Petitio Principii. Again, I ask why?
Don't take my word for it; take Karl Popper's.
I'd rather reason through this than appeal to "authority". Many authorities disagree on this, so I would like to reason with you directly.
All right, reason it out. I propose as a "scientific" belief that all rivers have an invisible nymph that looks after the river. This is, in principle, something that cannot be tested. Now, you're a scientist, and you want to make your mark on the world by working on "nymph theory." Whatcha gonna do with this "theory"? What's your first move?