俱舍論記 8.28

8.28

「或心心所唯互相依」者，論主以理復難。若言無色同分、命根互相依者，或無色界心、心所法唯互相依，非須別依。又解：彼因既勝，心、心所法應唯互相依。如是所難方便，欲明同分、命根非實有體。

"Or mind and mental factors rely solely on one another" is the author of the treatise objecting further through reasoning. If you say that generic similarity and the life faculty in the formless rely mutually on one another, then alternatively, mind and mental factors in the formless realm rely solely on one another, without needing a separate support. Another explanation: Since their cause is superior, mind and mental factors should rely solely on one another. The purpose of this objection is to show that generic similarity and the life faculty do not have real substantial entities.