In China, Xiong Shili 熊十力 is typically regarded as one of the most important Chinese philosophers of the twentieth century. The focus of this paper is Xiong’s monistic ontology and draws its findings principally from the 1932 literary edition of his New Treatise on Nothing but Consciousness. Xiong’s New Treatise is the first substantive attempt to respond to the modernist challenge of providing Chinese philosophy with ‘system,’ and he did this in the form of an ontology. The New Treatise consists of an interpretive summary and discussion of key Yogācāra teachings that feature in Cheng weishi lun; a sustained critique of views Xiong attributes to the sixth-century Yogācāra master Dharmapāla; and a synthesis of Yogācāra thought with ideas derived from Madhyamaka Buddhism, various Sinitic traditions of Buddhism, the Book of Change, Laozi and Zhuangzi, and from Chinese Neo-Confucian thinkers associated with the Lu-Wang wing of Neo-Confucian philosophy, as well as Zhu Xi. Xiong was very much a syncretist. I seek to explain why Xiong insisted that reality cannot be sought independent of phenomena despite his also claiming that phenomena are not real. The first and major part of the paper introduces Xiong’s critique of Yogācāra accounts of consciousness. The second part introduces his understanding of the doctrine of emptiness. I also trace the connection between Xiong’s understanding and how the concept of emptiness was understood in Tathāgatagarbha school of Sinitic Buddhism. I do not address the Confucian elements in his thought—the Buddhist elements are complex enough.