The Pluralist school was a school of pre-Socratic philosophers who attempted to reconcile Parmenides' rejection of change with the apparently changing world of sense experience. The school consisted of Anaxagoras, Archelaus, and Empedocles. It can also be said to have included the Atomists, Leucippus and Democritus. The Pluralists rejected the idea that the diversity of nature can be reduced to a single principle (monism). Anaxagoras posited that nature contained an innumerable number of principles, while Empedocles reduced nature to four elements (fire, air, earth, and water) which could not be reduced to one another and which would be sufficient to explain change and diversity.