To understand the Victorian context of Robert Louis Stevenson's The Strange Case of Dr. Jekyll and Mr. Hyde, one must look to "utilitarianism," also known at that time as "Bethamism," a prevalent, social "belief system" in Victorian England.
One source defines utilitarianism as:
Actions are right to the degree that they tend to promote the greatest good for the greatest number.
The idea was that the pleasure of many was more important that the pleasure of the few.
eNotes.com's historical context of the novel states:
At the heart of this belief was the supposition that self-interest should be one's primary concern...happiness could be attained by avoiding pain and seeking pleasure. In Victorian People and Ideas, Richard D. Altick explains that "utilitarianism was ... wholly hedonistic; it made no allowance for the promptings of conscience, or for ... the forces of generosity, mercy, compassion, self-sacrifice, love. Benthamite ethics had nothing to do with Christian morality."
Basically, the Victorian era was about feeling good rather than feeling bad. This is a major point in the "case" of Dr. Jekyll and Mr. Hyde. Dr. Jekyll comes up with a formula that will make him stronger and fitter, however, there is a sacrifice to be made: Mr. Hyde (Jekyll's alter-ego) is much smaller, and while he has great strength, he is evil personified.
The reflection of Victorian attitudes can be seen in the following with regard to the theme of "freedom." This was especially important to Dr. Jekyll:
When he becomes Hyde he notes, 'I felt younger, lighter, happier in body; within I was conscious of...an innocent freedom of the soul.' The freedom he experiences results from the release of his inner desires, which, being a respectable Victorian gentleman, he previously had to suppress.
The theme of good vs. evil is also a central element in the story. Stevenson provides the reader with a glimpse into the struggle within Dr. Jekyll, and he is pulled between the good (morality) and evil (giving in to one's desires).
G. B. Stern in his book on Stevenson argues that the novel is 'a symbolic portrayal of the dual nature of man, with the moral inverted: not to impress us by the victory of good over evil, but to warn us of the strength and ultimate triumph of evil over good once sin is suffered to enter human habitation.'
Stevenson has written a novel of warning: the dangers of living a freely Victorian lifestyle may come at the cost of one's soul. The author, Stern proposes, warns of the power of evil to triumph when given free rein.
However, counter to utilitarianism is Protestant Evangelicalism.
Evangelicalism focused...more on the day-to-day lives and eventual salvation of its followers, [setting] patterns of conduct...to follow in order [to be forgiven] for their sins. Altick notes that "the Evangelical's anxious eye was...fixed upon the 'eternal microscope' which searched for every moral blemish...[It] is also noted for its inspiration of humanitarian activities during the Victorian age.
The Jekyll vs. Hyde dilemma may be seen as a representation of the human condition: one struggles to do what is right, is tempted by what is wrong, and must learn how to balance the two or be lost: which is what transpires in the novel. Jekyll is lost in order to save the world from the evil of Mr. Hyde: an uncontrolled aspect of Dr. Jekyll's psyche.