Duality of human nature
The duality of human nature is the philosophical and psychological core of Robert Louis Stevenson's Strange Case of Dr Jekyll and Mr Hyde. Henry Jekyll, reflecting on his own life, formulates the concept as the "thorough and primitive duality of man" — the conviction that every human being is not a single, unified self but a compound of two distinct and warring natures, one good and one evil. This belief, born from his own experience of a divided life and his scientific studies in the mystic and transcendental, becomes the theoretical foundation for his experiments. He comes to see that "man is not truly one, but truly two," and he speculates that humanity will ultimately be known as "a mere polity of multifarious, incongruous and independent denizens." This idea is not merely abstract; it is the engine of the entire narrative, from Jekyll's creation of the transformative drug to the eventual destruction of both himself and Edward Hyde.
Origins in Jekyll's Divided Life
Jekyll's theory of duality arises directly from his personal experience of a profound duplicity. Born to a large fortune and endowed with excellent parts, he was inclined by nature to industry and fond of the respect of the wise and good. Yet his worst fault was a "certain impatient gaiety of disposition" that he found hard to reconcile with his "imperious desire to carry my head high, and wear a more than commonly grave countenance before the public." Consequently, he concealed his pleasures and stood "committed to a profound duplicity of me." He insists that he was "in no sense a hypocrite; both sides of me were in dead earnest" — he was no more himself when he laid aside restraint than when he labored in the eye of day at the furtherance of knowledge. This internal war, which he calls "the perennial war among my members," drove him to reflect deeply on "that hard law of life, which lies at the root of religion." Even before his scientific discoveries suggested the possibility of separation, he had learned "to dwell with pleasure, as a beloved daydream, on the thought of the separation of these elements." He imagined that if each nature could be housed in separate identities, life would be relieved of all that was unbearable: the unjust could go his way, delivered from the aspirations and remorse of his more upright twin, while the just could walk steadfastly on his upward path, no longer exposed to disgrace and penitence.
The Scientific Discovery and Its Flaw
Jekyll's scientific studies, which led wholly toward the mystic and the transcendental, shed a strong light on his consciousness of duality. He began to perceive "the trembling immateriality, the mistlike transience, of this seemingly so solid body in which we walk attired" and found agents that could "shake and pluck back that fleshly vestment." He managed to compound a drug that could dethrone the powers of his natural body from their supremacy and substitute a second form and countenance, one that bore the stamp of the lower elements in his soul. However, the drug had "no discriminating action; it was neither diabolical nor divine; it but shook the doors of the prisonhouse of my disposition." Because at the time of his first experiment his virtue slumbered while his evil, kept awake by ambition, was alert and swift to seize the occasion, the thing that was projected was Edward Hyde — pure evil. Jekyll later reflects that had he approached his discovery "in a more noble spirit, had I risked the experiment while under the empire of generous or pious aspirations, all must have been otherwise, and from these agonies of death and birth, I had come forth an angel instead of a fiend." The movement was thus "wholly toward the worse."
The Consequences of the Divided Existence
The duality, once made literal, produces a cascade of consequences that Jekyll cannot control. He discovers that Edward Hyde, being the less exercised and less exhausted side of his nature, is smaller, slighter, and younger than Henry Jekyll. Yet Hyde's evil is absolute: "all human beings, as we meet them, are commingled out of good and evil: and Edward Hyde, alone in the ranks of mankind, was pure evil." Jekyll initially enjoys the freedom of his double existence, able to "plod in the public eye with a load of genial respectability, and in a moment, like a schoolboy, strip off these lendings and spring headlong into the sea of liberty." But the balance of his nature begins to shift. He experiences an involuntary transformation in his bed, waking to find his hand has become the lean, corded, hairy hand of Hyde. He realizes that "the body of Edward Hyde had grown in stature" and that the power of voluntary change might be forfeited. The difficulty, which had once been to throw off the body of Jekyll, gradually transfers to the other side: he is "slowly losing hold of my original and better self, and becoming slowly incorporated with my second and worse." The two natures, though sharing memory in common, develop a mutual hatred. Jekyll sees Hyde as "something not only hellish but inorganic" — "the slime of the pit" that utters cries and voices — yet Hyde is "knit to him closer than a wife, closer than an eye; lay caged in his flesh, where he heard it mutter and felt it struggle to be born." Hyde, for his part, loathes the necessity of returning to Jekyll's subordinate station and plays "ape-like tricks," scrawling blasphemies in Jekyll's own hand and destroying the portrait of Jekyll's father.
The Final Collapse of the Dual System
The duality ultimately proves unsustainable. Jekyll's original supply of the salt that gave the drug its efficacy was impure, and when it runs low, no fresh supply works. He becomes trapped in the body of Hyde, able to maintain the form of Jekyll only through a great effort and under the immediate stimulation of the dwindling drug. At all hours, he is taken with premonitory shudders; if he sleeps or even dozes for a moment, he awakens as Hyde. The powers of Hyde seem to grow with the sickliness of Jekyll. In his final statement, Jekyll writes that he is finishing it "under the influence of the last of the old powders" and that this is "the last time, short of a miracle, that Henry Jekyll can think his own thoughts or see his own face." He brings the life of "that unhappy Henry Jekyll" to an end, leaving Hyde to face the scaffold or to find the courage to release himself. The duality, which Jekyll had dreamed of as a liberation, has become a prison from which the only escape is death.
