THE RENAISSANCE 125 



many a Greek philosopher. Descartes contrasts 

 matter anc spirit, and, since spirit is individual and 

 exists in personal units, matter must be continuous. 

 In a continuous, closely packed universe, movement 

 is only possible if it occur in closed circuits, every part 

 of which must move together. Hence Descartes 

 arrived at his famous theory of vortices, which for 

 twenty years reigned supreme, and contested for a 

 time even the Newtonian system, which the Cartesians 

 argued gave no explanation, since it depended on the 

 hypothesis of unknown and mysterious forces. 



Yet Descartes' physical ideas did good service to 

 science. Though barred by Protestant orthodoxy, 

 and put on the Catholic Index at the instigation of the 

 Jesuits, his works became the fashion. They offered 

 an explanation of the phenomena of the astronomical 

 universe by mechanical processes ; they banished 

 for ever Aristotle's distinction between the essential 

 nature of the sublunary sphere, which included the 

 earth, and the starry sphere beyond of incorruptible 

 and perfect heavenly bodies ; they made unnecessary 

 the animate being of Aquinas or the genii believed in 

 by Kepler as the cause of planetary motion. Whether 

 or no the Cartesian explanation stood, the solar 

 system was susceptible of physical treatment ; in 

 common words, the thing could be understood. 



Descartes spent most of his working lifetime outside 

 France, and seems to have been to a great extent 



independent of contemporary French 

 Pascal. . n . , , 



influences, such as that exercised by 



Montaigne or, at any rate, unconscious of them ; but 

 in another direction the sceptical attitude of current 



