What are the universal truths regarding human conditions in The Crucible and what approach does Miller use to develop that theme

Arthur Miller develops two related universal truths, or themes, in this play through the morally ambiguous character of John Proctor. First, through Proctor's development, we see that redemption is always possible. Early in the play, we learn that Proctor has broken one of the Ten Commandments and committed adultery with Abigail Williams. His sin has dramatically affected his self-esteem, and he now lives "with [a] deep hatred of himself." Proctor thinks of his wife as good and pure while he is soiled and sinful. However, by the end of the play, after he's begun and then stopped himself from confessing a lie to save his life, Proctor develops a more positive self-image. During the confession, he says that he is "not worth the dust on the feet of them that hang," but once he rescinds his confession, he tells his judges, "You have made your magic now, for now I do think I see some shred of goodness in John Proctor." In refusing to add a new sin on top of the other sins he's committed, Proctor is able to redeem himself, and he can think of himself as good once again.
Second, through Proctor's character, we see that one's self-respect is more important than anything else. For a time, in Act Four, it seems that Proctor is going to confess a lie. However, when he is asked to name the names of other witches, he refuses. When he is told he must sign the confession, which is to be nailed to the church door, he thinks twice about continuing with the lie. He cries out, "I have given you my soul; leave me my name!" While Proctor signs himself to lies, he cannot feel any self-respect; when he finally tears the confession up, he regains that self-respect despite the fact that it means his life is forfeit. Ultimately, he knows that his self-respect is worth more than his reputation in the town, the judgment of the court, and even his life.
By developing the moral ambiguity of John Proctor, Miller illuminates these two related themes.