William H. Goetzmann, alone this time (see below), in a specific look at the urge to exploration during the two centuries from the 1600's to the 1800's, particularly in relation to America. Goetzmann, who twice before has tackled the exploratory impulse (in Army Exploration in the American West and in Exploration and Empire), sees this period as a neat split with the older concept of scientific exploration, as epitomized by Columbus. What Goetzmann calls the Second Great Age of Discovery depended upon the process of ""secular, scientific system-building"" that countered the certainties of medieval Christianity. In outlining his conceptions, the author secondarily theorizes that this new age consequently ""set the values, tone and rhythm of American culture from the eighteenth century to the present. . ."" Exploration must have objectives, and Goetzmann Finds several in this second great age: first, the pursuit of science and progress for its own sake; second, a drive for precision, particularly in relation to cartography; and third, the pursuit of ""calculated empiricism."" Goetzmann insists that American exploration was certainly not a peripheral activity, as it is often viewed. It was central, he feels, to the American experience. The whole concept of Romanticism, for example, can arguably be credited to the return of explorers broadened by their experiences. A thoughtful exploration, in its own right.