Robert Louis Stevenson’s Strange Case of Dr Jekyll and Mr Hyde features the theme of the doppelganger. Victorian novels often use this theme (or motif), with doppelganger meaning a double. The doppelganger character can be considered the main character's evil twin, who can act beyond the social norms that bind the other characters.
The doppelganger also creates conflict in the story. This can be an external conflict where there main character is fighting his double, or an internal conflict where the main character is struggling to reconcile his good and evil sides.
Strange Case of Dr Jekyll and Mr Hyde is concerned with the double and the fundamental duality of human nature. Dr Jekyll learns this from his experience and his experiments: “I thus drew steadily nearer to the truth, by whose partial discovery I have been doomed to such a dreadful shipwreck: that man is not truly one, but truly two.” (p. 52)
Dr Jekyll knows that he is a mixture of good and evil:
I learned to recognise...