Class Conflict
John Barton's focus on the disparity of wealth permeates every page of Mary Barton. Barton's character is at the core of Gaskell's advocacy for communication between classes. The author believed that class struggles stemmed from misunderstanding and poor communication. John Barton murders Harry Carson to send a message of violent rebellion to the mill-owners. However, Gaskell believed that violence would not solve this issue; only a shared human experience had the power to make men understand each other. In this way, John Barton is a cautionary character, an example of what happens when communication goes awry.
Gender and Sexuality
Victorian England upheld strict standards of virtue for young women. The way society treats women weakens Mary's sense of agency makes her sexually vulnerable to predators like Harry Carson. Women in Gaskell's time had to secure their future by marrying, or face life unprotected and alone. As an unmarried woman, Mary does not fit comfortably within the confines of her society. It is not until her marriage to Jem that she has an ordered and secure position. Women could not make choices that jeopardized their marriage prospects, or they would face cruel consequences - like Esther, who ran off with a man she wasn't married to and ended up alone.
Real Love
Gaskell emphasizes Mary's realization of the difference between infatuation and love. Although Harry wants to possess Mary, and she knows that he marrying him would make her life more comfortable, Mary quickly comes to realize that Harry doesn't love her the way Jem does. Jem offers Mary solid, real and unconditional love. Harry's affection might be flashy, but Jem makes quiet sacrifices to ensure that Mary is always happy. Mary's choice of love over infatuation represents her maturation from childhood to adulthood.
The Value of Hard Work
John Barton demands his right to work so he can support his family. For him, hard work coincides with virtue and morality, and allows a man to feel responsible and capable. His downfall comes when he realizes he cannot do honest work because his employers are corrupt and unjust - and he lashes out as a result. As a contrast, Harry Carson lazes around all day and in his free time, he causes trouble for Mary Barton. Alternatively, Jem Wilson, like John Barton, works diligently to provide financially for his family, and Gaskell portrays him as noble and good as a result. Gaskell firmly supports the idea that idle hands do the devil's work. For the author and her characters, being a hard worker is tantamount to being a faithful Christian. The character of Mr. Carson is representative of this - as he transforms from a greedy mill owner into a hardworking, responsible employer after rediscovering his Christianity.
The Fragility of Life
Gaskell portrays working class life in Manchester as being haunted by sickness and death. As a result, her characters are aware of their mortality from a young age. Mary's mother dies when she is only thirteen and she continues to lose friends and family as she grows up. Certainly for the poor characters, their terrible living conditions contribute to the high mortality rate. However, Gaskell emphasizes that death can be around the corner for anybody. Harry Carson is wealthy and he meets death at an early age. Across classes, the constant threat of death forces Gaskell's characters to appreciate the value and beauty of life.
Female Virtue
The circumstances of Esther's life drive her to prostitution, but she is the most extreme example of a fallen woman in Mary Barton. In Victorian society, a woman's virtue was considered very fragile, and once it had been compromised - she could never repair it. Esther is ostracized and treated like the worst kind of sinner for the only profession that keeps bringing food to her table. None of the characters in the novel nor Gaskell herself criticize Esther's (presumably) male customers - the demand that necessitates the supply. Therefore, Gaskell also seems to believe that fallen women cannot be rehabilitated, although she does portray Esther with sympathy and kindness.
Drug Addiction
John Barton uses opium to dull his hunger pangs. Esther Barton becomes an alcoholic because she is ashamed of her life as a prostitute. Drug addiction in Victorian times was becoming a serious problem (especially amongst the working class), but there was little chance for recovery. Standards of morality would encourage society to reject drug addicts as wretched creatures who had strayed too far off a moral path. Unfortunately, society blamed the addict and not the addiction. These problems were only symptoms of a deeper issue - the strict moral codes that defined Victorian society.
