Have you tried setting your hair on fire?

The Cartoon Dog stood vacantly in the center of the stage, staring listlessly out into the amphitheatre. "They're not listening to me." He shrugged diffidently and slapped his paws on his haunches.

The Stoic Cat entered from Stage Left, shaking his head dismissively. "Have you tried setting your hair on fire?"

The Cartoon Dog turned around. "They don't pay any attention to me. It's like I'm not even here."

The Stoic Cat folded its arms and looked down sadly. "Take a look around. The theatre is empty. Aside from the fact that you are a non-existent cartoon character, the 'they' are the ones not here."

The Cartoon Dog wiped tears from its eyes and searched the rafters for a moment. "What do you do, to get their attention?"

The Stoic Cat walked across the stage, behind the curtains at Stage Right. "Come on back to the Philosophy Department with me. Let's smack your head on a desk to prove that the desk exists. The headache might help you feel better."