The intensified call for value pluralism within research on valuation in environmental decision-making responds to the recognition that neoclassical economic approaches to environmental valuation do not sufficiently account for important aspects of human–nature relations. However, few studies have explored how value plurality actually plays out in social deliberative reasoning and decision-making in practice, and these studies have mostly been deductive and quantitative. In his essay ‘Are choices trade-offs?’ Alan Holland (2002) goes to the heart of differences in conceptions of value and rationality between neoclassical and ecological economics. These conceptions differ in terms of whether values are seen as commensurable or incommensurable, whether people's choices amount to willing exchanges of gains and losses between different values and whether unwillingness to trade values off for net gain is irrational. Addressing Holland's question, we present a quasi-experimental study on deliberative valuation of marine issues on the Swedish west coast, where we considered how local citizens and politicians approached values in their reasoning and choice-making. Mixing quantitative and qualitative empirical material, we used an abductive analytical approach, iterating between data and theory to link our observations and interpretations to prevalent understandings of value, valuation and deliberation in the literature. The results demonstrate the relevance of value pluralism for environmental policy by showing the prevalence of preference uncertainty and intrapersonal value conflicts in participants' reasoning and interaction. Value conflicts played out as the inability to achieve multiple transcendental values that participants aspired to, including conflicts between social and environmental goals. Rather than attempting to commensurate different value dimensions, participants sought to avoid moral conflicts, showed emotional anguish when value conflicts came to the fore and tried to bridge conflicting aspirations and experiences through inclusive reason-giving and compromise. Thus, choices were not resolved through rational trade-offs, supporting Holland's claim and challenging the neoclassical trade-off model of choice. Incommensurability appeared as deliberate positions grounded in participants' experiences rather than as irrationality. Legitimately resolving value conflicts thus demands reason-sensitive means for deciding upon the sacrifices to be made and supporting public participation in environmental decision-making in ways that reveal peoples' actual moral considerations. Read the free Plain Language Summary for this article on the Journal blog.