AAAS: COMMON THEMES: Constancy and Change - Things can change in detail but remain the same in general (the players change, but the team remains; cells are replaced, but the organism remains)
Things can change in detail but remain the same in general (the players change, but the team remains; cells are replaced, but the organism remains). Sometimes counterbalancing changes are necessary for a thing to retain its essential constancy in the presence of changing conditions.