彰所知論 2.30

2.30

The four formless states: when cultivating the preparatory practice, because one contemplates infinite space, infinite consciousness, and nothingness, at the time of correct concentration one eliminates form and relies on the remaining four aggregates. The name of the fourth: because its perception is faint and obscure, meaning ignorance is predominant, it receives the name 'neither perception'; yet having faint and obscure perception, it is called 'nor non-perception'. In this order: the base of infinite space, the base of infinite consciousness, the base of nothingness, and the base of neither perception nor non-perception are called the four formless states. If cessation attainment is added, they are also called the nine progressive attainments.