How do you demonstrate the color blue to the color blind? How would you that? How can you get them to appreciate the color blue as you or I do?Well the proof would be in demonstrating an ability that others don't have in their own understandable terms but as you say it doesn't matter.
How does a schizo convince you or I that he speaks to God while riding the bus?
And, another thing, do you sit closer or further away on that bus from anyone that says i'm speaking to God now?