Quinta pars or terra incognita? Verisimilitude in the cartographic representation of the unknown

CARLA LOIS

Berkeley

Conferencia; Mapping and the Global Imaginary, 1500-­‐1900; 2019

David Rumsey Map Center, Stanford University

Since the early sixteenth century and during more than two hundred years, world maps showed a huge southern landmass marked as terra incognita, mostly known as the Magellanica (after Ferdinand Magellan) or Quinta Pars or ?fifth part? of the world.Because there was no concrete evidence behind its cartographic depiction (for the Quinta Pars simply did not exist), and its existence was based merely on plausible conjectures, this case allows us to analyze the philosophical conceptions, the epistemological bases, the intellectual and scientific methods involved in imagining and representing unknown geographies, avoiding the temptation to compare this with ?reality,? and thus try to measure errors or inaccuracies. This perspective implies a reflection not about how the unknown became known, but rather about how the unknown is conceived as unknown.I will argue that the New World made the existence of the austral continent plausible: the Quarta Pars made the Quinta Pars possible, thinkable, reliable, credible and verisimilar. Explorers mapped ?points? (which actually were parts of islands seen from long distances), traced lines uniting them, and then built up a huge landmass, putting in action cartographical imagery, and cosmographical systems that had worked to imagine the New World during the first half of the sixteenth century. The Quarta Pars seems to have been the ?condition of verisimilitude? for the existence of the Quinta Pars because it allowed a rational evaluation of available empirical evidence while no counter-facts invalidate the theory. This presentation raises questions regarding the epistemological challenges that the Quinta Pars introduced into the Renaissance discourse on the unknown (why has the general belief in the Quinta Pars been accepted as geographical knowledge?); and the aesthetic components involved in the representation of the unknown in cartography: graphic patterns (colors, lines, shapes), iconography (symbols, allegories, mirabilia), toponomys (place-names, indications about the degree of available or reliable knowledge).