金剛經纂要刊定記 2.69

2.69

中者。以假故非空，空故非假，非空非假、即空即假，名為中義。故《淨名》云：「說法不有亦不無，以因緣故諸法生。」又如《中論》都明有等四義，云：「因緣所生法，我說即是空，亦名為假名，亦名中道義。」即三乘教中所說，空有中假等義，並不出因緣。故云佛教統宗因緣也。

As for "the middle": Because it is conventional, it is not empty; because it is empty, it is not conventional. Being neither empty nor conventional, and being simultaneously empty and conventional, is called the meaning of the middle. Therefore the *Vimalakīrti* says: "The Dharma spoken is neither existent nor non-existent; / by causes and conditions all phenomena arise." Furthermore, as the *Madhyamaka-śāstra* comprehensively clarifies the four meanings including existence, saying: "Whatever phenomenon is produced by causes and conditions, / that I declare to be precisely śūnyatā; / it is also termed conventional designation, / and is also the meaning of the middle way." Thus the meanings of emptiness, existence, the middle, conventional designation, and so forth spoken in the teachings of the three vehicles do not go beyond cause and condition. Therefore it says that the Buddhist teachings universally take cause and condition as their central doctrine.