This essay focuses on conceptual engineers who aim to improve other people's patterns of inference and attention by shaping their concepts. Such conceptual engineers sometimes engage in a form of epistemic paternalism that I call paternalistic cognitive engineering: instead of explicitly persuading, informing and educating others, the engineers non-consultatively rely on assumptions about the target agents’ cognitive systems to improve their belief forming. The target agents could reasonably regard such benevolent exercises of control as violating their sovereignty over their own (...) belief formation. This is a pro tanto reason against such engineering. In addition to the relevant projects of conceptual engineering, paternalistic cognitive engineering plausibly includes certain kinds of nudging and evidence suppression. I distinguish the sovereignty-based concern from other ethical worries about conceptual engineering and discuss how one might justify the relevant conceptual engineering projects despite the sovereignty-based reason against them. (shrink)