大乘起信論別記 1.91

1.91

The statement "If separated from non-enlightenment, there is no self-characteristic of true enlightenment that can be expounded" explains that the expounded true enlightenment necessarily depends on non-enlightenment; if they did not depend on each other, there would be no self-characteristic. What exists in dependence on another also has no self-characteristic; since the self-characteristic is absent, how could there be the characteristic of another? This reveals that all dharmas are ungraspable. As the text below says: "One should know that all defiled dharmas and pure dharmas are mutually dependent, having no self-characteristic that can be expounded." The Mahāprajñāpāramitopadeśa says: "If the conventional truth were real even to the slightest degree, the ultimate truth would also have to be real." This is what it means.