Which Pre-Socratic philosopher is famous for the statement that one cannot step into the same river twice?

Heraclitus is renowned for the idea that one cannot step into the same river twice, which encapsulates his belief in the constant change and flux of the universe. This statement represents his philosophical view that everything is in a state of perpetual transformation. Heraclitus emphasized that reality is not static, and even seemingly identical experiences are different upon each encounter, much like flowing water in a river. This fundamental principle of change contrasts sharply with more static perspectives of other Pre-Socratic philosophers who focused on the elements or the underlying substance of reality. Heraclitus's assertion also highlights the interconnectedness of change and identity, stressing that while many things remain consistent in form, their essence and nature are continuously evolving. This perspective has influenced various philosophical discussions on identity, time, and existence throughout the ages.