大般涅槃經義記 8.152

8.152

六就實分別，十二因緣窮其本性，真心所起，如夢所作皆報心起，故《地經》說十二因緣皆真心作。真心即是如來藏性，古今常湛，清淨不變，何有因緣起作可得？所以非有。隨妄流轉，集起生死，說為非無。非有、非無，故名中道。又彼真心離性名為非有，體具法界恒沙佛法說為非無，非有、非無名為中道。

Sixth, discrimination in terms of the real: when exhausting the fundamental nature of the twelve links of dependent origination, they arise from the true mind, just as what is done in a dream all arises from the karmically resultant mind; hence the Daśabhūmika Sūtra states that the twelve links of dependent origination are all made by the true mind. The true mind is none other than the tathāgatagarbha nature, constantly serene from antiquity to the present, pure and unchanging; how could any arising or acting of dependent origination be found in it? Therefore it is non-existent. Flowing in accordance with delusion, it aggregates and gives rise to saṃsāra, so it is spoken of as not non-existent. Being neither existent nor non-existent, it is therefore called the middle way. Furthermore, that true mind being free from inherent nature is called non-existent; its essence possessing the buddha-dharmas as numerous as the sands of the Ganges in the dharmadhātu is spoken of as not non-existent. Being neither existent nor non-existent is called the middle way.