Albert Schweitzer (1875-1965) preached a message of reverence for life - all life - that touched the hearts of a generation. As a medical doctor in French Equatorial Africa who selflessly helped those in need, Schweitzer was recognized with the Nobel Peace Prize in the wake of two world wars. But less than fifty years since the time of his death, the great humanitarian and scholar has faded from public awareness. In The New Rationalism, David Goodin explores the underlying philosophy behind Schweitzer's ethic of compassion, presenting it as a response to contemporary questions in social justice, economic equality, and environmental action. For the first time, the political, sociological, and philosophical contexts supporting the development of Schweitzer's ethic are examined in order to bring his timeless message of elemental morality to new life for the modern world. Inspired by Arthur Schopenhauer and Friedrich Nietzsche, Schweitzer built his ethic to create an elemental nature philosophy compatible with empirical science, and to support a new ontological understanding of the human person - a project he termed the New Rationalism. Goodin recovers and analyses Schweitzer's arguments and shows where his theories can provide a framework for both environmental and civic ethics today.