My observation was meant to be more rueful than determinative.
I disagree that you can always prove something to someone via logic and observation. Remember that great and very true line about none so blind as those who WILL not see none so deaf as those who WILL not here.
Never forget there were folks who refused to look through Galileo's telescope.
As to having to prove everything that you know, that would take a lot of time and the sun's gonna come up tomorrow and find you doing -