The Eleatic Stranger, before proceeding to the final definition of sophistry, has to make clear the concepts that he used throughout the procedure of definition. In other words, he has to clarify what is the nature of the Being ("that which is"), Not-Being, sameness (identity), difference, motion (change), and rest, and how they are interrelated. Therefore, he examines Parmenides’ notion in comparison with Empedocles and Heraclitus’ in order to find out whether Being is identical with "change" or "rest", or both.