What, if any, are the limits of human understanding? Epistemic pessimists, sobered by our humble evolutionary origins, have argued that some parts of the universe will forever remain beyond our ken. But what exactly does it mean to say that humans are ‘cognitively closed’ to some parts of the world, or that some problems will forever remain ‘mysteries’? In this paper we develop a richer conceptual toolbox for thinking about different forms and varieties of cognitive limitation, which are often conflated (...) by the so-called ‘new mysterians’. We distinguish between representational access and imaginative understanding, as well as between different modalities of cognitive limitation. Next, we look at tried-and-tested strategies for overcoming our innate cognitive limitations, drawing from the literature on distributed cognition and cognitive scaffolding’. This allows us to distinguish between the limits of bare brains vs. scaffolded brains. Most importantly, we argue that this panoply of mind-extension devices is combinatorial and open-ended. In the end, this allows us to turn the table on the mysterians: for every alleged ‘mystery’, they should demonstrate that no possible combination of mind extension devices will bring us any closer to a solution. (shrink)