I'm having some trouble understand this quote in Mary Shelley's Frankenstein. If anyone out there is willing to contribute helping me, that would be great.

If, instead of this remark, my father had taken the pains to explain to me that the principles of Agrippa had been entirely exploded and that a modern system of science had been introduced which possessed much greater powers than the ancient, because the powers of the latter were chimerical, while those of the former were real and practical, under such circumstances I should certainly have thrown Agrippa aside and have contented my imagination, warmed as it was, by returning with greater ardour to my former studies. It is even possible that the train of my ideas would never have received the fatal impulse that led to my ruin. But the cursory glance my father had taken of my volume by no means assured me that he was acquainted with its contents, and I continued to read with the greatest avidity. When I returned home my first care was to procure the whole works of this author, and afterwards of Paracelsus and Albertus Magnus. I read and studied the wild fancies of these writers with delight; they appeared to me treasures known to few besides myself. I have described myself as always having been imbued with a fervent longing to penetrate the secrets of nature. In spite of the intense labour and wonderful discoveries of modern philosophers, I always came from my studies discontented and unsatisfied. Sir Isaac Newton is said to have avowed that he felt like a child picking up shells beside the great and unexplored ocean of truth. Those of his successors in each branch of natural philosophy with whom I was acquainted appeared even to my boy's apprehensions as tyros engaged in the same pursuit.

The untaught peasant beheld the elements around him and was acquainted with their practical uses. The most learned philosopher knew little more. He had partially unveiled the face of Nature, but her immortal lineaments were still a wonder and a mystery. He might dissect, anatomize, and give names; but, not to speak of a final cause, causes in their secondary and tertiary grades were utterly unknown to him. I had gazed upon the fortifications and impediments that seemed to keep human beings from entering the citadel of nature, and rashly and ignorantly I had repined.

What does this quote represent?