An essential element of Wuthering Heights is the exploration and extension of the meaning of romance. By contrasting the passionate, natural love of Catherine and Heathcliff with the socially constructed forms of courtship and marriage, Emily Brontë makes an argument in favor of individual choice. Catherine and Heathcliff both assert that they know the other as themselves, that they are an integral part of each other, and that one’s death will diminish the other immeasurably. This communion, however, is doomed to failure while they live because of social constraints. Heathcliff’s unknown parentage, his poverty, and his lack of education make him an unsuitable partner for a gentlewoman, no matter how liberated her expressions of independence. Brontë suggests the possibility of reunion after death when local residents believe they see the ghosts of Heathcliff and Catherine together, but this notion is explicitly denied by Lockwood’s last assertion in the novel, that the dead slumber quietly.
The profound influence of Romantic poetry on Brontë’s literary imagination is evident in her development of Heathcliff as a Byronic hero. This characterization contributes to the impossibility of any happy union of Catherine and Heathcliff while they live. Heathcliff looms larger than life, subject to violent extremes of emotion, amenable to neither education nor nurturing. Like Frankenstein’s monster, he craves love and considers revenge the only fit justice when he is rejected by others. Catherine, self-involved and prone to emotional storms, has just enough sense of self-preservation to recognize Heathcliff’s faults, including his amorality. Choosing to marry Edgar Linton is to choose psychic fragmentation and separation from her other self, but she sees no way to reconcile her psychological need for wholeness with the physical support and emotional stability that she requires. Unable to earn a living, dependent on a brother who is squandering the family fortune, she is impelled to accept the social privileges and luxuries that Edgar offers.
Yet conventional forms of romance provide no clear guide to successful marriage either; both Edgar and his sister, Isabella, suffer by acting on stereotypical notions of love. Edgar does not know Catherine in any true sense, and his attempts to control her force her subversive self-destruction. Isabella, fascinated by the Byronic qualities with which Heathcliff is so richly endowed, believes that she really loves him and becomes a willing victim in his scheme of revenge. What remains is a paradoxical statement about the nature and value of love and a question about whether any love can transcend social and natural barriers.
Another theme that Brontë examines is the effect of abuse and brutality on human nature. The novel contains minimal examples of nurturing, and most instruction to children is of the negative kind that Joseph provides with his lectures threatening damnation. Children demonstrably suffer from a lack of love from their parents, whose attention alternates between total neglect and physical threats. The novel is full of violence, exemplified by the dreams that Lockwood has when he stays in Wuthering Heights. After being weakened by a nosebleed which occurs when Heathcliff’s dogs attack him, Lockwood spends the night in Catherine Earnshaw’s old room. He dreams first of being accused of an unpardonable sin and being beaten by a congregation in church, then of a small girl, presumably Catherine, who is trying to enter the chamber’s window. Terrified, he rubs her wrist back and forth on a broken windowpane until he is covered in blood. These dreams anticipate further violence: Hindley’s drunken assaults on his son and animals, Catherine’s bloody capture by the Lintons’ bulldog, Edgar’s blow to Heathcliff’s neck, and Heathcliff’s mad head-banging when he learns of Catherine’s death. Heathcliff never recovers from the neglect and abuse that he has experienced as a child; all that motivates him in adulthood is revenge and a philosophy that the weak deserve to be crushed. Hareton presents the possibility that degraded character can be redeemed and improved through the twin forces of education and love, yet this argument seems little more than a way of acknowledging the popular cultural stereotype and lacks the conviction that Brontë reveals when she focuses on the negative effects of brutality.
A third significant theme of Wuthering Heights is the power of the natural setting. Emily Brontë loved the wildness of the moors and incorporated much of her affection into her novel. Catherine and Heathcliff are most at one with each other when they are outdoors. The freedom that they experience is profound; not only have they escaped Hindley’s anger, but they are free from social restraints and expectations as well. When Catherine’s mind wanders before her death, she insists on opening the windows to breathe the wind off the moors, and she believes herself to be under Penistone Crag with Heathcliff. Her fondest memories are of the times on the moors; the enclosed environment of Thrushcross Grange seems a petty prison. In contrast to Catherine and Heathcliff, other characters prefer the indoors and crave the protection that the houses afford. Lockwood is dependent on the comforts of home and hearth, and the Lintons are portrayed as weaklings because of their upbringing in a sheltered setting. This method of delineating character by identifying with nature is another aspect of Emily Brontë’s inheritance from the Romantic poets.