Zeno of Elea was an ancient Greek philosopher who lived in the 5th century BCE. He is best known for his paradoxes, which were used to challenge accepted ideas about space and time. He is also credited with inventing the reductio ad absurdum method of argumentation. Zeno's most famous paradox is the Dichotomy Paradox, which states that motion is impossible because an object must first traverse half the distance before it can traverse the other half.