首楞嚴義疏注經 8.239

8.239

True cognition is unique, hence called 'sameness'; conventional cognition is differentiated, hence called 'difference'. The operational marks of the two cognitions, true and conventional, are mutually contradictory; bringing them into harmony so that they are neither identical nor different is why it is said 'cannot reach'. It is exceedingly superior, with none surpassing it, hence called 'Difficult to Conquer'. On this ground, one realizes the tathatā of undifferentiated species, meaning that this tathatā is not like the eyes and so forth, which have distinct categories; one severs the hindrance of lower vehicle nirvāṇa and cultivates the dhyāna-pāramitā to supreme excellence.