 The most important argument Gelug advances for the unity of the two truths draws upon an understanding of the compatible relation between conventional truth and dependent arising on the one hand, and between ultimate truth and emptiness on the other. For Gelug emptiness and dependent arising are synonymous. The concept of emptiness is incoherent unless it means dependent arising, and equally the concept of dependent arising is incoherent unless it means emptiness of intrinsic reality. Gelug argues, as Tsongkhapa does in the Rten ‘brel stod pa (In Praise of Dependent Arising, 1994a), since emptiness means dependent arising, the emptiness of intrinsic reality and the efficacy of action and its agent are not contradictory. If emptiness, however, is misinterpreted as contradictory with dependent arising, then Gelug contends, there would be neither action in empty phenomena, nor empty phenomena in action. But that cannot be the case, for that would entail a rejection of both phenomena and action, a nihilistic view (v.11–12). Since there is no phenomenon other than what is dependently arisen, there is no phenomenon other than what is empty of intrinsic reality (v.15). Understood emptiness in this way, there is indeed no need to say that they are noncontradictory—the utter nonexistence of intrinsic reality and making sense of everything in the light of the principle this arises depending on this (v.18). This is so because despite the fact that whatever is dependently arisen lacks intrinsic reality, and therefore empty, nonetheless its existence is illusion-like (v.27).