There are multiple themes to be found in "Frankenstein". As seen while viewing the symbols of the novel, light symbolizes knowledge. But aside from what you would think, there is a dark side to light. Too much of it can be detrimental, just as too much intelligence can be harmful. This is shown by the opposites in the novel, Frankenstein and Walton. They both went to extreme lengths in the search for great discovery, so much that they abandoned rational thought, and created their own peril. Where they differ is their limits on when to stop the madness. Frankenstein was so obsessed that he drove himself to death. This made Walton come to the realization of his irrationality, and pull back from his dangerous mission before he suffered the same fate as the doctor.