How are Dr. Jekyll and Victor Frankenstein lonely and isolated men?
Frankenstein is the archetypal novel on the theme of man playing God: it arose as a result of the changing Enlightenment ideas that generated fear in the early nineteenth century about the role of man in the universe—and about the rise of scientific understanding. Dr. Jekyll and Mr. Hyde, meanwhile, is part of the late Victorian revival of this Gothic theme (compare also H. G. Wells's novel The Island of Dr. Moreau). Dr. Jekyll, the protagonist, consciously embodies many of the traits of Shelley's Victor Frankenstein, as both men are intelligent and accomplished men of science who are pushed into the shadows of society because of their devotion to the unnatural.
Victor Frankenstein starts out as a character with close personal friends who behaves in a rational way. However, as he becomes increasingly devoted to his gruesome task, he must visit places that take him outside the realms of civilized society. The more Frankenstein occupies the "charnel houses" of his adopted hometown and removes himself from the company of other students, the deeper he falls into questionable practices that others would not understand. Frankenstein is convinced that his work is valid, but he knows others will not see things the same way: the novel makes the reader question whether the creature is the monstrous thing, or if it is Frankenstein himself who is the monster for having behaved so unnaturally in attempting to create life.
Dr. Jekyll, too, condemns himself to a life of isolation, but in his case, the "monster" is part of himself. There is no question as to whether he or the creation is the evil element: the suggestion is that, by conducting his unnatural experiments, Jekyll has let loose the buried immoral part of himself that, perhaps, exists in all humans. As Mr. Hyde continues to commit increasingly depraved crimes, Jekyll must sink further into isolation, reaching a point where he cannot control the emergence of the beast within. Like other late Victorian works, such as Wilde's Dorian Gray, Dr. Jekyll and Mr. Hyde explores fin-de-siecle concerns about immorality and criminal degeneracy as potentially only hovering below the surface, awaiting any moment to escape and wreak havoc.
Both Dr. Jekyll and Victor Frankenstein undertake ethically questionable experiments in order to improve their own, as well as the human, experience. Dr. Jekyll hopes to separate humankind's baser impulses so that anyone who quaffs the potion he creates can more easily live in accordance with Victorian social mores. Frankenstein hopes to render humankind invulnerable to disease and decay.
For both of these men, their attempts to better humankind are founded on more selfish impulses. Jekyll has trouble controlling himself and so hopes to separate out his darker side so that he no longer desires to do things that society considers "bad." Frankenstein hopes to be known as the creator of a new race of men that would bless him. Neither one seems to really consider how their experiments could go horribly wrong.
It seems as though they are both punished for their selfishness and lack of forethought with loneliness and isolation. Jekyll loses control when Hyde, his alter ago, assumes control over his person, and Frankenstein's creature kills the majority of his friends and family in an effort to render his creator as miserable as he finds himself to be. Both become incredibly lonely and sad as a result of their isolation.
Both Henry Jekyll and Victor Frankenstein are obsessed with scientific ideas/experiments that go against the ethics of society. They are forced to practice in secret, not even sharing their outlandish (and what some may call heretical) ideas with their closest frieinds or relatives. Henry Jekyll creates a potion that allows him to disguise himself from society (as Edward Hyde) and to do all of the unspeakable acts he secretly desires while still maintaining his respectable reputation as a doctor. When the experiment gets out of control, and Henry Jekyll can no longer "conjure" Edward Hyde at will because Hyde's personality emerges unexpectedly, Jekyll is forced to isolate himself. In Frankenstein, Victor Frankenstein tries to play God in bringing life to dead flesh. When he succeeds in doing so, he immediately abandons the creature in disgust; however, who can he tell about it? No one! So he keeps his secret to himself, and that knowedge eats away at him, especially when the creature begins to kill Victor's family. In these ways, both Henry Jekyll and Victor Frankenstein become lonely, isolated men.