Epistemic trust as a mechanism for ethics integration: failure modes and design principles from 70 moral imagination workshops

Bottom-up responsible innovation initiatives aim to empower technology development teams to engage in ethical reflection, yet such interventions frequently fail to achieve practitioner engagement. This paper proposes epistemic trust -- the degree to which practitioners regard an intervention, its facilitators, and its content as credible -- as a conceptual model linking intervention design to engagement. Drawing on philosophical work on testimony and practice-based qualitative analysis of over 70 moral imagination workshops with engineering teams between 2019 and 2025, we identify five dimensions of epistemic trust (Relevance, Inclusivity, Agency, Authority, and Alignment) and present a typology of 24 failure modes that arise when these dimensions are inadequately addressed. We derive nine design principles for cultivating epistemic trust, grounded in our operationalization of moral imagination through technomoral scenarios and structured deliberation. Our findings contribute to the literature on collaborative socio-technical integration by specifying the conditions of uptake that existing frameworks leave undertheorized.