Fifty years ago, envisioning the land ethic, Leopold lamented, "The proof that conservation has not yet touched these foundations of conduct lies in the fact that philosophy and religion have not yet heard of it."

      Well, they have now. Today, two dozen anthologies and two dozen systematic works in environmental ethics have been published Courses are taught in several hundred universities and colleges There are four professional journals in the field The International Society for Environmental Ethics (ISEE) has four hundred members in twenty countries. The website bibliography of the ISEE contains over seven thousand articles and books by philosophers and many others with an ethical concer n about human relations to the natural environment.

      If someone had been attempting to foresee the future of philosophy at mid-century, perhaps the two most surprising developments would have been the rise of environmental philosophy and the novel perspectives introduced by feminists, including ecofeminists. The next most surprising might well be the interest in animal welfare and in international development ethics, both of which have ties to environmental philosophy.

      Environmental ethics remained unknown in philosophy until the mid-1970's, but that was to change rapidly. Philosophers have thought about nature for millennia, since ancient Greece, as well as in Asia. There is an ethic implicit in many of these worldviews but that was never really developed as an environmental ethics. Following the philosophical enlightenment and the scientific revolution in Europe, nature came to be regarded as a value-free realm, governed by mechanistic causal forces. Values in nature arose only with the interests and preferences of humans. For four centuries, Western philosophy was dominantly humanistic or anthropocentric. People were what counted and all that counted in ethics.

      Leopold insisted that ethics goes further than prudential natural resource use, however much this must figure within it. This new ethic enlarges traditional ideas about what is of moral concern to include animals, plants, endangered species, ecosystems, and even Earth as a whole. Such ethics is unique in moving outside the sector of human interests, including human interests in this larger community of life. Leopold gave us, famously, a new commandment: "A thing is right when it tends to preserve the integrity, stability, and beauty of the biotic community. It is wrong when it tends otherwise."

      Somewhat ironically, in the century when humans, with their increasing industry and technology, seemed further and further from nature, the natural world emerges as a focus of ethical concern. Ironically as well, philosophers have to thank Leopold, a forester, for launching this ethics (with other prophets like Rachel Carson, John Muir, or David Brower).

      Leopold never faced many of the issues now paramount in environmental ethics. Ecosystems have proved more complex than he thought; and we are reconsidering their integrity and dynamic historical changes. The human power to affect nature has dramatically escalated. Industrialization, advanced technologies, global warming, global capitalism, consumerism, and exploding populations raise new concerns; but this is unfolding a movement that Leopold launched.

      Once, yes, philosophers had never heard of environmental ethics. Today I doubt that one could find any philosopher in the land who has not heard of it. Thousands of philosophers recognize this as among the urgent concerns on our ethical agenda, and Leopold would have been pleased to have this as part of his legacy.

      Holmes Rolston, III is professor of philosophy, Colorado State University, and the author of Biology, Ethics and the Origins of Life.

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