Who is the narrator in Frankenstein?

My temper was sometimes violent, and my passions vehement; but by some law in my temperature they were turned not towards childish pursuits but to an eager desire to learn, and not to learn all things indiscriminately. I confess that neither the structure of languages, nor the code of governments, nor the politics of various states possessed attractions for me. 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 its highest sense, the physical secrets of the world.

And what does this quote mean?