Descartes was putting the finishing touches on The World when, in the fall of 1633, he heard about the condemnation of Galileo. As a consequence, he decided not to publish his treatise, as the hypothesis of the earth's motion could not be removed from it “without rendering the whole work defective” (AT I 271, CSMK 41) (see earth, motion of the). Although The World appeared only posthumously, Descartes did reveal his cosmological views in his Principles of Philosophy (1644). In the third part of that work, which deals with the “visible universe,” he argued that Copernicus's theory not only explains phenomena much better than Ptolemy's but is also “a little simpler and clearer” than Tycho's (AT VIIIA 85, CSM I 250). Descartes adopted two strategies to protect himself against the risk of legal attack by either the Catholic or the Protestant church. The first consists in maintaining that strictly speaking the earth does not move (AT VIIIA 90, CSM I 252). Planets are in fact carried around by a vortex of subtle matter circling the sun, which means that they remain at rest in the surrounding medium (Garber 1992, 181–88). Second, Descartes resorted to “the standard subterfuge for astronomers and natural philosophers seeking to avoid trouble,” namely that of presenting his cosmological theory as a mere hypothesis (Finocchiaro 2005, 50–51). In spite of these prudential measures, Descartes was, however, regarded by contemporary readers as a “realist Copernican.” As shown by Schuster, the Principles offer a descriptive-explanatory narrative unifying his theories of vortices, magnetism, sunspots, stellar novae, and newly discovered variable stars, along with a theory of planet formation from dead, sunspot-encrusted stars. This tour de force amounts to the most daring and radical statement of a multistellar Copernican system to that date (Schuster 2013, 543–86).

Both in The World and in the Principles, Descartes puts forward a fictional account of the genesis of the universe, which he integrates with graphical representations of the solar system and with analogical explanations of the behavior of planets, stars, and comets. Chapter 6 of The World narrates how God initially divided matter into parts of different size and shape and caused them to move “in accordance with the ordinary laws of nature.”