This initial consideration of the simplest relations of our ideas already causes us to recognize the necessity of Descartes's vortexes; that their number will increase in proportion as the rectilinear motions of all the parts of extension, having been more opposed to each other, will have had greater difficulty accommodating the same motion; that of all these vortexes, the largest will be those wherein more parts have tended toward the same motion, or whose parts have had more power to continue their rectilinear motion.