"One always swims in the same river, one never sits down on the
same bank. The fluvial basin is stable in its flux... As a system
open to evaporation, rain, and clouds,
it always...brings back the same water... The fluid is stable;
the solid which wears away is unstable - Heraclitus and Parmenides
were both right. Hence the notion of homeorrhesis." --Michel Serres