We are playing a game, and the game runs like this. The only thing you really know is what you can put into words. Let's suppose I love some girl, RAPTUROUSLY. And somebody says to me, "do you really love her?" Well, how am I going to prove this? "Let's say you like poetry. Tell us all how much you love her and then we'll believe you." So if I'm an artist and can put this into words and can convince everybody that I've written the most ecstatic love letter ever written.
Then they'll say "Alright, ok we admit it you really do love her. "
But supposing you're not very articulate are we going to tell you you don't love her?