This article explores the cognitive aspects of utopia in environmental and sustainability education. Utopia here is understood as the imaginary transformation of society, entailing a critique of society and its imaginary reconstruction aligned with the ideal of just and flourishing communities. To gain insight into the processes at play, I develop a pragmatist semiotic framework and highlight five characteristics of utopia in the context of environmental and sustainability education: "dystopia," "modifications," "existing beliefs," "transfer of concepts," and "missing alternative concepts." At the core of these features are two other phenomena--dissonance and vagueness--that can serve as a springboard for extended exploration and a deeper understanding of society, as well as of held beliefs and ideals. When working with utopia, I conclude that students themselves may become minimal utopian spaces. This process may be accompanied by adverse feelings, such as confusion, frustration, or anxiety, which implies that working with utopia as a means to empower learners may also make them vulnerable.