De revolutionibus orbium coelestium divided into six "books" (sections or parts), following closely the layout of Ptolemy's "Almagest" which it updated and replaced: Copernicus argued that the universe comprised eight spheres. The outermost consisted of motionless, fixed stars, with the Sun motionless at the center. The known planets revolved about the Sun, each in its own sphere, in the order: Mercury, Venus, Earth, Mars, Jupiter, Saturn. The Moon, however, revolved in its sphere around the Earth. What appeared to be the daily revolution of the Sun and fixed stars around the Earth was actually the Earth's daily rotation on its own axis. Copernicus adhered
Against the Current: Essays in the History of Ideas Against the Current: Essays in the History of Ideas Against the Current: Essays in the History of Ideas (1979) is a collection of essays by 20th century philosopher and historian Isaiah Berlin. The collection was edited by Henry Hardy, and featured an introduction by Roger Hausheer. The book collects previously published essays in which Berlin discusses the thoughts of 20th century ideologic dissenters who were opposed to the prevailing wisdom of their time. A wide range of individuals are discussed including Machiavelli, Giambattista Vico, Montesquieu, Alexander Herzen, Georges Sorel, Verdi, and Moses Hess The collection represents Berlin's long-held interest in