Global mental health research is increasingly highlighting the high levels of untreated mental illness in Africa and calling for the scaling-up of services in order to redress this situation. A particular model of care is being strongly advocated for such scale-up, and a recent explosion of research is providing guidelines for its implementation. This article seeks to open up the 'black box' of international research on scaling up the provision of mental health care in Africa, unearthing the hidden assumptions and power dynamics underpinning the knowledge produced. It insists that gaining a better understanding of care provision demands that we not only fill the gaps in knowledge but also problematize the assumptions upon which existing knowledge is based. This article demonstrates how two interrelated paradigms are strongly mediating research in this area - those of 'scientific evidence' and 'human rights'. Drawing on recent research within the sociology of scientific knowledge, and strands of postcolonial thought, it demonstrates how these paradigms are both underpinned by several contentious epistemological assumptions, assumptions which are deeply inserted within the epistemological order of Western modernity. The main argument is that through their shared ideological undertones of 'objectivity', 'universalism' and 'rationalism', these paradigms are potentially marginalizing other possibly important ways of thinking about care in Africa, ways which might not originate from modernist forms of consciousness. This article makes a plea for a more inclusive and plural archive of knowledge on scaling up mental health care in Africa, one which is more hospitable to diverse epistemological politics and moral landscapes.