“There are variations in the quality of deviation; not all divergence from the past is culturally significant. Any attempt to vary from the past in such a way as to cut the past off, causing it to be forgotten, has little cultural importance. Greater significance attaches to those variations that bring the tradition into view in a new way, allowing the familiar to be seen as unfamiliar, as requiring a new appraisal of all that we have been—and therefore of all that we are.”