Parmenides spent most of his time in Elea (Greek city-state in Southern Italy). He was born about 515 BCE. Parmenides is supposedly the first philosopher to deal with the philosophical subject of ontology. He argued that if one can think of something then it is part of being and if something is part of being then it can be thought of, but what does not exist cannot be thought of and what cannot be thought of does not exist. Pamenides asserted that there is no movement or change in the universe because the universe is one unified, eternal Being. Everything is really part of this one unchanging whole so that Being is really undivided.