Parmenides of Elea (c. 515-450 B.C.E.), together with his two pupils, Zeno (c. 490–c. 430 B.C.E.) and Mellisus of Samos (fl. 440 B.C.E.), formed the Eleatic school. Parmenides had the compelling idea of uniting the ultimate primary substance of everything with our perceived reality that seems to be composed of many different things. He argued forcefully that reality is an undifferentiated whole that is unmoving and unchanging. Parmenides dismissed change and the many different things that human beings ordinarily experience as mere appearance and illusion.