What is the theme of destiny in Frankenstein by Mary Shelley?
Although Victor Frankenstein and Captain Robert Walton seem to believe that they are destined for greatness, that they would make discoveries which significantly and positively impact humanity, the book itself reveals that destiny is not, ultimately, in control of our lives; rather, it is our choices that determine our futures. The monster Victor creates blames his father for his neglect as well as the monster's physical appearance; however, he chooses to be good and kind for quite a while, despite his harsh treatment from others. Later, after he realizes that he also has power to make his creator miserable (when he kills William), he chooses to become evil and vengeful, killing innocents in order to exact his revenge on Victor. He is not destined or compelled by some force outside himself to murder Victor's loved ones; he exercises his free will in order to make his creator pay.
Likewise, Walton exercises his will in the end to turn away from the greatness he seeks. When his crew is unwilling to continue their voyage as a result of the grave personal danger it poses, Walton will not take their lives into his hands, and so he turns back (even though he really doesn't want to). This choice also shows that destiny is not controlling him; he can and does make a decision antithetical to his original goal. Therefore, we can see that free will, not destiny, is ultimately the controlling force for Shelley.