Democritus (BC 400) and the “Atomists” debate the “four elements (fire, water, earth, and air). They conclude that an object could not be cut in half again and again indefinitely. They decided that sooner or later the object would become so small that it could not be divided again. They called this indivisible invisible particle an “Atom”. (Atom is the Greek work meaning “not to be cut” or “indivisible”).