The constant flux and caprice of mental events do not admit of the establishment of stable experimental conditions. Hermann Ebbinghaus
"The city" is not a framework but a social practice in constant flux the more it becomes an issue, the more it is a source of contradictions and the more its social manipulation is linked to the ensemble of social and political conflicts. Manuel Castells
Of course, a movie is in constant flux. W. D. Richter
An ecosystem is more like a conference than a community -- indefinite, pluralistic, tolerant, and in constant flux. Kevin Kelly (editor)