In Chapter 2 of Frankenstein, Victor begins the study of mathematics, but it is "destiny" that causes him to change his course of study to natural philosophy:
Before this I was not unacquainted with the more obvious laws of electricity. On this occasion a man of great research in natural philosophy was with us, and, excited by this catastrophe, he entered on the explanation of a theory which he had formed on the subject of electricity and galvanism, which was at once new and astonishing to me. All that he said threw greatly into the shade Cornelius Agrippa, Albertus Magnus, and Paracelsus, the lords of my imagination; but by some fatality the overthrow of these men disinclined me to pursue my accustomed studies. It seemed to me as if nothing would or could ever be known. All that had so long engaged my attention suddenly grew despicable. By one of those caprices of the mind, which we are perhaps most subject to in early youth, I at once gave up my former occupations; set down natural history and all its progeny as a deformed and abortive creation; and entertained the greatest disdain for a would-be science, which could never even step within the threshold of real knowledge. In this mood of mind I betook myself to the mathematics, and the branches of study appertaining to that science, as being built upon secure foundations, and so worthy of my consideration.
It is destiny that causes him to meet M. Waldman, who develops Victor's passion for the natural sciences of galvanism, electromagnetism, and alchemy. Victor might have been a good mathematician, if he were devoid of passion. But his passion causes him to pursue his dreams and the God-like ideal, and so he seeks intuitively to seek the answers to stopping death through the life sciences.
The Romantics believed heavily in destiny. To them, it was the inevitable by-product of their passions. So says Victor:
"I would account to myself for the birth of that passion, which afterwards ruled my destiny, I find it arise, like a mountain river, from ignoble and almost forgotten sources; but, swelling as it proceeded, it became the torrent which, in its course, has swept away all my hopes and joys.
Victor ends the chapter thusly:
It was a strong effort of the spirit of good; but it was ineffectual. Destiny was too potent, and her immutable laws had decreed my utter and terrible destruction.
This brash idealism will cause Victor to rationalize his abuses of science (playing God and isolating himself from others, all for the sake of discovery). His belief in passion and destiny is reckless. Perhaps the world would have been safer if he had chosen mathematics.