Some radical or “dark green” environmentalists claim that the Western tradition in philosophy—and political philosophy most especially—is replete with subtle, systematic, and pervasive prejudices against the weak: women, minorities, animals, and, weakest of all, generations yet unborn. We therefore need a radically new philosophical discourse, an entirely new ethic, if we are to respect and protect the health of the earth and the well-being of future people. The proposed counterdiscourse is almost invariably characterized by its adherents with the prefix “post” and the suffix “ism”—post-humanism, post-individualism, and the like. The concepts, categories, and frameworks that belong to “Western culture” need to be obliterated and replaced root and branch by something at once new, non-Western, and not at all beholden to the “dead white men” whose works comprise the “canon” of Western political and philosophical thinking. What is allegedly required, in short, is a Nietzschean “transvaluation of all values” if we are to preserve the planet, protect fragile ecosystems, and save human beings from themselves.

Now along comes the distinguished—and decidedly Western and female—classicist and political theorist Melissa Lane, to counter that we don't need an entirely new ethic, but we would be wise to consider reviving at least parts of a very old one propounded by that deadest of dead white males, Plato. Her contention is not that Plato was an environmentalist avant la lettre, but that his works—The Republic in particular—contain the kernel of an ethic or ethos of environmentally responsible citizenship. The result is a readable and riveting inquiry into and critique of some of our most cherished but unexamined assumptions and prejudices.

Lane's book is divided into three mutually reinforcing parts. Part I takes up the topic of inertia, i.e., our inability (or unwillingness) to critically reconsider our comfortable habits and the conventional wisdom that underwrites them. In Part II she tells us how and why this is a failure—individual and collective—of political imagination. Our inertial imagination can be challenged, and perchance changed, by a close and careful reading of ancient authors, Plato in particular. Part III is concerned with the need for individual initiative in reimagining our present predicament so as to change our ways of thinking and thus of acting.

Unlike many (most?) books by environmentalists or green political theorists, Lane's is “primarily concerned with human-to-human interactions rather than with our relation to the natural world” (p. 15). And that is because we cannot begin to change our too-often destructive and unsustainable relation to the natural world until we change our relations with each other. Ancient authors, Plato preeminent among them, employed a number of concepts that we would do well to reappropriate. Each virtue (arete) has a corresponding vice, and each vice a corresponding virtue. To begin with the vices: One is pleonexia, “literally grasping-for-more, meaning an immoderate overreaching for more than one's share” (p. 32). Another is hubris. Usually translated (not entirely satisfactorily) as “pride,” hubris is an overweening arrogance, a misplaced confidence in one's talents, abilities, and knowledge.

You need not look far to find examples of modern pleonexia: rampant consumerism is a particularly prominent one; the mania for economic growth at all costs is another. To the question, “How much is enough?” too many of us answer that one can never have enough. Lane is not lambasting consumption or economic growth as such but greedy and immoderate “pleonectic consumption” and growth. The virtue corresponding to and contrasting with the vice of pleonexia is sophrosune, typically translated as “moderation” or “temperance”—Lane prefers “self-discipline”—and it is in rather short supply in our modern capitalist-consumerist society. Yet, it is sorely needed, now more than ever, since the root of the recent financial collapse and our myriad ecological crises are one and the same (pp. 120–24). Where self-discipline is absent, external regulation is required; but the psyche of the pleonectic or immoderate person will resist even that (sound familiar?).

Lane invokes repeatedly the image-story of Plato's cave. Briefly, Plato has Socrates construct an allegory about prisoners in a cave, chained fast so that they cannot turn around to see the fire that burns brightly behind them. They mistake the shadows on the wall in front of them for reality. That is what they are accustomed to seeing and believing. Then one day a prisoner manages to escape and to make his way out of the cave, where he sees real objects in the bright light of the sun. He reenters the darkness of the cave to tell his fellow prisoners that they have been deluded all their lives; they have mistaken appearance for reality. But, far from appreciating the truth, they call the escapee crazy and would, if they could, kill him. The lone enlightened prisoner is like the philosopher who earns the enmity of others by asking discomfiting questions. Lane uses this allegory to illustrate “inertia”—the comfortable conventional wisdom to which the prisoners subscribe that renders them docile and inactive—and the lone prisoner's escape and return exemplifies “initiative”—the idea that one person's action can potentially make a difference by educating and enlightening others. To make such a difference requires risking ridicule and rejection. But, nothing ventured, nothing gained, at least as concerns the transformation of our collective imagination. It once seemed unimaginable that slavery would be abolished or that women would one day enjoy the same rights as men; but small bands of abolitionists and suffragettes dared to imagine just that—and to overcome inertia by taking initiative—and our world has been transformed for the better.

We are in dire need, Lane contends, of just such a transformation in environmental matters, and this must begin in imagination—not only our individual imagination but our shared or collective imagination. Each underwrites and reinforces the other. Plato, the philosopher of the most vivid and expansive imagination, can help: first of all, by his own very bracing example, and second by helping us to think about and reimagine the relationship between polis and psyche, city and soul. Plato was hardly alone in contending that each mirrors and reinforces the other. Those who live in a sick city—one that values pleonectic overreaching and rewards outsized pride—are themselves likely to be sick and to further contribute to the sickness of their city. Among the questions Plato poses is how to heal a sick city and the sick souls who inhabit it. One problem is that pleonectic and hubristic people don't know (or understand) that their souls are sick or that greed and pride are soul-diseases. They can discover this, Lane argues, with the help of a knowledgeable and skilled diagnostician. Enter Dr. Plato. A close, careful, and sympathetic reading of his Republic will help us begin the road to recovery. What Lane does, in effect, is to help us read and begin to understand that charmingly complex work, and in a way that will lead us to live our lives as thoughtful stewards and citizens of an environmentally sustainable society.