In Shakespeare's Hamlet, what does Hamlet mean when he wonders "What is a man if his chief good and market of his time be but to sleep and feed?"
In Act IV, scene iv, of Shakespeare's Hamlet, the Prince of Denmark's main concern is the purpose of man, and how Hamlet fits into it.
Hamlet's speech that begins with, "What is a man if his chief good and market of his time be but to sleep and feed?" is speaking to the fact that if we are only on this earth to pass time and eat, we are no better than the animals. To what end, then, is man put on this earth? In it, Hamlet berates himself for not having done anything yet to avenge his father's murder.
Hamlet then compares himself to Young Fortinbras and his men. For a small piece of land, they are prepared to die. It is not for the land itself, but for the honor Fortinbras perceives to have been lost when his own father, Old Fortinbras, lost his land and his life battling with Old Hamlet. Fortinbras is often considered a foil for Hamlet, who is someone with a great many similarities: by comparison it would seem that Fortinbras is a more honorable man who has acted upon his sense of duty and honor, while Hamlet vacillates about killing Claudius while not doing so.
Hamlet, in this quote, is wondering what separates man from the beast: what is it that makes life on earth worthwhile? He, more than anyone, has more than enough reason to kill Claudius and he does not. Yet, for a much smaller concern over honor, here Fortinbras and two thousand men are ready to die for their honor. The land they fight for is not large enough to bury them if they are killed, and yet for honor, they will die. And if they are willing to do so for such a small prize—steeped in honor—Hamlet feels honor-bound to finally avenge his father's death as a point of his honor, so much more important than a tiny piece of land.
...to my shame I see the imminent death of twenty thousand men / That, for a fantasy and trick of fame, / Go to their graves like beds, fight for a plot / Whereon the numbers cannot try the cause, / Which is not tomb enough and continent / To hind the slain? O, from this time forth / My thoughts be bloody or nothing worth. (IV.iv.61-68)