This article was inspired by participant observation of a contemporary collaboration between empirically oriented philosophers of mind and neuroscientists. An encounter between this anthropologist of science and neurophilosophers in a Finnish sleep laboratory led to the following philosophical exploration of the intellectual space shared by neurophilosophy and science studies. Since these fields emerged in the 1970s, scholars from both sides have been visiting brain research facilities, but engaged with neuroscientists very differently and passionately fought with each other over the reduction (...) of mind to brain. As a case in point, this article looks at the philosophical controversy over the dreaming brain. It serves as a window on the problem space opened up by the demise of positivist conceptions of science, now inhabited by both neurophilosophy and science studies. Both fields face the problem of how to bridge the gap between empirical research and conceptual work. At a time when ontological speculation has made a comeback in these areas of research, studies on how epistemic objects manifest themselves in the material culture of neuroscience could help neurophilosophers to become better materialists. In the sleep laboratory, however, the materiality of dreams continues to be elusive. In dreaming science studies and neurophilosophy encounter a phenomenon that – at least in 2015 – still invites a positivist rather than a materialist attitude. (shrink)