Yes. I observe millions/billions of stars shining brightly in a cloudless New Mexico sky. Science can speculate what they are based on understanding of our own sun. But there is no way to be certain when we have no way to test whether all those other stars are of the same chemical makeup, consistency, or behave as our sun behaves. But we know they are there.
Actually, that's wrong. We can and have tested those far away stars and shown exactly what they are made of. We can also explain their actions. we call them dwarves, giants, pulsars quasars, etc.
Yes there is. It's repeatable, observable, measurable, and doesn't defy the laws of physics.
As Meister posted, he knows what he saw. He knows that it was real. He cannot prove it to anybody using any known method, scientific or otherwise. Nor can you prove that he didn't see it or that it was not real.
Meister never stated what it was he saw, so therefor we cannot surmise that his observations prove anything at all.
If, for example, he stated that he saw a ghost, I can prove that he didn't, but I wouldn't try to claim he didn't see anything. I'd just prove that it wasn't what he claimed it was.