This famous saying means that the water in the river is constantly flowing. This time you stepped into the river and the water ran away. Next time you step into the river, new water will flow. The river keeps flowing, so you can't step into the same river. Heraclitus' famous saying shows that objective things are always moving. Such a changing and developing truth. Obviously, this famous saying has its specific meaning, not the difference between this river and that river. Heraclitus advocated "the movement of all things" and "the flow of all things", which made him an outstanding representative of the "mobile school" with simple dialectical thought at that time.