We conducted a qualitative analysis of 5 years of student writing data to understand learning and moral development on a field philosophy course in Isle Royale National Park. We were interested in the connection between physical experiences in the natural world and the way students care about or value nonhuman beings, natural systems, and place. Students consistently demonstrated a shift from a dualistic to a more complex understanding of ideas, relationships, and the natural world. This widening perception and moral awareness occurred in tandem with course content learning. In this paper we describe the model that emerged from our data to describe this shift from dualism to complexity--from self-awareness, to social learning, to curriculum engagement, to a wider moral community--and the factors that facilitate each step. We also provide a planning and assessment tool to help other educators begin to observe ethical development and relational growth in their own interdisciplinary environmental field classes.