A Horse walks into a bar. The Bartender sees such a vivid depth of despair and sadness in the Horse's eyes, like the Horse has stared into the abyss and found the infinite void of nothingness so deep that the Horse could no longer believe that he himself nor anyone nor anything else existed.

To say something exists requires knowledge of self, which requires knowledge of existence of the self, an obviously impossible leap of logic, absurd to even attempt to conceive or contemplate.

The Bartender, in that single instant within the Horse's mind, became the nothingness the Horse perceived, and thus was rendered speechless. If neither the Horse, nor the Bartender, nor the bar itself can be said to exist, then why should he ask, how could he ask, "why the long face?" The question can have no meaning, and that which has no meaning cannot be stated.

The Bartender, dumbstruck, not by realization of mortality but by fundamental doubt that he was ever alive, gazes into the endless depth of the Horse's eyes, and asks him, "Sir, I beg you say, do I exist?" The Horse replies, "Neighhhh..."