宗鏡錄 62.10

62.10

問。欲色二界。有外器色境。云是心變故。所言唯心。且如無色界天。唯有內心。無外色境。何要更言唯心。豈不成相扶極成過。

Question: In the desire and form realms, there are external material objects of the receptacle realm, and because these are said to be transformations of citta, one speaks of mind-only. But in the case of the gods of the formless realm, there is only inner citta and no external material objects. Why is it necessary to speak of mind-only there as well? Would that not commit the fallacy of proving what is already established (siddhasādhana)?