In medical education, we assess knowledge, skills, and a third category usually called values or attitudes. While knowledge and skills can be assessed, this third category consists of ‘beetles’, after the philosopher Wittgenstein’s beetle-in-a-box analogy. The analogy demonstrates that private experiences such as pain and hunger are inaccessible to the public, and that we cannot know whether we all experience them in the same way. In this paper, we claim that unlike knowledge and skills, private experiences of medical learners cannot be objectively measured, assessed, or directly accessed in any way. If we try to do this anyway, we risk reducing them to knowledge and skills—thereby making curriculum design choices based on what can be measured rather than what is valuable education, and rewarding zombie-like student behaviour rather than authentic development. We conclude that we should no longer use the model of representation to assess attitudes, emotions, empathy, and other beetles. This amounts to, first of all, shutting the door on objective assessment and investing in professional subjective assessment. Second, changing the way we define ‘fuzzy concepts’ in medical education, and stimulating conversations about ambiguous terms. Third, we should reframe the way we think of competences and realize only part of professional development lies within our control. Most importantly, we should stop attempting to measure the unmeasurable, as it might have negative consequences.