“Who’s there?”

As is frequently the case with Shakespeare, the first line addresses one of the play’s central themes: Questions of identity and selfhood will become critically important to the story. In particular, Hamlet will address the difficulty of establishing who one “really” is.

“Seems, madam? Nay, it is. I know not ‘seems.’”

In one of Hamlet’s first lines, he lays out an important tension between what is real and what only appears to be real. By insisting that his outward shows of mourning truly reflect his inner grief—with an implied criticism of his mother’s speedy recovery from her husband’s death—Hamlet observes that it’s very easy to pretend to feel something you don’t. 

“From this time / Be something scanter of your maiden presence [...] For Lord Hamlet, / Believe so much in him that he is young, / And with a larger tether may he walk / Than may be given you. In few, Ophelia, / Do not believe his vows, for they are brokers”

By discouraging Ophelia from taking Hamlet’s professions of love too seriously, Polonius lays out a number of the play’s dilemmas, and foreshadows later tragedy. Words, Polonius says, are not worth much, and women, in particular, must beware the cajoling words of men. Hamlet is much freer than Ophelia; he can do what he likes, while her safety and well-being in society depend on a public perception of sexual purity. Polonius’s warning is both stern and truthful.