大乘起信論裂網疏 5.15

5.15

此即計斷滅空之外道也。執此唯空無物境界以為涅槃真如，故滅色歸空，得四空定，謂我已證涅槃真如。由其人我見在，所以窮空不歸，便入輪轉。

This refers to the non-Buddhists who calculate an annihilatory emptiness. Clinging to this state of being merely empty and devoid of anything as nirvāṇa and tathatā, they extinguish form to return to emptiness and attain the four formless concentrations, claiming, 'I have realized nirvāṇa and tathatā.' Because their view of a personal self remains, they exhaust emptiness without returning and then enter cyclic existence.