Just thought I'd throw this in. I may have posted it before. Can't remember.
If I make the statement "I have magical powers", and cannot offer evidence to support this, there are various possibilities about what is "true".
I'd say there are four main ones, with possible refinements, unless anyone wants to offer any extras.
(a) I have magical powers, and for some reason best known to myself am choosing not to exercise them right now.
(b) I have magical powers, and am demonstrating them in some way which cannot be empirically tested in the physical world, or which is too sophisticated for you to understand until you have read up on magicology.
(c) I do not have magical powers, but am convinced I do - i.e. I am deluded or at least have convinced myself that the statement is true on some level, or need to believe it for some reason.
(d) I do not have magical powers, and am well aware I do not - i.e. I am consciously fibbing for some reason.
Now it's fair enough for intellectual purposes, if you like, to say that the chances of these being true are absolutely equal, and not to choose between any of them because we cannot, ultimately, know - nobody can prove if I have magical powers or not.
But on a practical level, concerning the way we behave in the world, it's likely that most people will veer more towards either (c) or (d). It's not impossible that (a) or (b) could be true, but they are both, in practical terms, vastly unlikely given what else we know about the world.
My arguments for having magical powers may be internally quite coherent and could convince the gullible. But that doesn't change reality - we have to assume there are no "magical powers" until and unless someone can demonstrate them.
Similarly, the arguments against my having magical powers may sound frustratingly unconvincing - but again, that doesn't change the fact that the initial claim is fictitious until shown to be otherwise.
I hope this goes some way towards helping people understand my position.