維摩經玄疏 3.91

3.91

一、明所詮理者，即是一諦理也。何等名為一諦？「諦」名審實，審實之法，即是不二。豈是三諦、二諦皆名審實！今明真、俗說為諦者，但是方便，實非諦也。故《涅槃經》云：「所言二諦，其實是一。如來方便，為化眾生，故說為二。」譬如日月不轉，醉人見轉。當知唯有不轉之日，不醉之人同見，豈別有迴轉之日！若實有轉日者，不醉之人亦應竝見也。一諦如真日，二諦如轉日，真日審實，可名一諦；轉日不實，何有二諦！方便說二，實義不成，故非諦也。今以此一實諦，為所詮之理也。

First, clarifying the principle expressed [means] the principle of the one truth. What is called the "one truth"? "Truth" means critically discerned as real; what is critically discerned as real is non-dual. How could three truths or two truths all be called critically discerned as real! Now clarifying that the ultimate and conventional are spoken of as truths is merely an expedient, not genuinely a truth. Thus the Nirvāṇa Sūtra says: "What is spoken of as two truths is in fact one. The Tathāgata, as an expedient to transform sentient beings, therefore spoke of them as two." For instance, the sun and moon do not revolve, yet a drunkard sees them revolving. One should know that there is only the non-revolving sun, which all sober persons see alike; how could there be a separate revolving sun! If there were genuinely a revolving sun, sober persons should also see it. The one truth is like the true sun; the two truths are like the revolving sun. The true sun is critically discerned as real and can be called the one truth; the revolving sun is not real, so how could there be two truths! Being spoken of as two is an expedient; its real meaning is unestablished, hence it is not a truth. Here we take this one real truth as the principle that is expressed.