Works of Galileo Galilei, Part 4, Volume 2, Astronomy: Dialogue Concerning the Two Chief World Systems


This manuscript of 1632 contains an incomplete, autographical editing of Dialogo sopra i massimi sistemi del mondo (Dialogue concerning the two chief world systems) by the Italian scientist and mathematician Galileo Galilei (1564–1642). The text of this version, at the National Central Library in Florence, is very close to the definitive manuscript prepared for print (the complete autographical version of the text is in the Seminary Library in Padua). Published in 1632, the Dialogo had occupied Galileo for six years and is one of his most important works. It takes the form of a discussion among a spokesman for Copernicus, a spokesman for Ptolemy and Aristotle, and an educated layman who the two spokesmen attempt to win over. The church had issued an edict in 1616, which prohibited Galileo from teaching the Copernican view of the solar system. Galileo traveled to Rome in 1624 to meet with Pope Urban VIII, who refused to lift the edict but gave Galileo permission to discuss the Copernican system in a book, provided he gave equal and impartial treatment to the geocentric view associated with Ptolemy and Aristotle. The Dialogo reflects Galileo’s attempt to advance his scientific views while observing the letter of the church’s order.

Last updated: September 18, 2015