In
the Preface to the last collaborative effort of this kind, the Literary History of the United States(1948), Robert E.Spiller and his co-editors declared that “each generation
should produce at least one literary history of the United States, for each generation must define
the past in its own terms.” Earlier, just after World War I, the editors for
the Cambridge History of American
Literature had made much the same point.1) In
fact, however, the 1948 literary history has stood for nearly forty years, leading its editors to observe in the
1974 edition that their work had belied their “original pronouncement that ‘each
generation must define the past in its own terms.”

in fact之后這句話什么意思?