中觀論疏 10.40

10.40

「名色增長故」下，第五六入支。六入支即是六根。謂六根生六識，為識所入之處也。數云：六根能發於識，名之為入。發者是根之功能，六者是數名也，故六入一支就數及功能兩義。得名色增長生於四根故有五入，名增長故有意入也。

"Because name-and-form increases" and so forth: this is the fifth, the link of the six sense bases (ṣaḍāyatana). The link of the six sense bases refers precisely to the six sense faculties. That is, the six sense faculties produce the six consciousnesses and are the places into which consciousness enters. The Sarvāstivādins say: The six faculties can initiate consciousness, which is named "entering" (āyatana). Initiating is the function of the faculties, and "six" is the name of their number; therefore the single link of the six sense bases encompasses both meanings of number and function. Through the growth of form, the four faculties are produced, hence there are five sense bases; through the growth of name, there is the mental sense base.