T-Rex: Ah, solipsism. The belief that only one's self exists! Everything and everyone else are just a projection of my imagination. I made them up! Who invented all the arts and sciences?
T-Rex: Why, apparently, it's me - T-Rex!
Dromiceiomimus: Okay, but if this is the case, why do you imagine a world for yourself in which people's ice cream cones can fall in the dirt?
T-Rex: Probably I just want to make things more interesting!
Dromiceiomimus: And I guess all the pain and death in the world is also just to make things more interesting?
T-Rex: That makes me sound pretty messed up, but yeah! I guess!
Utahraptor: But you do admit you don't have control over the entire universe, right?
T-Rex: I can't make you dance, that's true!
Utahraptor: Right! So part of your mind you can't control (your unconscious) must be at work there. But since you can't control it, it's effectively external, right? So the rest of the universe is still external to you! You haven't gained anything by imagining it's all in your head.
T-Rex: Dude, I gain the knowledge that if I die, the rest of the universe dies with me. Woo hoo!
T-Rex: (This makes me super important!)