All through the play Willy instills his "American Dream- on Biff, who believes his father and wants to be accepted by him, until one day Biff walks in on his father with another woman. From there Biff and Willy fight whenever they are together. Biff sets out west he wanders from place to place. From the time Biff was young he had a kleptomaniac problem. Blinded by his own nave views Willy does not address this problem. This unattended quality leads to Biff spending time in jail while he was out west. The time of their life the play takes place Biff still tries to please his father. Finally at the end Biff no longer accepts the illusions that his family and especially his father have lived in. In a final conflict with Willy, Biff calls him out on all of his lies and false ideals. Biff tells Willy that he realizes that he himself has been a Bum and its not Willy's fault and he finally realized the true meaning of success. This view of success Biff has come to realize is probably Miller's own thought on what success in America should be based on. This view is of inner happiness, your family, your true dreams and the use of your true skills in the workplace is the true meaning of success.
Ashamed to be stuck in Brooklyn with a low-paying job, Willy yearns for his brother Ben's happy-go-lucky lifestyle. Ben represents more of a dream of success rather than an ideology. In the play it says Ben went looking for their father in Alaska but made it to Africa and in the jungle he stumbled into some diamond mines. However this takes on two meanings in the book. One meaning is nothing more than it seems, Ben got lucky and became rich. The other meaning however is referenced several times in the book. Both Ben and Willy use the jungle as a metaphor for life and diamonds as success. An example of this is when Ben tells Willy .
Ben. You must go into the jungle and fetch a diamond out. (2:5).
or near the end when Willy mentions that the woods are burning but he can't drive.