Skeptical Environmentalism: The Limits of Philosophy and Science

Introduction

Skepticism is a dangerous business, not least because it is so easily misunderstood. In the ¤nal section of his Enquiry Concerning Human Understanding, David Hume noted that the skeptic, along with the “speculative atheist,” has traditionally been identi¤ed as an enemy of religion and so “naturally provokes the indignation of divines and graver philosophers.” More broadly, skepticism is often taken to be a ®at denial that any knowledge is possible, which raises the specter of the most abject rootless relativism. Hume went on to say, however, that the kind of skeptic that haunts the dreams of divines and philosophers does not exist. “No man ever met with any such absurd creature ,” he writes, “or conversed with a man, who had no opinion or principle concerning any subject or speculation .” For Hume, this left two questions: “What is meant Introduction by a sceptic? And how far is it possible to push these philosophical principles of doubt and uncertainty?”1 The ¤rst thing to know about this book, then, is that I follow Hume in his rejection of extreme forms of skepticism in favor of a moderate or “mitigated” skepticism. I even go so far as to adopt Hume’s two principles of moderate skepticism, with some quali¤cations. The human mind tends toward dogmatism, Hume noted, but when we are shown the “in¤rmities” of human understanding, we are naturally inspired to “more modesty and reserve.” This led him to his ¤rst principle: “in general, there is a degree of doubt, and caution, and modesty, which, in all kinds of scrutiny, ought for ever to accompany a just reasoner .” Further, the human imagination tends to soar to the very boundaries of the universe, against which tendency Hume offered his second principle: a correct judgment “avoids all distant and high enquiries, conforming itself to common life, and to such subjects as fall under daily practice and experience.” Thus, he advised, we should limit “our enquiries to such objects as are best adapted to the narrow capacity of human understanding .”2 While I agree with these principles in broad outline, I do not agree with the standards by which Hume himself assessed claims to knowledge. As an empiricist, Hume believed that all knowledge begins with experience, which he understood as “impressions” left on the mind by the senses, much as marks are left on a chalkboard by the impact of chalk. The mind itself is passive and contributes nothing new to knowledge. On this basis he argued, for example, that humans can have no necessary knowledge of cause and effect. No matter how many times he saw one event following another, Hume insisted, he never saw the causal connection between them. Because his model 2 Skeptical Environmentalism of consciousness excludes any other source of knowledge, Hume was left with nothing more than the constant conjunction of the events accompanied by a habitual expectation that some combinations of events somehow belong together. This conclusion makes sense only within a particularly narrow conception of human consciousness, and a more thoroughgoing skepticism would call even this conception into doubt. In addition to this quali¤cation, I would introduce a third principle to govern how these ¤rst two principles are applied: the principle of parity. In the public arena, skepticism can be a powerful weapon to use against intellectual and political adversaries, particularly when deeply held values are at stake. In the highly competitive interestgroup politics of our times, environmentalists are only too happy to raise doubts about the status quo or about the interests and arguments of their opponents. For their part, opponents of environmentalism enthusiastically return the favor. Often enough, they take up the banner of skepticism as they lay siege to this or that environmentalist claim. To win the hearts and minds of the public, advocates for all sides maintain that they alone have the best science, the purest motives, and the soundest policies and that their opponents wallow in irrationality, corruption, and folly. The principle of parity holds that skeptical principles should be applied more even-handedly. As Hume might put it, the human mind has a strong tendency to remain convinced of its own rightness—or even righteousness— in spite of evidence to the contrary. Especially when the stakes are high, humans are far less likely to scrutinize their own beliefs than those with which they disagree. When scrutiny is brought to bear and deeply held beliefs are found...