New Math
In his book, Why Johnny Can't Add: The Failure of the New Math, Morris Kline says that certain advocates of the new topics "ignored completely the fact that mathematics is a cumulative development and that it is practically impossible to learn the newer creations, if one does not know the older ones". He also noted the trend to abstraction in New Math. Kline says "abstraction is not the first stage, but the last stage, in a mathematical development".