thunderclap said:4.) When Vader tells the Emperor Luke is on Endor with the revels the Emperor says it's strange he hadn't sensed him. Yet a few lines later he tells Vader to go down and wait for Luke because he will go to him. He knows this because he'd foreseen it. It's always seemed like a contradiction to me. One of these lines needs to be removed.
To me, the contradiction is meant to show us that the Emporer isn't all-knowing, and that he's starting to make things up as he goes along.