- Why didn't Biff reveal Willy's affair in the final argument? He's so much affronted about self deception, yet he never reveals why he and Willy are at conflict with each other with anyone else. It's a tad hypocritical.
- It could be possible that everyone knew already. One of the impressions I got from reading the play was that even his wife knew-or at least speculated. Additionally, Miller may have not wanted to stretch out the climax of the play by bringing up a point the audience already knows-the point of that argument is Biff is shattering his father's beliefs, bringing up the affair would have been redundant. I can only speculate, though, these are just some theories that might answer the headscratcher.
- Well, it seems that bringing up the affair would be part of the "We never told the truth in this house" part.
- It's entirely likely he was trying to spare Linda's feelings by withholding the truth. That's not the same thing as lying, or at the very least, not the same kind of self-aggrandizing and delusion that the Lomans typically engage in.
- It's not really hypocritical in the context of that argument, because Biff isn't deceiving himself. At that point Biff isn't lying to himself about why he's angry and upset with his father; the affair is part of it, certainly, but that's just the catalyst for his disillusionment with Willy, it's not the only or even main reason. His overall point isn't that Willy's an unfaithful liar, it's that Willy (and to a lesser extent the rest of the family) lies to himself and retreats from the world in fantasies that he's never going to achieve rather than face the truth about who and what he is. Biff doesn't want to embarrass and humiliate his father or destroy his mother and father's marriage, he just wants his father to face reality. You said yourself; Biff's point is about Willy's self-deception, not about the ways he deceives or is unfaithful to others. Besides which, Biff's angry at his father, not his mother; he doesn't want to cause his mother pain, which bringing up the affair would almost certainly do, so he's discrete about it.
Headscratchers / Death of a Salesman