Is this just a dream? Daoist philosopher Zhuang Zi and metaphysician Descartes both considered this question but came to very different conclusions. In his Dream Hypothesis, Descartes imagined that all of his beliefs about the external world could be mistaken, which led him to the realization that the only thing that he could be certain of was his own existence: “I think therefore I am.” But what am “I”? “I am a thinking thing”, he said and concluded that the existence of one’s mental self is clear, certain and indubitable, while the existence of a physical world was open to doubt. Zhuang Zi, in a similar vein, dreamt that he was a butterfly, and, on awakening, could not be sure that he was not a butterfly dreaming that he was a man. Rather than drawing a distinction between dreams and reality, or between certainty and dubitability, however, he concluded that our identities, like everything else in the world, are fluid and subject transformation and transmutation. The very different treatments of the dream scenario by these two thinkers stem from fundamentally different assumptions embedded in the two philosophical traditions. Analyzing them side by side, we realize how the resources of each intellectual tradition cast light on the unquestioned assumptions underlying the philosophy of the other. This cross cultural engagement highlights the ways in which these two varieties of skepticism fall short of complete, universal skepticism and potentially points the way towards a synthesis of the resources of Western rationalism and philosophical Daoism that may lead to novel formulations of radically skeptical world views.