Stevenson explores the duality of human nature in many ways but the main one I found was though his characters

Stevenson explores the duality of human nature in many ways but the main one I found was though his characters. Stevenson uses the characters of Dr Jekyll and Mr Hyde to expresses his beliefs about human duality by introducing them as two contradictory characters, instead of just one character. Using two totally different characters with dissimilar names and appearances gets his message of human duality across more efficiently rather than using just one character.
We get introduce to Mr Hyde, a pale, short man and then we meet Dr Jekyll, a large, well-made man of fifty with a large good-looking face. The way Stevenson defines them as opposites makes us think that they are in fact two people, but as Stevenson builds up the clues throughout the book we start to realise that they are really the same person which I found very interesting and strange.
Stevenson uses Jekyll and Hyde to show the duality of human nature because by reading about the two characters separately, you would’ve never realised that they are the same person until Stevenson describes how Jekyll make a potion to separate good and evil, but as he drinks the potion it awakens a hidden character inside him, Mr Hyde. Jekyll enjoys having a secret life of being Hyde because he feels a sense of freedom because he can walk around Soho and other dark places where he can fulfil his desires without his reputation as a respectable doctor being put at risk. Stevenson is trying to tell us that everybody has evil inside of them and has a curiosity about their darker side. Jekyll seems to be in control of his desires and temptations but as Hyde he can achieve them and not feel guilty. Stevenson is stating that everybody has evil inside, deep down and he’s telling us that everyone gets a thrill of letting it out sometimes.
Jekyll thinks he’s in control of Hyde, his addiction to his darker side spirals out of control and he changes into Hyde without taking the potion. Hyde’s character is gaining strength and Jekyll is getting weaker. Jekyll gets weaker because he is getting weaker at controlling Hyde. By becoming Hyde and letting his evil side out, he has made live harder for himself because now he won’t be able to get rid of Hyde as he once said he could. Hyde has now overpowered Jekyll and is in control.
Everybody has good and evil inside them. The good in you should always be in control because if you let your evil side out too much it will take control of you and change you, just like Hyde changed Jekyll.
Stevenson’s purpose is to express that Hyde signifies the dark side inside of everybody and he explains how letting your evil side out can affect your life. Just like how Jekyll’s life got changed. He lost his friends and his mind, and it ruined his life. He used to be so jolly and honourable but now he is the complete opposite because becoming Hyde has ruined what he has worked for his whole life.