Love
Underneath nearly every scene and decision in Scythe is the theme of love: whom do we love, and how? What do we love, and why? What will we give up to protect what or whom we love?
Rowan and Citra feel romantic (or at least very intimate) love for each other, and Scythes Faraday and Curie were lovers once, despite this being a violation of the scythe code. Both couples sublimate their love in favor of the larger picture: Faraday and Curie remain friends and allies, many decades after their affair, working together to improve the Scythedom; Rowan and Citra consider each other from afar, until Citra makes it possible for him to escape—even after his escape, they can't contact each other as Scythe Anastasia and Scythe Lucifer.
Citra experiences familial love, though her parents essentially ask her to become a scythe so that her younger brother, Ben, will have immunity from gleaning. She is deeply hurt by killing Ben in her final apprentice test, because she knows that neither of them will ever forget that pain, even though he'll survive. There is familial love between High Blade Xenocrates and Esme, as Xenocrates is blackmailed into changing the future of the Scythehood (and also into embarrassing himself) to save her life.
The novel also explores broader examples of love: the Thunderhead's "love" of humanity's interests; Scythe Goddard's love of murder; Scythe Faraday's love of order and his compassion for humanity; Scythe Curie's love of cooking, and her use of it to comfort the families of those she gleans.
Though Scythe generally avoids falling into the genre of teen romance, love underpins every moment, providing a powerful motivating factor in a narrative with many conflicting interests.
Death
Scythe obviously explores a theme of death, as people die both temporarily and permanently throughout the novel. Some, like Tyger, die intentionally and often, for attention or the experience; others, like Rhonda Flowers, die for the perks of being revived. Some people die for money, like the 2,000+ people Rowan kills at Scythe Goddard's estate. There is a large cultural difference between death and gleaning, and gleaning is rare but immensely frightening—Scythe Curie explains that in 5,000 years of life, a person has only a 50% chance of being gleaned, and Rowan reflects that before Kohl Whitlock, the only gleanings he'd heard about were rumors.
Scythes choose their manner of gleaning (within the rules of their conclave), allowing Scythe to explore the "correct" way to kill, die, and mourn. Even the two scythes presented as good, Scythe Faraday and Scythe Curie, differ in this: Scythe Faraday gleans differently every time, and always based on statistical profiling; Scythe Curie always gleans with stabbing through the heart, and she gleans strangers by observing how "stagnated" they look. Scythe Faraday gives the people he gleans the opportunity to write a letter to their loved ones; Scythe Curie doesn't give the people she gleans enough time to even notice what's happening. Scythe Faraday attends their funerals to pay respects; Scythe Curie cooks dinner for the victim's family, encourages them to share the victim's life with her, and offers to let them kill her.
Whether one approacher is better than the other is up for debate, and in fact this question is debated in the novel, as the bejeweling committee balances compassion and efficiency in Citra's final apprentice test. The novel does pass unequivocal judgment on what is not a good way to kill, which includes murder (killing for the joy of killing), gluttony (indulgence for no practical reason, especially in violence), and killing with fire—or at least killing innocents with fire, looking at Scythe Lucifer. Though the Scythedom is divided on using fire to glean at the end of the novel, the novel as a whole clearly is not, as Citra observes that "common sense finally prevailed" when gleaning by fire is banned; in a Reddit AMA, Shusterman himself confirms that, in his view, anyone who gleans with a flamethrower deserves to die.
Coming of age
Behind the death, violence, and ethical dilemmas of Scythe, the novel is a coming-of-age story for Citra and Rowan. Each protagonist is confronted with challenges uniquely difficult for them, forcing them to change across the narrative. Rowan, who comes from a neglectful, lonely background, is tempted by the overwhelming excess of Scythe Goddard's lifestyle, as well as the continuous validation Scythe Goddard gives him. His gift for empathy is used as a tool against him, as he's forced to kill again and again, as well as not kill people who are begging him to kill them so they can be paid. He ventures into ideological "adulthood" with his beheading of Scythe Goddard, signifying his choice of independence, though he can never undo what he was forced to do at Scythe Goddard's estate—or the joy and validation he got out of it.
Citra's coming of age is more internal, less trial-by-(literal)-fire. An angry young woman with very little patience, Citra has almost no impulse control at the beginning of Scythe, and she sees things generally in a black-and-white framework of Yes and No. (For example, finding purpose as a scythe is a firm No.) Through training and making more obvious "mistakes"—touching Scythe Faraday's ring, yelling at Scythe Curie in public—Citra grows bit by bit, until she is receptive to months of ethics-focused training in Playa Pintada with Scythe Faraday, something she'd have hated six months before. By the time Citra becomes Scythe Anastasia, she has devoted herself to a life of pondering and compassion...mostly. Though Citra at first seems much less empathetic than Rowan, by the end of Scythe she acts in the best interest of the Scythehood as a whole, even when that means breaking the Scythehood's black-and-white framework.
