All the more so since wherever the dead go, they do not come back--no-one can be sure whether their ancestors have gone to the Pure Land to cultivate themselves. Otherwise, if the ancestors have already given up desire, selfishness and attachment, why would one need to keep bothering them with ancestor worship ceremonies?
更何況那是個去了就沒人回來的地方，誰也無法確定祖先真的去了淨土修行，否則祖先已無慾無我的看破執著，人們又何必三不五時燒香祭祖、加以打擾？