In his novel, Lawrence delves into the theme of free will, examining the extent to which his characters' environments shape their choices. He illustrates this through vivid imagery. For example, when Paul begins looking for employment through newspaper ads, the narrator observes, “Already he was a prisoner of industrialism . . . He was being taken into bondage. His freedom in the beloved home valley was going now.” The influence of the modern industrial world, especially the mining culture's effect on the Morel family, molds the characters' ambitions. Mrs. Morel, who sees herself as morally superior to the miners, is disgusted by the impact of mining on her husband and guides her children away from that path. She finds jobs for both Paul and William to ensure they have better futures than their father. The sons struggle to make independent decisions, driven by a desire to satisfy their mother to the point of neglecting their own happiness and needs. Both find it challenging to build emotionally healthy relationships with women and grapple with aligning their desires with their mother's expectations. Another character, Miriam Leivers, also suppresses her own will to accommodate someone else's needs, consenting to sleep with Paul to please him despite not having strong sexual feelings for him.

By candidly depicting human sexuality in his novel, Lawrence defied the moral expectations of his era and literary genre, earning a controversial reputation. At least one publisher turned down Sons and Lovers because of its sexual themes. Lawrence's ideas on human behavior revolved around what he called “blood consciousness,” which he contrasted with “mental and nerve consciousness.” He argued that “blood consciousness” was the source of willpower, inherited through the mother. This concept is reflected in Paul and William's strong bond with their mother and in Paul's determination and emotional depth, qualities he shares with her.

Lawrence claimed that modern society was overly dominated by mental consciousness, leaving it largely disconnected from its own desires. He expanded on these ideas in Psychoanalysis and the Unconscious (1921) and Fantasia of the Unconscious (1922), where he also shared his perspectives on male-female relationships. His provocative novel, Lady Chatterley's Lover (1928), was accused of obscenity and pornography, resulting in legal battles against its publishers. Additionally, Lawrence defied societal conventions in his personal life by eloping with Frieda von Richthofen Weekley, who was married to a University of Nottingham professor.

Some critics have argued that Paul’s relationship with his mother illustrates Freud’s Oedipus complex, suggesting that both Paul and Lawrence were sexually conflicted and repressed due to their profound emotional ties to their mothers.

Lawrence’s characters underscore the class contradictions that are inherent in modern industrial society. Capitalism generates conflicts not only between different social classes but also among individuals within the same class. Lawrence delves into this theme by depicting tensions among various groups and characters. For example, William ambitiously climbs the social ladder, only to feel increasingly estranged from his family as he rises. His girlfriend, Lily, a snobbish and pretentious Londoner, looks down on the working class and treats the Morels with disdain, believing them to be “clownish” and lacking sophistication. Even Mrs. Morel, who was once a teacher, holds contempt for her husband’s work and is repulsed by his miner friends, whom she considers inferior. The most glaring class disparity is illustrated in the dynamic between Thomas Jordan, the capitalist factory owner, and his employees, whom he patronizes and frequently argues with.

Lawrence frequently delves into the interactions between men and women, emphasizing the conflict between masculine and feminine principles. This theme of duality is a key element in his writing. In