What is Willy's philosophy in "Death of a Salesman"?

Miller creates the character of Willy as the embodiment of the failure within the American Dream.  Willy is presented as a prototypical American male of the post World War II era who was taught that if he works hard, plays by the rules, and believes in the authenticity of his dreams, success will be evident.  The reality is that this is not the case in that there are obstacles that inhibit the realization of a dream where monetary and financial success represent the ultimate payoff. Willy's philosophy is to believe in his dreams and within this notion of "big dreams," he will succeed.  The reality is far different because of the matrix of inhibitions that prevent this dream from becoming a reality.  Willy's philosophy of dreams involve "making it big," which is a strictly economic notion of the good.  This challenges him to find success in a vision where the finality of money determines success or failure.   The constant denial of the realization of this conception of dreams compel him to commit suicide for a monetary payoff.  In this philosophy of life, one's value is directly tied to money.  Miller creates this in a deliberate manner in his desire to provide a more complex notion of the "American Dream" philosophy that enveloped so much of American society.