing, until/unless you satisfied your intellectual skepticism about God's existence in the first place. At least, that is the order I would take it in . . .
Which means that at that level, God is equally as likely as, say, the tooth fairy,
For some reason, I am visualizing little "straw" tooth faries and movie characters swarming about . . . ;) Hey, maybe Rumplestiltskin created the Universe out of straw!?