What is the main theme of All My Sons?
The themes of this play might be said to revolve around ideas of honesty. Guilt and the admission of guilt, accusation, denial, and dishonest business practices are all central elements of Miller's play.
Keller denies his crime first and after later admitting to his practical responsibility he denies his moral responsibility.
Joe's decision to send defective parts is not merely a result of skewed values, it is a serious breach of ethics. Joe does not fully comprehend how serious a breach it is.
Joe Keller continues to deny his guilt even after he admits his crime.
"If my money's dirty there ain't a clean nickel in the United States. Who worked for nothin' in that war? … Did they ship a gun or a truck outa Detroit before they got their price?"
Keller only realizes at the play's conclusion the true extent of his guilt as he discovers that Larry died as a result of Keller's decision to sell the faulty airplane parts.
Across the whole play, the truth is in question, the past is dramatically present yet obscured (intentionally and by happenstance). Chris, Ann, and George each in turn attempt to get an honest telling of the story of what happened with the airplane parts. Keller, for his part, evades the truth and the telling of the truth for as long as he can.