Moral living / excess
Just as Scythe explores a theme of proper death, it also explores a theme of proper life. The day-to-day activities of scythes are, by necessity, strange, and old-guard scythes generally live ascetic, disciplined lives. An argument could be made that this means Scythe as a whole promotes this lifestyle as an ideal. However, being a scythe is unique and (hopefully) not identical to the reader's experience; perhaps this indicates that a moral life for the reader is a thoughtful one, not one as strictly disciplined as, say, Scythe Faraday's.
The novel's moral musings on proper living come mostly from its depictions of living poorly. Excess is only presented positively if it is an extreme outlier (for example, Scythe Faraday filling his plate at conclave). Scythe Goddard is the most obvious example of this: he kills opulently, dresses opulently, parties opulently, and performs cruelty as richly and often as he can. Scythe Goddard is also a clear villain. Scythes Chomsky and Rand follow his example; Scythe Volta's redemptive qualities are only noticed by Rowan after Volta doesn't indulge, not eating at dinner after a mass gleaning. High Blade Xenocrates's tastes are a complex mix of excessive and spartan, but his large figure and his illegitimate daughter indicate a tendency toward indulgence—and this indulgence is how Scythe Goddard blackmails him. Even Esme indulging in a secret slice of pizza has negative consequences, as the entire food court is gleaned and she's taken as Scythe Goddard's (pampered) captive.
Scythe Curie muses that every scythe must have a "guilty pleasure," like her cooking; perhaps the key to moral living is "guilt," implying both intellectual and emotional engagement with one's choices.
Compassion versus efficiency
The Scythedom is split about their future and ethos, a conflict which becomes more obvious to Rowan and Citra as they're thrust into the middle of the conflict. The Scythedom's split centers around a theme of the novel: compassion versus efficiency.
The theme of compassion versus efficiency is most overtly explored in gleaning practices. Should one glean with compassion, or glean efficiently? And what does that mean? Scythe Faraday's unique, well-prepared gleanings are compassionate, allowing the gleaned to come to terms with their death and say a final goodbye. Scythe Curie's manner of gleaning, on the other hand, is very efficient. She shows almost no compassion for the gleaned during the act, but she only gleans people she believes are "ready," and she dedicates the rest of her time to compassion for the gleaned's loved ones. Scythe Goddard gleans without compassion at all, and it's arguable whether mass gleanings are efficient—though they might be, efficiency is not his motivating factor. The powerful weapon introduced in Scythe, Touch of Quietude, is terrifically efficient. It kills immediately and painlessly, which one could argue is more humane than the other represented methods of gleaning.
This theme is the hinge of the novel's "old guard" and "new order." Citra and Rowan represent different sides of this thematic coin, as illustrated by their final apprentice test. Citra spends a long time helping Ben feel comfortable, while Rowan kills his mother with a quick shot through the head. The bejeweling committee is split between their techniques, and so is the Scythedom. Though the tension between compassion and efficiency is not resolved in Scythe, most main characters tend toward compassion and the old guard.
Appreciating art
Appreciating art is another dominant theme in the novel. Many of Shusterman's works feature allusions to great works of art, in a variety of forms—literature, painting, legend, and so on. Rowan is so moved by the Age of Mortality artwork that he decides to become a scythe, completely altering his life to pursue that feeling. Scythe Curie chooses to live in Falling Water, a house designed by the famous architect Frank Lloyd Wright, just to preserve the architecture, since she knows that if a scythe lives there people will care for it as it deserves. Scythe Curie also loves cooking, creating both comfort food and elaborate meals, using them to facilitate conversations with Citra as well as comfort grieving families. Scythe Faraday exposes Rowan and Citra to different artworks (Verdi's opera, as well as multiple paintings) the same way he exposes them to ethics and weapons—he expects them to engage, observe, and draw their own conclusions.
Making your own decisions
Making your own decisions is a central theme of Scythe, in both its content and its form. The entire narrative is about choices: Old guard or new order? Compassion or efficiency? Soar or scurry? Rowan and Citra's character arcs both lead toward independent decision-making: Citra is encouraged to find her own method of gleaning, as well as her own philosophy behind it; Rowan decides to become not an eagle or a mouse, but rather an executioner of eagles. They're helped along the way by people with their own agendas, but many, like Scythe Faraday and Scythe Curie, strive to give Rowan and Citra the tools to make their own decisions, choosing their own paths.
The form of Scythe develops this theme as well, since one of Shusterman's primary prose techniques is presenting foils. By offering contrasting characters and outlooks, rarely specifying which one is "better," Shusterman allows the reader to make their own decisions about what is right or wrong. Just as Citra and Rowan make their own decisions, the reader can choose their own alignment from among many options, many (arguably all) of which are imperfect.
