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. (2.7)
The secret nature of scientific knowledge prompts Victor’s obsessive desire to go deeper in his quest for the secret of life.
The world was to me a secret which I desired to divine. Curiosity, earnest research to learn the hidden laws of nature, gladness akin to rapture, as they were unfolded to me, are among the earliest sensations I can remember. (2.1)
The laws of nature are described as a hidden secret.
It was the secrets of heaven and earth that I desired to learn; and whether it was the outward substance of things or the inner spirit of nature and the mysterious soul of man that occupied me, still my inquiries were directed to the metaphysical, or in it highest sense, the physical secrets of the world. (2.4)
One of the phenomena which had peculiarly attracted my attention was the structure of the human frame, and, indeed, any animal endued with life. Whence, I often asked myself, did the principle of life proceed? It was a bold question, and one which has ever been considered as a mystery; yet with how many things are we upon the brink of becoming acquainted, if cowardice or carelessness did not restrain our inquiries. I revolved these circumstances in my mind and determined thenceforth to apply myself more particularly to those branches of natural philosophy which relate to physiology. Unless I had been animated by an almost supernatural enthusiasm, my application to this study would have been irksome and almost intolerable. To examine the causes of life, we must first have recourse to death. I became acquainted with the science of anatomy, but this was not sufficient; I must also observe the natural decay and corruption of the human body. In my education my father had taken the greatest precautions that my mind should be impressed with no supernatural horrors. I do not ever remember to have trembled at a tale of superstition or to have feared the apparition of a spirit. Darkness had no effect upon my fancy, and a churchyard was to me merely the receptacle of bodies deprived of life, which, from being the seat of beauty and strength, had become food for the worm. Now I was led to examine the cause and progress of this decay and forced to spend days and nights in vaults and charnel-houses. My attention was fixed upon every object the most insupportable to the delicacy of the human feelings. I saw how the fine form of man was degraded and wasted; I beheld the corruption of death succeed to the blooming cheek of life; I saw how the worm inherited the wonders of the eye and brain. I paused, examining and analysing all the minutiae of causation, as exemplified in the change from life to death, and death to life, until from the midst of this darkness a sudden light broke in upon me--a light so brilliant and wondrous, yet so simple, that while I became dizzy with the immensity of the prospect which it illustrated, I was surprised that among so many men of genius who had directed their inquiries towards the same science, that I alone should be reserved to discover so astonishing a secret. (4.3)
Victor discovers the secret to life and feels astonished that he should be the one to figure it out.
Who shall conceive the horrors of my secret toil as I dabbled among the unhallowed damps of the grave or tortured the living animal to animate the lifeless clay? (4.9)
Victor’s obsessive drive to create life forces him into secret "horrors."
I saw plainly that he was surprised, but he never attempted to draw my secret from me; and although I loved him with a mixture of affection and reverence that knew no bounds, yet I could never persuade myself to confide in him that event which was so often present to my recollection, but which I feared the detail to another would only impress more deeply. (6.12)
Victor feels disconnected from Henry because he is keeping his knowledge as well as his monster a secret.
I avoided explanation and maintained a continual silence concerning the wretch I had created. I had a persuasion that I should be supposed mad, and this in itself would forever have chained my tongue. But, besides, I could not bring myself to disclose a secret which would fill my hearer with consternation and make fear and unnatural horror the inmates of his breast. I checked, therefore, my impatient thirst for sympathy and was silent when I would have given the world to have confided the fatal secret. Yet, still, words like those I have recorded would burst uncontrollably from me. I could offer no explanation of them, but their truth in part relieved the burden of my mysterious woe. (22.4-5)
Victor feels that his creation is a secret burden that cannot be relieved.
My father had often, during my imprisonment, heard me make the same assertion; when I thus accused myself, he sometimes seemed to desire an explanation, and at others he appeared to consider it as the offspring of delirium, and that, during my illness, some idea of this kind had presented itself to my imagination, the remembrance of which I preserved in my convalescence.
The secrecy of Victor’s discovery makes him appear crazy to those around him.