Berkeley, George. A Treatise Concerning the Principles of Human Knowledge. 1710.
Greene, Brian. The Elegant Universe: Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory. New York: Norton, 1999. See also the three-part companion NOVA series, available from PBS.
Greene, Brian. The Fabric of the Cosmos: Space, Time, and the Texture of Reality. New York: Vintage, 2004. See also the four-part companion NOVA series, available from PBS.
Greene, Brian. The Hidden Reality: Parallel Universes and the Deep Laws of the Cosmos. New York: Vintage, 2011.
Kant, Immanuel. Critique of Pure Reason. 1781, 1787.
Randall, Lisa. Knocking on Heaven’s Door: How Physics and Scientific Thinking Illuminate the Universe and the Modern World. New York: HarperCollins, 2011.
Smith, Huston. The World’s Religions. New York: Harper Collins, 1991.
Wolchover, Natalie. “Is Nature Unnatural? Decades of Confounding Experiments Have Physicists Considering a Startling Possibility: The Universe Might Not Make Sense.” Simons Science News (May 24, 2013). (https://www.simonsfoundation.org/features/science-news/is-nature-unnatural/)