Why young Victor left natural philosophy and switched to mathematics?

In Chapter Two, we learn that Victor is preoccupied with the question of how one might communicate with ­or even raise ­the dead. He finds no answer in the works of his Roman idols, and he becomes entirely disillusioned with them when he witnesses a lightning storm. Since the Romans have no satisfactory explanation for this phenomenon, Victor renounces them entirely and devotes himself (at least for the time being) to the study of mathematics.