 By the time Aristotle (4th century BCE) developed his discussion of the infinite, this concept had thus made its presence felt in philosophy, mathematics, and natural philosophy (including cosmology, astronomy, and physics). It would be hard to exaggerate the role played by Aristotle in the history of infinity. He articulated some essential conceptual distinctions that were to influence all subsequent discussions. He was a finitist in the sense that in his universe, everything is finite. The cosmos is finite, bodies are finite, geometrical segments are finite, each number is finite, etc. However, there are processes that can be iterated indefinitely, giving rise to what he called ‘potential infinity’. He claimed in fact that “in a sense [the infinite] is and in a sense it is not.” (Phys. 3.6, 206a13–14).