One of the arguments that environmentalists use against factory farming and burning fossil fuels is that these activities are "unnatural" or that they "go against nature." But what exactly is this "nature," and who gets to define it? The answer is that nature actually comes from culture.
In the west, many of our common sense ideas about nature can be traced back to a debate that brewed between political philosophers in the seventeenth and eighteenth centuries. Their debate, which is by no means settled even to this day, centered on human nature. Are we inherently evil and greedy, or inherently good and altruistic? To answer, philosophers 300 years ago turned to what were then called "savage" peoples, mostly Native Americans, trying to figure out how humans acted in a "state of nature."
Probably the most famous comment in this debate came from the quill of Thomas Hobbes, who commented sardonically in his masterwork The Leviathan that life in a state of nature was "poor, nasty, brutish, and short." Others argued that savages were "noble" or "gentlemen" precisely because they lived in harmony with the world around them and weren't burdened by the strictures of morality and economics.
In these debates, "nature" was understood as everything that stood outside civilization — not just trees and wildlife, but also any humans who didn't live exactly like Europeans. So even at its inception, this idea of nature depended on two dubious propositions. First, European philosophers mistakenly imagined that tribal peoples lived outside the influence of culture, religion, and other institutions that would curb their innate tendencies. Second, the philosophers suggested that humanity stood outside nature, as if there were some stark line between modern humans and every other biological thing on the planet. Given that nature was so nasty, at least according to Hobbes, it's no wonder they wanted to make this assumption.
Even the eighteenth century philosophers who believed in humanity's natural goodness, like the Earl of Shaftesbury, bought into the idea that nature was separate from humans. Our great feats of empire building, morality, and science separated us from dogs, insects, and gentleman savages. In the United States, transcendentalists like Henry David Thoreau took up this idea again in the mid-nineteenth century, and tried to embrace goodness by moving to bucolic areas far from cities. You cannot yearn to get back to nature if you don't believe that you are fundamentally not a part of it.
You can see this same old debate alive in environmental politics today. Like Hobbes and his cohorts, we've reached a point in our civilization when we can no longer deny that human have the power to change the Earth's environment forever. There are two possible responses to this issue. One is to argue, with many environmentalists, that sustainable development depends on going "back to nature," cutting back energy use, and leading slower, de-urbanized lives. This is a kind of gentleman savage argument, where nature is good. At the other end of the eco-aware spectrum we find a very different argument, coming from geologists like Peter Ward, which is that we need to develop geoengineering technologies that will take complete control of nature to scrub carbon out of the air, clean polluted waters, enhance the productivity of farms, and more. Civilization and science can rescue nature, just as Hobbes' social contract could rescue human nature from greed and brutishness.
Of course there are many positions between these extremes, too. But the theme that unites them is a strong echo of the centuries-old belief that humans have somehow stepped outside nature. The problem is that humans are, in fact, part of nature. We are animals who live in burrows and hives like bears and bees. We leave our poop and garbage everywhere just like raccoons do. Sure we've invented some elaborate philosophies and ideologies to explain hives and poop to ourselves, but that doesn't mean we're not part of nature. All those tools we have to pollute the planet? Natural. Other animals use tools. And our changed climate, altered by pumping carbon into the atmosphere? Sorry to break it to you, but that's part of the natural carbon cycle, in which the environment slowly cycles between hot and carbon-rich followed by cold and oxygen-rich. Humans and our environment-altering garbage are about as natural as it gets.
It's time we got away from eighteenth century thinking and started to admit that humans are actually a part of nature. And because we are natural, we can only thrive when our ecosystems have a very specific climate and are full of specific life forms. Preserving the environment in a human-friendly state like the one where we evolved won't bring us back to nature — it will simply make the Earth really comfortable for us and our fellow life forms. Whether we preserve the environment with enormous, futuristic climate-control machines or by leaving the cities for tribal life, we are doing natural things on a natural world that is in a natural state. There is no nature to return to. We are already here.