Threshold concepts: Tensions and truths

Abstract Since their introduction, threshold concepts have served as a framework for understanding the transformative nature of learning across different disciplines. Although threshold concepts framework is a relative newcomer in the teaching and learning space, two decades of research have exposed persistent debates about the theoretical coherence of threshold concepts and critiques about their application. Critics point to the “conceptual fuzziness” of the framework, leading to calls to abandon threshold concepts in favor of less ambiguous models. The purpose of threshold concepts is also debated—should educators aim to redesign curricula to smooth the learner’s journey by eliminating these “stuck places” or should these thresholds be purposefully fortified as essential sites of productive struggle? This paper serves to address these debates head-on, and in doing so argues that the ambiguity of threshold concepts is not a theoretical flaw, but an accurate reflection of the complex, non-linear nature of deep and transformative learning. To operationalise this complexity, we introduce the uncertainty tolerance (e.g., individual’s responses to unknowns across cognitive, emotional and behavioural domains) conceptual framework as a robust mechanism for distinguishing true, identity-shaping thresholds from simply ‘troublesome’ knowledge. While threshold concepts share theoretical DNA with Transformative Learning, Situated Learning, and Boundary Crossing, the lens of uncertainty tolerance uniquely illuminates how learners navigate the “liminal space” where old conceptions are discarded and new identities are formed. Consequently, we argue that the goal of curriculum design is not the elimination of thresholds, but the strategic identification of these junctures to scaffold learner resilience. By viewing threshold concepts through the lens of uncertainty, educators can move beyond binary definitions of success, reframing thresholds from obstacles to be removed into recursive, necessary gateways for professional identity formation. Ultimately, we assert that the framework of threshold concepts is itself a threshold concept: troublesome, liminal, and irreversibly transformative for the educator once embodied.