In temperament, Elizabeth is very much a foil to Victor. Their differences help us to see how he, with his character and aptitudes, could go on to create the "monster" that he does. He tells Walton, "Elizabeth was of a calmer and more concentrated disposition; but, with all my ardour, I was capable of a more intense application and was more deeply smitten with the thirst for knowledge." While Elizabeth was calm and focused, Victor was more intense with a greater will to persist; he wanted more desperately than she to know and understand things.
Further, Victor says,
She busied herself with following the aerial creations of the poets; and in the majestic and wondrous scenes which surrounded our Swiss home --the sublime shapes of the mountains, the changes of the seasons, tempest and calm, the silence of winter, and the life and turbulence of our Alpine summers--she found ample scope for admiration and delight. While my companion contemplated with a serious and satisfied spirit the magnificent appearances of things, I delighted in investigating their causes.
Elizabeth was interested in poetry, nature, and the beauty of the world around her, and she was content to admire and take delight in these things. Victor, on the other hand, was not satisfied with feeling admiration and delight; instead, he wanted to investigate, to find out the reasons why the world is the way the world is. His interest is much more active than hers. He even makes her interest sound much more concerned with surfaces, as though she was satisfied with "appearances" while he desired to dig deeper and deeper. In this way, then, Elizabeth serves as a foil to really contrast Victor's temperament.
Elizabeth Lavenza can be defined as a foil to Victor Frankenstein (Mary Shelley's Frankenstein). A foil is a character whose characteristics contrast another character so that the characteristics can be highlighted.
Initially, Elizabeth foils Victor regarding her adoption into the Frankenstein family. Victor is the natural born child of the Frankensteins. Elizabeth has been saved from poverty and brought into the home. Here, Elizabeth is both female and not a natural child of the family. These characteristics are important when examining some of the themes of the novel: nature verses science, appearance verses reality, and nature verses nurture.
Later, Elizabeth's love of all natural contrasts Victor's love of all scientific. Elizabeth is satisfied with the world around her not changing (the mountains, lake, and scenery of her home)--it is important because it contrasts Victor's desire to change the world.
Lastly, Elizabeth's concern for Victor (when he is obsessed with reanimating life) exists because of her love for him. On the other hand, Victor's concern for himself lapses; he fails to concern himself with his own life (when trying to create another). In essence, his obsession with science is again contrasted with Elizabeth's love for nature.
The character who is normally considered the foil to Victor in Frankenstein is Henry Clerval, a close friend of Victor similar in background and intellectual interests, but possessing a better moral compass and considerably less arrogant. Although it is possible to think of Elizabeth in contrast to Victor, she is not his major foil in terms of the structure of the novel.
Elizabeth Lavenza is Victor's foster sister. She differs from Victor because she does not have the sense of hereditary entitlement that he does. Instead, she relies on her own character and virtues to be an admirable person. She is gentle and loving—and lacks Victor's ambition—but is morally superior to him by being compassionate whereas he is self-centered. While Victor is the cause of the monster's crimes, Elizabeth is the monster's victim. Elizabeth loves the world as it exists, while Victor tries to change the world. Victor is active, and Elizabeth is passive. Victor is motivated by intellect and pride, whereas Elizabeth is driven by love and compassion. Elizabeth is gentle, and Victor is aggressive. Elizabeth embodies traditional feminine virtues and is subsequently victimized, but Victor causes problems because of his traditional masculinity.