suspend my mind up high,to mix my subtle thoughts with what's like them—the air. If I turned my mind to lofty things,but stayed there on the ground, I'd never makethe least discovery. For the earth, you see,draws moist thoughts down by force into itself—the same process takes place with water cress. Early Taoist philosopher Zhuang Zhou expressed his ideas primarily through short literary anecdotes and fables such as "Dream of the Butterfly". The other major philosophers of the time appear as characters within these stories, allowing Zhuangzi to playfully explore their ideas and contrast them with his own, as he does with Laozi, Liezi, Hui Shi, and many others. Most prominently in his work is the presence of Confucius and his prominent disciples, who are sometimes used to undermine popular understandings of Confucian philosophy or to reinforce Zhuangzi's own understanding of how one lives in accordance with the Dao. Jorge Luis Borges is perhaps the twentieth century's preeminent author of philosophical fiction. He wrote a short story in which the philosopher Averroes is the chief protagonist, Averroes's Search. Many plot points in his stories paraphrase the thought of philosophers, including George Berkeley, Arthur Schopenhauer, and Bertrand Russell; he also attributes various opinions to figures including George Dalgarno. A key plot point in Umberto Eco's novel The Name of the Rose turns on the discovery of a mysterious book that turns out to contain a lost manuscript by Aristotle. Eco's later novel Foucault's Pendulum became the forerunner of a run of thrillers or detective fiction that toss around learned allusions and the names of historical thinkers; more recent examples include Dan Brown's The Da Vinci Code and The Rule of Four by Ian Caldwell and Dustin Thomason. Also, Philip K. Dick, who has often been compared to Borges, raises a significant number of philosophical issues in his novels, everything from the problem of solipsism to many questions of perception and reality. Fictional philosophers Jorge Luis Borges introduces many philosophical themes, and a number of fictional philosophers, in his short stories. A fictional philosophical movement is a part of the premise of his story Tlön, Uqbar, Orbis Tertius, and the unnamed narrator of his story The Library of Babel could also be called a fictional philosopher. A fictional theologian is the subject of his story Three Versions of Judas. Fictional philosophers occasionally occur throughout the works of Robert A. Heinlein and Ray