The central question of this thesis explores what the thought of Canadian Jesuit philosopher Bernard Lonergan may contribute to a Catholic perspective of environmental ethics. In comparison with secular environmental movements, Roman Catholicism has arrived relatively late on the scene to examine formally issues of specifically ecological import from either a theological or academic stance. Catholic ecotheology is still in its formation but offers much potential for effective collaboration among and between both Catholics and non-Catholics. As it stands, the great variety of issues at stake in environmental ethics calls for a multidisciplinary approach involving science, technology, politics, economics, law, education, philosophy, and religion. Finding common ground on which to discuss the issues and prioritize values proves difficult. This thesis explores ways that common ground may be sought both within Catholicism and in the broader secular sphere using Lonergan's three-fold notion of conversion (intellectual, moral, and religious conversion), his notions of the human good and collective responsibility, his method of self-appropriation, and his cognitional theory which claims invariance in the structure and process of knowing. Because the call for change, not just of social systems but also of hearts and minds, is a recurring theme in any environmental ethics, Lonergan's notion of conversion will be crucial to this exploration of common ground
