Who is Caliban?
I think this question is intentionally fascinating. We may be tempted to think that, for Shakespeare, Caliban is just a savage. But anyone who has read Hamlet or Othello knows that none of Shakespeare's characters are intentionally simple. So what is Caliban's complexity?
Let's look back on Hamlet's famous statement, "What a piece of work is a man!" Like most of Shakespeare's most striking lines, this one is usually taken out of context. Hamlet speaks this line, and the ones that follow, with a definite tone of uncertainty and possibly sarcasm. The praise is written like a rote prayer without heartfelt meaning. Shakespeare's concept of man, we see, isn't as clear cut as good and evil, black and white. If there are any doubts in this regard, all we need to do is consult Othello.
So is Caliban just a black savage with no redeeming qualities? You could argue that, but it would be an uphill battle. It's more likely that Caliban represents a side of man that most people in Shakespeare's time weren't comfortable speaking about; thus the relegation to a native creature, a seemingly unsympathetic fish-man whose only desire is to betray Prospero. He is uncultured, angry, and lustful. A piece of work, indeed.
I'm convinced that Shakespeare's "What a piece of work is man!" deserves to be read with a structural question mark. All of his best characters spring from the page wielding a difficult balance of darkness and light. And if any character in The Tempest begs our study in this context, Caliban does.