I am reading Hamlet; Act 2 Scene 2 contains the following exchange:
Hamlet: O God, I could be bounded in a nutshell and count myself a
king of infinite space, were it not that I have bad dreams.
Guildenstern: Which dreams, indeed, are ambition; for the very substance of the ambitious is merely the shadow of a dream.
What is the meaning of
Which dreams, indeed, are ambition
What does the "which" refer to? The previous dreams? I understand it means "dreams are a sign of ambition". How does this follow grammatically?