Wang Chong (, 27–c. 100 AD), courtesy name Zhongren (仲任), was a Chinese philosopher active during the Han Dynasty. He developed a rational, secular, naturalistic and mechanistic account of the world and of human beings and gave a materialistic explanation of the origin of the universe. His main work was the Lùnhéng (論衡, "Critical Essays"). This book contained many theories involving early sciences of astronomy and meteorology, and Wang Chong was even the first in Chinese history to mention the use of the square-pallet chain pump, which became common in irrigation and public works in China thereafter. Wang also accurately described the process of the water cycle.