so what are the core things? some suggestions: - indirection - abstract data types - awareness / isolation of mutable state - choosing the time of evaluati

so what are the core things? some suggestions: - indirection - abstract data types - awareness / isolation of mutable state - choosing the time of evaluation what else? i am trying to get the fundamental, simple issues that underly "movements" or allow us to manage complexity (many gof "design patterns" seem to reduce to the above, for example). although i am not sure what movements encapsulate the above...