French philosopher, mathematician and writer René Descartes has been called the father of modern philosophy. His Principia Philosophiae, first published in 1644, put forth the theory that the universe operated as a continuously running machine which God had set in motion. The universe, which has no vacuum, was composed of a 'subtle matter' he named 'tourbillons,' which swirled in vortices like whirlpools and actually moved the planets by contact.