Themes: Duality, Repression and Science
Theme 1: Duality
Duality is the novella’s central theme. Stevenson argues that every human being contains both good and evil, and that trying to separate them is both impossible and dangerous.
Jekyll’s experiment is an attempt to split his “dual nature” into two separate beings. He describes “those provinces of good and ill which divide and compound man’s dual nature.” But the experiment fails because good and evil are not separable — they are woven into the fabric of every person.
Duality operates at every level of the novella: character (Jekyll/Hyde), setting (respectable front/decayed laboratory), narrative (multiple perspectives), and even the title (“Strange Case” suggests something that defies rational explanation).
Jekyll’s house has a grand, respectable front entrance on a “square of ancient, handsome houses” and a neglected back door opening onto a “blind forehead of discoloured wall.” The two entrances represent Jekyll’s two identities. Hyde uses the back door — literally entering through the hidden, shameful side of Jekyll’s life.
London itself is presented as a city of contrasts: wealthy streets sit alongside impoverished Soho; fog obscures the boundaries between respectability and vice. Stevenson uses the motif of fog to suggest that moral clarity is impossible in a society built on concealment.
Theme 2: Repression
Repression drives the entire plot. Jekyll creates Hyde because Victorian society demands that he suppress every “undignified” impulse. Rather than allowing himself small, harmless pleasures, he must maintain a facade of total respectability.
Stevenson’s message is clear: repression does not eliminate desire — it intensifies it. Jekyll’s suppressed urges, when finally released as Hyde, take their most extreme and violent form. If Jekyll had been able to live a more balanced life, he would never have needed the experiment.
Repression is not unique to Jekyll. Utterson denies himself the theatre and good wine. Enfield makes a “bargain” never to speak of Hyde again. Even Poole suppresses his fear until breaking point. Every character in the novella practises some form of self-denial, reflecting a society where concealment is a way of life.
The novella is set in an almost entirely male world. There are no significant female characters. This intensifies the theme of repression — Victorian masculinity demanded emotional restraint, self-control and the suppression of vulnerability.
Theme 3: Science and Its Limits
Jekyll’s experiment is a scientific endeavour — he mixes chemicals to create the transformative potion. But the experiment crosses a moral boundary. Lanyon calls it “unscientific balderdash” because he believes Jekyll has gone “wrong in mind” and abandoned proper scientific method. Stevenson’s own point is different: the chemistry works, and it is the moral cost that destroys Jekyll.
Stevenson wrote during a period of intense scientific debate. Darwin’s theory of evolution had shaken religious certainties. New research into psychology was suggesting that the human mind was more complex — and darker — than previously believed. The novella asks: should science explore every corner of human nature, even if the discoveries are horrifying?
Like Victor Frankenstein in Mary Shelley’s novel, Jekyll is a scientist who oversteps moral boundaries and creates a monster he cannot control. Both texts belong to the Gothic tradition, which frequently uses science as a source of horror. The message in both texts is similar: scientific ambition without moral restraint leads to destruction.
How the Themes Connect
The three themes are deeply interlinked. Victorian repression creates the conditions for Jekyll’s experiment. His scientific ambition provides the means. And the result reveals the duality at the heart of human nature. Stevenson’s novella is ultimately a warning: a society that refuses to acknowledge the darker side of human nature will be destroyed by it.