Environmentalism is a kind of religion, and that’s OK, William Cronon told an audience of 150 at the Chicago History Museum in late November. Just don’t get fundamentalist about it. To put it another way, Joni Mitchell was wrong: there is no garden, we can’t get back to it, and trying to do so will just make it harder to protect nature.

Cronon teaches history at the University of Wisconsin-Madison. He’s no stranger to the museum, formerly the Chicago Historical Society, having camped out in its library researching his 1991 blockbuster Nature’s Metropolis: Chicago and the Great West. The book traced in intricate, loving detail the ways 19th-century Chicago and the rest of the midwest grew up together and created each other. You might think crowded, smoky Chicago was separate from the surrounding prairie, forests, and lakes, but it wasn’t.

As with Chicago, so with you and me. Cronon told his audience that we can see ourselves as part of nature, because we’re products of geology and evolution, or we can see ourselves as outside of nature, because we stand back and judge things in a way rocks and tigers can’t. Both perspectives have value, he said, and we shouldn’t try to reconcile them or carry either one to extremes. He urges environmentalists who are trying to decide where and how to protect nature to ask both the inside-of-nature question (“Can we keep on doing this here indefinitely?”) and the outside-of-nature question (“What would this place be like if we weren’t here?”).

Cronon’s a baby boomer who spent much of his childhood in the back of the family station wagon visiting national parks. I’d bet money his family had a coffee-table book with gorgeous photographs and Theodore Roosevelt’s famous words on the Grand Canyon: “Leave it as it is. You cannot improve upon it. The ages have been at work on it, and man can only mar it.”

Since then Cronon’s realized that the idea of wilderness in this country as a perfect, unspoiled place is both wrong and dangerous. First of all, it’s been nothing of the sort for a long time. The American illusion of a virgin, unoccupied continent was created by European diseases that killed most Native Americans–who’d been remarkable managers of the land. Second, thinking of people as spoilers isn’t very constructive. To protect nature we have to change human culture to value nonhuman nature more highly and to think longer term, and if environmentalists start by defining human culture as vile, who will listen to a call for change?

It’s easy to slip from advocating preservation and conservation, as Cronon does, to making Roosevelt-like statements about all of nature. But that’s a dead end. “We go into the wilderness with freeze-dried food and Vibram soles and petroleum-based clothing,” he told his audience, even as we demand that the wild landscape be kept sacred and untouched. Yet the manufacture of that gear profaned some landscape somewhere.

It’s not that environmentalists are hypocrites. It’s that their thinking about what constitutes a landscape is often blinkered. Instead of putting wilderness on a pedestal by itself, Cronon said, “we need to imagine a just, beautiful, honorable harvest” of landscapes. He wants environmentalists to understand a broad range of them–including Naperville, the new Trump Tower, and a downstate field of soybeans–to see and appreciate all their interconnections, and to find ways to make them less destructive to the planet. Nature isn’t just faraway untouched places, and privileging those landscapes above all others won’t protect them in the long run.

Cronon’s thoughts aren’t new–Rene Dubos wrote with feeling about human-made landscapes in the 60s and 70s, and environmentalist-farmer-poet Wendell Berry attacked the idea of environmentalism serving to protect “scenic resources” in his 1977 book The Unsettling of America. Cronon shows how these ideas can be used by environmentalists to further their agenda, perhaps even restore the proenvironment consensus of the 60s and 70s.

His own work began with examining not cities and nature in general but the particulars of Chicago and the midwest, down to such crucial details as exactly how grain was bagged and sold in Chicago in the 1850s. He suggests that environmentalists follow the same path, being humble and starting small–working where they live, in particular places. Cronon serves on the boards of the Trust for Public Land and the Wilderness Society and says his new book, Saving Nature in Time, has been delayed while he helps create an interactive Web site about the university’s Lakeshore Nature Preserve in Madison (lakeshorepreserve.wisc.edu).

In the same vein, he recommends that environmentalists go easy on the apocalyptic rhetoric and be more open to the ideas of supposed adversaries. “Ranchers and loggers know things about nature that backpackers and kayakers do not, and vice versa,” he told his museum audience, and talking concretely about a particular place can help both sides appreciate this. For instance, he said, when the Wilderness Society gets together supporters and opponents to talk about the fate of places like northern Maine, it postpones the discusion of larger issues. Each person is asked to bring an object from the place under discussion and tell a story about what it means to him or her. Seated around the table, three on three, loggers and wilderness advocates often find that they bring the same objects and tell similar stories. “They may still have arguments,” he said, “but they both realize that they love the place.”