The burden of proof lies on whoever wants to convince someone else of something. in this case the guy that wants to convince people it likely is not real.
> "The human brain is mutable, the human "soul" is a concept thats not proven yet and likely isn't real."
The soul is "a concept that's not proven yet." It's unproven because there's no convincing evidence for the proposition. By definition, in the absence of convincing evidence, the null hypothesis of any proposition is presumed to be more likely. The presumed likelihood of the null hypothesis is not a positive assertion which creates a burden of proof. It's the presumed default state of all possible propositions - even those yet to be imagined.
