Long, long ago...
Bob: While I was at the clinic the other day being treated for plague, I overheard this jagoff trying to convince people the world was round. Can you believe that?
Steve: What was his evidence?
Bob: That's the best part, he didn't have jack. Oh well, when he falls off the planet, don't come crying to me.
What may be considered evidence for or against something has to be discovered just like anything else.
I understand your anology.
But my point is that there
is evidence for all scientific theories! (like for example you can see that the Earth is round if you look from the top of a mountain)
But there is
no concrete evidence that there are ghosts, or Aliens watching us, requiring us to wear tinfoil hats.
I understand that this doesn't prove that there aren't ghosts. But the possibility of those existing is so small that it should never be seen as an explanation for a sound you hear at night.
Extraordinary claims need extraordinary proof, I say!