The closing reference to Heraclitus and Zeno compounds this point. Heraclitus is famous for saying that everything is fire, and that everything is constantly changing. One of his examples of this perpetual change is that one can never step into the same river twice: the actual water that makes up the river is constantly moving, and is constantly different. Zeno is famous for the paradox that bears his name, which can be formulated in a number of different ways. One method is to point out that to get to a certain point, one must first go half the distance to that point, and before that one must go half the distance to that halfway point, and so on. Because there is always a shorter, halfway distance between one's present location and one's destination, it is impossible to move at all. Thus, Zeno concludes, contrary to Heraclitus, that there is no change at all: motion is an illusion.
Heraclitus formulated his doctrine in response to earlier theories that tried to explain the universe in terms of certain static forces or elements. Heraclitus saw a dynamic universe, which he expressed vividly in his claim that everything is fire. Zeno took Heraclitus' perpetual change as a starting point, and tried to go further, ultimately concluding that change does not exist. Zeno, like the Hegelians, only understood his predecessor in a distanced, reflective manner. If he had had the passion truly to understand Heraclitus' point of view, perhaps he would have felt no need to move beyond it.