Themes and Meanings
The American Revolution and the astronomical accuracy of the Mason-Dixon line are both the products of the Age of Reason, and the phrase recurs, rather anachronistically, throughout the novel. The first time it appears, ironically enough, it is spoken by a talking dog. The running of the line represents the imposition of an artificial order on nature’s mystery (among other things; it means something different to virtually every major character). The “right line” of rationality is opposed to the serpent of natural landscapes. For example, Maskelyne tells Mason about the serpent in the volcano on the island of St. Helena; Captain Zhang describes Chinese methods of surveying as the discovery of the Shan, or dragon, within the land; in a flashback, Dixon tells of a legendary dragon in his town; and the American Indians believe their serpent-mounds to be the work of a giant race.
The further Mason and Dixon penetrate into America, the more they discover the irrational, the dream world of the new land. A sign of their growing closeness is Mason and Dixon’s compact to tell each other each night’s dream. By the end of the novel, they are experiencing the same dream. Even the narrator records one of his dreams, and it seems to be a part of the adventures of Mason and Dixon. America is tentatively called “sleeping Brittania’s dream,” and a Delaware philosopher tells the surveyors that the Indians are the dreams of the Europeans. As the exploration of the American interior becomes more and more associated with the interiority of the mind, Dixon hears legends of a passage into the interior of the earth, which, near the end of his life, he claims to have visited. Ironically, the experiment that rendered this popular speculation scientifically implausible was proposed in 1772 by Maskelyne, Mason and Dixon’s companion in the early years; the experiment involves taking latitude readings on two sides of a mountain, research Pynchon has Dixon doing at the opening of chapter 75.