唯識二十論述記 1.69

1.69

述曰：為諸愚夫不知心外無實境相，便執實有，起諸惡業、二重障等。經說唯心，遮離心外遍計所執實境是有。不為遣除依他起性，不離於心、諸心所法。心為主故，說唯有心，理實亦唯有諸心所。

The Commentary states: Because foolish worldlings do not know that there are no real objective aspects outside the mind, they cling to them as real and generate evil karma, the two heavy obscurations, and so on. The sūtras speak of "mind-only" to exclude the existence of real objects conceptualized by imaginary construction outside the mind. It is not to eliminate the dharmas of mental factors that are of dependent nature (paratantra-svabhāva) and not separate from the mind. Because mind is principal, it says there is only mind; in truth there are also solely mental factors.