Cosmology and Astronomy

Ptolemy's planetary theory matched observations, but in Copernicus's opinion, it violated the standard of uniform circular motion. Also, Ptolemy's scheme did not automatically produce phenomena that followed naturally in Copernicus's heliocentric model. An unauthorized foreword to Copernicus's 1543 De revolutionibus orbium coelestium presented the heliocentric theory as a convenient mathematical fiction. Copernicus, however, believed that he was describing the real world.

Revolutions in science, as in politics, often exceed the limited changes envisioned by their creators. The sphere carrying the stars was now obsolete, and soon human imagination distributed the stars throughout an infinite space. Furthermore, the earth was no longer unique. Galileo's telescopic observations emphasized that the moon was uneven and rough, like the earth. Also, Jupiter had four satellites similar to the earth's satellite.

Logical consequences of the Copernican system, Galileo's telescopic discoveries, and the principle of plenitude, which interpreted any unrealized potential in nature as a restriction of the Creator's power, all encouraged belief in a plurality of worlds. Also, political and societal critics used the moon as a literary convention, its inhabitants' arrangements being either a model of perfection or a mirror of the earth's vices. Faith in an anthropocentric universe lay shattered, leaving people's relationship with God uncertain. John Donne's 1611 poem An Anatomy of the World, its line the "new Philosophy calls all in doubt," and later "all Relation: / Prince, Subject, Father Son, are things forgot," refers to Christian morality as much as to the relative positions of the sun and earth.