54．It has lived because readers appreciate a refreshing stimulus，an irreverent reminder that theylived in a world of platitudinous thinking, cheap moralizing, and foolishphilosophy．

(that引导的从句作reminder的同位语)

它之所以存在，是因为读者欣赏它使人耳目一新的刺激，它毫不客气地提醒：他们活在一个充满陈腐思想、廉价的道德说教与荒谬哲学的世界里。

分句1：it has lived…

分句2：because readers…

分句3：that they lived…

1和2为并列

2和3为嵌套