One major insight derived from the moral twin earth debate is that evaluative and descriptive terms possess different levels of semantic stability, in that the meanings of the former but not the latter tend to remain constant over significant counterfactual variance in patterns of application. At the same time, it is common in metanormative debate to divide evaluative terms into those that are thin and those that are thick. In this paper, I combine debates about semantic stability and the distinction between the thin and the thick by presenting a new seamless inferentialist account of thin and thick evaluative terms which, despite subsuming them under the same metasemantic analysis, can nevertheless account for their varying levels of semantic stability. According to this position of ‘seamless metaconceptualism’, thin and thick evaluative terms do not belong to different categories, but are both understood as metaconceptual devices which do not differ in kind, but in scope. By providing the same analysis for both thin and thick terms, seamless metaconceptualism not only entails that the latter cannot shoulder the philosophical work that some have attributed to them, but also removes much of their surrounding intrigue.
