“I think to him they were all my sons. And I guess they were, I guess they were.” This is what Joe Keller says after discovering why his son, Larry, killed himself. Larry was angry and heart-broken to think of his father shipping airplane parts that were responsible for the deaths of his fellow airmen. Joe made the tragic choice to ship the parts because he wanted to preserve his company in order to provide for his family. He wanted to be able to support his family in the short run and also have someone to pass on to his sons in the long run. His statement is recognizing that ALL of humanity should be honored to the same level that he holds his biological sons. This recognition drives Joe to also commit suicide.
Arthur Miller uses this family tragedy to make a clear statement about war - about the economics of war and the decisions made during wartime that were unethical and inhumane. He also makes the point that one can't justify wrong decisions that impact the greater community because they are right for the individual.