From the 2002 version of Solaris, a very well done piece of work by Soderbergh.
Gibarian: You think you’re dreaming me.
Chris Kelvin: You’re not Gibarian.
Gibarian: No? Who am I then?
Chris Kelvin: A puppet.
Gibarian: And you’re not? Or maybe you’re my puppet. But like all puppets you think you’re actually human. It’s the puppets dream, being normal.
(nicked from this site)