Betrayal provokes revenge in this play: Brachiano, Flamineo and Vittoria betray Camillo and Isabella, and end up getting murdered by Lodovico and Gasparo. Even Zanche, who betrays Vittoria by deciding to rob her and leave with "Mulinassar" (Francisco), dies in the finale. Dante (the great Italian poet) thought that betrayal was the absolute worst sin—at least, with other, non-betraying kinds of murder you're not abusing anyone's trust, in addition to killing them. But betrayal strikes at the very heart of life—if you can't trust the people who are closest to you, then who can you trust? But everyone in The White Devil would be well advised to distrust everyone else—and, for the most part, that's what they do.
Betrayal is the worst crime or sin a person can commit, since it ruins the human relationships that form the basic network of life.
Eh, there are worse things than betrayal—what about genocide?
The families in The White Devil aren't exactly what you'd call models of domestic stability. Some family members genuinely care for each other—like Francisco, Isabella, and Giovanni—but others seem to be having a miserable time. Cornelia's children (at least, Flamineo and Vittoria) go against her wishes, plotting murder and adultery—and Flamineo murders her only good son, Marcello. And Vittoria's marriage to Camillo and Brachiano's marriage to Isabella are both terrible (considering they end in murder). But there's a hint that things could've been better—Flamineo seems to regret killing Marcello when he sees how distraught his mother is. By sticking with his familial affections, instead of just trying to upgrade his social status, maybe Flamineo could've been better, but we'll never really know.
The family is the basic unit of human life—a source of education, affection, and moral training. Without the family, people would devolve into self-centered barbarism.
Families screw people up worse than anything else.
Lust leads to violence in The White Devil. In committing and aiding acts of murder, Flamineo and Vittoria might be looking mainly to improve their social status, but Brachiano is all about lust. It seems that, aside from the desire for power, the desire for sex is the main force at play in Webster's world. Sex isn't typically a positive force in this play, either—it's destructive. Even Zanche's lust for "Mulinassar" ends up leading to her own destruction—she's executed along with Vittoria and Flamineo. Webster implies that there needs to be some sort of regulation of the sex drive for people to find peace and sleep easy at night, without dreaming of murder.
Sexual desire is an unstoppable destructive force—it needs to be curbed, restricted, and repressed to some degree.
Sexual desire is a potentially positive, creative force—you just need to channel it wisely.
Revenge is a reaction—you can't get revenge without someone else provoking you into pursuing it, obviously. In The White Devil, revenge takes the form of murder: it follows the same physical law, stating that every action needs to have an equal and opposite reaction. Since the action was murder (the murders of Camillo and Isabella), the reaction is going to be murder as well. But revenge never works out quite the way you planned—or it does if you're Francisco or the Cardinal, but not if you're Lodovico. In a way, Lodovico's own murders and crimes from the past end up coming back to get him—sure, he might have served justice by killing Flamineo and Vittoria, but he has too many sins on his head to escape poetic justice himself. He has nothing to look forward to but torture and death.
Revenge is always a bad idea—especially if you try to take the law into your own hands to get it.
Hey—sometimes revenge is a good idea, if the law fails to do its job or doesn't live up to its promises.
Flamineo is probably the most ambitious character in the play—though Vittoria likely isn't too far behind. He wants to increase his status in the world by aiding a "great man" like Brachiano, and is willing to use any means necessary to accomplish the task. But this doesn't end well, seeing as how he gets killed and all. This is probably because Flamineo's ambitions are entirely selfish—he's not ambitious to better the human condition or make improvements to Italy's political system or anything like that. Vittoria too, regrets that she's just the "ornament to a weak fortune" (since her husband isn't rich)—but doesn't have anything approaching a social conscience (or, arguably, a conscience in general).
"I have no spur
To prick the sides of my intent, but only
Vaulting ambition, which o'erleaps itself
And falls on th' other." — Macbeth, Macbeth (1.7.25-28).
"But this allows my varying of shapes;
Knaves do grow great by being great men's apes." — Flamineo, The White Devil (4.2)
The White Devil is chockfull of shocking and misogynistic statements about women, on the part of its male characters. These don't seem to represent Webster's views, however—since he has the audience's stand-in in the courtroom scene, The English Ambassador, comment on Monticelso's rant against "whores", by saying that he seems too bitter. Flamineo, the central villain, also has a lot of negative opinions on women—but, that's no surprise since he's a bad guy. On the other hand, Isabella—a basically good character—expresses her frustration with male-dominated society, as does her foil, Vittoria.
Women in Vittoria's time period were deprived of the ability to live freely and determine their own destinies.
Women in Vittoria's time were able to exercise power in different ways behind the scenes, allowing them make a significant contribution in the course of events (if not to the same degree as men).
Death becomes increasingly important as the play goes on, and the main characters are forced to confront their mortality. Flamineo and Brachiano seem to have a pretty bleak attitude towards death: they don't expect to go to heaven, and nothingness is the most they have to hope for—although hell is really their most likely destination. When confronting death, Vittoria is mainly confused—she has no idea where her soul is going and feels like it's lost in a "black storm." We never see a really hopeful depiction of death in the play—the closest is when Giovanni and Francisco discuss mortality, and Francisco tells Giovanni that the dead will rise someday, when God wants them too… but until then they sleep (3.2).
Prepare for death, because you never know when it might happen.
Don't prepare for death, because you'll die whether you've prepared for it or not.
Power is pretty closely related to ambition, because what are people ambitious usually about? That's right: power. Even if the ambition is focused on money—like how Vittoria wishes she was the "ornament" of a larger fortune—that's still the same, since money is really a form of power: crystallized power you can hold in your hand. Everyone in this play is scheming for power. Even the Cardinal manages to become pope, and, given his corrupt proclivities, we can assume this isn't just because he prayed really hard. Flamineo might be the most intensely power-focused, but Brachiano and even Francisco understand how to protect and defend power.
Absolute power corrupts absolutely.
Actually, if you train and discipline yourself properly, you can handle absolute power—just like some noble emperors did (consider Augustus, Akbar, Queen Elizabeth, and others, generally viewed as good rulers).
Webster's characters express some pretty dark philosophies in The White Devil. No one seems to discuss Christianity in any meaningful way (though Cornelia seems sort of Christian). Instead, older Greek and Roman philosophies or hard-toothed Renaissance power politics are mainly where these guys look to find a way of life. Machiavelli, who is mentioned once in the play (5.3), was an Italian philosopher famed for giving advice to nobles on how to maintain power at all costs, and Flamineo and Brachiano seem to have taken his advice to heart. The pessimistic, things-are-always-truest-at-their-bleakest, viewpoint seems to be very much present in play as well (especially with Flamineo). Additionally, there's Stoicism, characterized by a belief in mental and emotional toughness and in virtue as the key to life. Francisco expresses some Stoic ideas.
"You have power over your mind – not outside events. Realize this, and you will find strength." – Marcus Aurelius, Roman Emperor and Stoic Philosopher
"Men are so simple and so much inclined to obey immediate needs that a deceiver will never lack victims for his deceptions." –Machiavelli