Abstract
Aristotle's discussion of time is part of his Physics, which was an important part of the philosophical curriculum of late antiquity. Aristotle says that it is because nature is a principle of change that people must establish what change is. This chapter focuses on his scientific treatment of time. Aristotle begins his discussion of time by engaging in the examination of a set of puzzles (aporiai). He clearly indicates that this examination is embedded in the two‐stage inquiry. Aristotle develops, within his positive account of time, the conceptual tools to deal with a puzzle. The chapter shows how the definition of change advanced in the third book of the Physics contributes to the discussion of time developed in the fourth book.