On the one hand, there are no logical methods to prove the non-existence of a thing. If telepathy, telekinesis, ESP and other such so-called supernatural phenomena do not actually exist then there is still no way can never be a way to prove that they don’t. That is to say, neither I nor anyone else can state with provable certainty that God does not exist, and that he does not live in an invisible pink teacup that sits on the other side of the Moon. Anyone can say, “That’s not true!” but no one can prove that it isn’t.
However, the other side of that coin is that if someone wants to prove that these things do exist and are real, then they have to put forth the evidence in a way that can be reliably and repeatedly demonstrated by experimentation and close observation, and those things haven’t been done yet, either. So far, the only people who have attempted those proofs have been proven to be con artists, magicians, priests and other fakers – and that fakery can be demonstrated and proven to be false.
So the evidence in favor of the supernatural is scant to nonexistent, and those phenomena cannot be proven yet (if they ever can be) – even though they can never, ever be entirely disproven, either by any human faculty which we know of. Which still doesn’t mean that they don’t exist, only that they can’t be reliably demonstrated. And the fact that the only “evidence” that has been set out has been reliably disproven; so that’s the smart money bet.
More often than not, “voices in one’s head” are cognitive, emotional, hallucinatory or false memory artefacts of one’s own mind – which can sometimes but not always be demonstrated to have a natural / physical cause.