Although Aldo Leopold recognized the significance of ecology much earlier, calling it "the outstanding discovery of the twentieth century," it was not until the 1960s with the rise of the Age of Ecology that the wider public became aware of the science of ecology and its relevance to environmental matters. During that period the foundations were laid for a religious and philosophical revolution of the first magnitude. As G. Tyler Miller observed: "The ecological revolution will be the most all-encompassing revolution in the history of mankind." Warwick Fox added that deep ecologists were contributing to "a 'paradigm shift' of comparable significance to that associated with Copernicus." That new philosophical challenge was directed at the pervasive metaphysical and ethical anthropocentrism that has dominated Western culture with classical Greek humanism and the Judeo-Christian tradition since its inception. ' It is generally acknowledged that Rachel Carson's Silent Spring ushered in what can appropriately be called the Age of Ecology. Her attack on pesticides coincided with increasing public awareness of the extent of pollution and the overall environmental destruction that had taken place since the Second World War. Carson's indictment of pesticide use confirmed growing doubts concerning the technological ability of humans to manage the "resources" of the planet successfully. She also challenged anthropocentrism: "The 'control of nature' is a phrase conceived in arrogance, born of the Neanderthal age of biology and philosophy, when it was supposed that nature exists for the convenience of man."'2 Given the state of environmental deterioration by the early 1960s, the administration of John F. Kennedy was about to launch the third major conservation effort of the century (the first two occurred during the administrations of the two Roosevelts). Secretary of the Interior Stewart Udall signaled that effort with the publication of The Quiet Crisis in 1963. Like Silent Spring, it too was a best seller and outlined the "conservation" crisis. Although there was no extended discussion of Aldo Leopold, in a footnote Udall observed that Sand County Almanac was the one book that pointed to "a noble elegy for the American earth and a plea for a new land ethic. " Udall's book, however, reflected the dominant American anthropocentric "resource" approach to the environmental crisis. The revolutionary ecocentric ideas of Henry David Thoreau, John Muir, and Leopold either