When Henry Jekyll declares that “man is not truly one, but truly two”, he is quick to add that his knowledge of human nature is actually incomplete, and that he guesses that “man will be ultimately known for a mere polity of multifarious, incongruous and independent denizens”. Jekyll’s vision of nature is thus, on the one hand, deeply dualistic; and, connected to this, his idea of science is built on separation and control, the trademarks of a positivist scientist. On the other hand, he suggests the existence of a wilder, more chaotic understanding of human nature than the one his science (and his biases) can grasp. If his dream of separating “the two natures” in himself, which he identifies as good and evil, morality and the body, has catastrophic results, would embracing this ill-defined, non-dualistic conception of human nature lead to better results? Rather than guiding his reader towards a simple solution, Stevenson ambiguously leaves his readers with the task of questioning their own conception(s) of nature and of the natural.