Course Hero. "Sophie's World Study Guide." Course Hero. 25 Oct. 2017. Web. 11 Dec. 2018. <https://www.coursehero.com/lit/Sophies-World/>.
Course Hero. (2017, October 25). Sophie's World Study Guide. In Course Hero. Retrieved December 11, 2018, from https://www.coursehero.com/lit/Sophies-World/
(Course Hero, 2017)
Course Hero. "Sophie's World Study Guide." October 25, 2017. Accessed December 11, 2018. https://www.coursehero.com/lit/Sophies-World/.
Course Hero, "Sophie's World Study Guide," October 25, 2017, accessed December 11, 2018, https://www.coursehero.com/lit/Sophies-World/.
A plane flies by with a banner wishing Hilde a happy birthday. Alberto begins his lesson on George Berkeley (1685–1753). Berkeley said, "the only things that exist are those we perceive." And yet, one cannot actually perceive matter, only the sensations derived from it. So one's sensations are ideas, not facts. Ideas have a cause beyond one's consciousness, but the cause is spiritual, not material. The existence of the world is due to God, who is the cause of "everything in everything." And so to Berkeley, humans exist "only in the mind of God."
Berkeley's philosophy leads to Sophie realizing she exists only in the mind of Albert. Alberto suggests that Albert may be writing to Hilde about them. Sophie runs home and is greeted by her mother, who hugs Sophie as she sobs.
Berkeley's philosophy has radical implications for the nature of existence—not only Sophie's existence, but for the existence of every human being on Earth. Alberto rightly points out to Sophie that Albert is a God to both of them. They exist because Albert willed them into being. Sophie and Alberto "cannot perceive the matter itself that [their] reality is made of." Their external reality could be sound waves (an audio book) or paper (a physical book). Berkeley would say their only certainty is that they are spirit.
The reader can take this a step further and realize that Albert himself is a creation of Gaarder. In this sense Gaarder is Albert and Hilde's God, existing only because Gaarder willed them into being. And it follows then that the reader must turn inward and ask who or what willed Gaarder (and the reader) into being? Other questions follow: Do humans on Earth exist in an actual physical world, or are they only figments of some great being's imagination? This is Gaarder's main thematic point of the novel: what is the nature of existence and can humans ever really know it?
Sophie is distraught by the realization her life may only be a dream, and the storm she runs through is a physical representation of her emotional state. It feels like her whole life is being torn apart, and, in a way, it is. Now awakening to the truth, she can never go back to her comfortable ignorance again.