There are two distinct strands within modern philosophical ethics that are relevant to environmental philosophy: an empiricist strand that seeks a naturalist account of human conduct and a humanist strand rooted in a conception of transcendent human freedom. Each strand has its appeal, but each also raises both strategic and theoretical problems for environmental philosophers. Based on a reading of Kant's critical solution to the antinomy of freedom and nature, I recommend that environmental philosophers consider the possibility of a Darwinian (...) humanism, through which moral agents are understood as both free and causally intertwined with the natural world. (shrink)