When the study of the household (ecology) and the management of the household (economics) can be merged, and when ethics can be extended to include environmental as well as human values, then we can be optimistic about the future of humankind. Accordingly, bringing together these three ‘E's' is the ultimate holism and the great challenge for our future.
Eugene Pleasants Odum (1993). “Ecology and our endangered life-support systems”