Within the Sanlun understanding, ultimate reality and conventional reality are articulated through the doctrine of the two truths, yet these are not two separate worlds. Ultimate reality is emptiness, the absence of inherent, independent self-nature in all dharmas, and it is not a hidden substance or realm standing behind appearances. Conventional reality is the realm of everyday distinctions and practical functioning, where phenomena arise dependently and are designated through language and concepts. The same phenomena, when viewed as dependently arisen and conceptually imputed, are called conventional truth; when examined as empty of own-being, they are called ultimate truth. Thus, the two truths are distinct as modes of understanding, but they refer to one and the same field of experience.

Sanlun thought stresses that ultimate reality is not found apart from conventional appearances; the ultimate truth about conventional things is precisely their emptiness. Emptiness is the true nature of conventional reality, and conventional reality is the manifestation of emptiness, so neither can stand alone. To say they are absolutely different would reify some permanent ultimate apart from the changing world, while to say they are simply identical would collapse the subtlety of emptiness into mere appearance. Their relationship therefore transcends both identity and difference, expressing a non-dual vision that avoids both eternalism and nihilism.

This vision has important implications for practice and understanding. Without the conventional—language, concepts, ethical distinctions, and daily activities—there would be no way to express or realize ultimate truth. Yet without insight into emptiness, conventional reality is easily mistaken for something solid and self-existing, leading to clinging and confusion. Sanlun masters therefore affirm the practical efficacy of conventional truth, while simultaneously showing that both truths themselves are empty of inherent existence. Enlightenment, on this view, is not escape to another realm, but the realization, in the midst of ordinary life, that emptiness and conventional appearance are inseparable aspects of a single reality.