What was Big Willy Shakes going for?
So we get the literal meaning of all this. Be true to yourself. Don't borrow money to buy things you cannot afford. Don't pretend to be something you're not. Quoted out of context, it all of sounds like good advice. "Neither a borrower or a lender be"? Sure, we can get behind that. "To thine own self be true"? Yep, that also sounds like pretty solid advice. Profound, even.
But given that Polonius is the one telling us (or Laertes) these little tidbits of wisdom, are we supposed to take it seriously? Is Shakespeare actually making fun of this cheery, cliché, How to Win Friends and Influence People type of early self-help? (You just know Polonius would have written a self-help book filled with this stuff.)
As comical and ridiculous as Polonius is, his elaborate attempts to keep tabs on Laertes and Ophelia remind us that fathers can't always be trusted to care for their children. This is especially true for dear old Polonius who pays Reynaldo to spread rumors about Laertes so that Laertes will confide in Reynaldo, and then Reynaldo can report back to Polonius (2.1.4). Scheme, much, Polonius?
And Polonius doesn't stop there. He is also all-too willing to use his daughter to get in good with the king —with disastrous consequences. His manipulative tactics leave Ophelia open to Hamlet's abuse and are probably partly to blame for Ophelia's tragic end.
So we ask again: are we supposed to take his advice seriously? Well, we'll leave that one to you, Shmoopers. We don't have all the answers. But we do know that Shakespeare is totally making fun of Polonius by giving him tone-deaf advice, a nasty habit of spying on pretty much everyone, and just about the worst sucking up to the king we've ever seen. But that doesn't change the fact that his advice to his son about not living outside your means makes a whole lot of sense.
This was a common idea around the time Shakespeare was writing because it was passed down from the Greeks. We can see why his society was interested in it. There were actually rules (called "Sumptuary Laws") that governed choices in dress. In fact, the fabric, color, and style of costume were all symbols meant to distinguish and separate gender and class identities. It was a big no-no to wear something inappropriate to your social rank. That goes for wannabes just like the ones Polonius is hating on here.
What's more is that costumes are a big deal in Hamlet. When the Prince wears an "inky cloak" at the beginning of the play, his mom freaks out because he's in mourning for his dead father—but he's the only one in court still wearing black. Now that Claudius is king, the happy couple wants everyone to forget about Old Hamlet and dress in bright colors again. So, Hamlet's black attire sets him apart from everyone else —just like his grief makes him an outsider in the cheerful court.
But don't tell Hamlet that his clothes reflect his grief —he might jump down your throat, and tell you that his clothes "denote me truly"(1.2.4). In other words, Hamlet objects to the idea that any outward signs (dress, behavior, etc.) can truly "denote" what he's feeling on the inside (which is rotten). Hamlet's "suits of solemn black," he says, can't even begin to express his grief and anguish.
So Hamlet tells us that his costume is important because it tells us something about who he is. Hmm…sounds like the exact same thing Polonius is saying, doesn't it? (Except with a dark and twisty anguish that only Hamlet can add.)