Zeno of Elea (; Ancient Greek: Ζήνων ὁ Ἐλεᾱ́της; c. 490 – c. 430 BC) was a pre-Socratic Greek philosopher. He was a student of Parmenides and one of the Eleatics. Born in Elea, Zeno defended his instructor's belief in monism, the idea that only one single entity exists that makes up all of reality. He rejected the existence of space, time, and motion. To disprove these concepts, he developed a series of paradoxes to demonstrate why these are impossible. Though his original writings are lost, subsequent descriptions by Plato, Aristotle, Diogenes Laertius, and Simplicius of Cilicia have allowed study of his ideas. Zeno's arguments are divided into two different types: his arguments against plurality, or the existence of multiple objects, and his arguments against motion. Those against plurality suggest that for anything to exist, it must be divisible infinitely, meaning it would necessarily have both infinite mass and no mass simultaneously. Those against motion invoke the idea that distance must be divisible infinitely, meaning infinite steps would be required to cross any distance. Zeno's philosophy is still debated in the present day, and no solution to his paradoxes has been agreed upon by philosophers. His paradoxes have influenced philosophy and mathematics, both in ancient and modern times. Many of his ideas have been challenged by modern developments in physics and mathematics, such as atomic theory, mathematical limits, and set theory. Source: Wikipedia (en)