The Power of the Presupposition

Me: You're a ghost!

Bill: No, I'm not!

Me: Yes, you are, my friend! You're a ghost! I'm sure of it!

Bill: What are you talking about?! I'm not a ghost!

Me: Well, I know you're a ghost. It's just so obvious. And you'll never convince me otherwise.

Bill: Hey, that's ridiculous. I'm not a ghost. I can't walk through walls. See? *bump*

Me: Well, then. I see ghosts have the option of feigning materiality or not.

Bill: Sigh. Don't be this way. Everybody knows that ghosts are always and only immaterial.

Me: But you just proved otherwise!

Bill: Sigh. I'm not a ghost. Look, if you cut me, I bleed.

Me: Wow! So ghosts bleed? I never knew ghosts could bleed! Ghosts bleed...

Bill: No, no, no! If I bleed, I'm not a ghost!

Me: Says the only ghost I know. Sheesh, you think I'm that easy to fool?

Bill: How can I ever get this across to you? What can I do to prove this to you? I'm not a ghost!

Me: But you are, you are, you are! I know you are!

Bill: Look! If you stab me with a knife or shoot me with a gun and leave me there bleeding, I will die!

Me: Oh.

Bill: Yes! You see now?

Me: Hmm... so ghosts... can die?! This is a puzzling one.

Bill: Argh!

Me: So ghosts can die. Hmm. If you, being a ghost, would die, then I wonder what would happen to you? Would you turn into some kind of uber-ghost, or would you go into some second-level, ghostly dream state? Like something out of the movie, Inception? Man, that movie messed my brain up.

Bill: I'M NOT A GHOST!!!

Me: So it seems evident...

Bill: YES?

Me: It seems evident that ghosts can lie.