瑜伽師地論略纂 5.55

5.55

論釋名中，但釋通名。　「前七解脫於已解脫生勝解」者，七所觀法要離彼地煩惱障染方始修作，名已解脫。今觀彼境為除定障，起神通功德，而生勝解，故名解脫。　「第八解脫棄背想受」者，前遠無間道雖滅想受障，今方得名解脫。正起解脫時，但暫棄背想受立解脫名，非時方始解脫定障，先已離故。

In the treatise's explanation of the names, it only explains the shared name. Regarding "The first seven liberations generate resolute intention regarding that from which one has already been liberated": the phenomena contemplated by the seven must be cultivated only after one has become free from the defilement of the affliction-obstacles of that bhūmi, which is called 'already liberated'. Now one contemplates those objects in order to eliminate the obstacles to concentration and generate the qualities of supernormal powers, thereby generating resolute intention; hence they are named 'liberation'. Regarding "The eighth liberation turns away from perception and feeling": although the prior, remote uninterrupted path extinguished the obstacle of perception and feeling, only now does it attain the name 'liberation'. When directly giving rise to the liberation, it is designated with the name 'liberation' simply by temporarily turning away from perception and feeling; it is not that only at that time does it first become liberated from the obstacles to concentration, because it had already become free from them earlier.