The trouble with justified optimism is that it’s sometimes accompanied by the foolish kind. Many acknowledge the accomplishments of the Paris climate summit in December—getting close to 200 hundred nations to agree on a basic if nonbinding framework for combatting climate change is no small feat—but also note the significant challenges that remain. Yet with all the necessary reminders and caveats come excited pronouncements on the unnamed innovations that will save the planet from ourselves, and expressions of faith in their inevitability.

You can hear it in the statement of Secretary of State John Kerry after the close of the summit: “It won’t be governments that actually make the decision” about how to tackle climate change, he said—“It will be the genius of the American spirit. It will be business unleashed.” You can hear it in the words of Miami Beach Mayor Philip Levine, whose city increasingly finds itself endangered by rising sea levels:

“I believe in human innovation,” he said. “If, thirty or forty years ago, I’d told you that you were going to be able to communicate with your friends around the world by looking at your watch or with an iPad or an iPhone, you would think I was out of my mind.” Thirty or forty years from now, he said, “We’re going to have innovative solutions to fight back against sea-level rise that we cannot even imagine today.”

Of course, belief in American ingenuity is as old as belief in American exceptionalism, if not the same thing. But when it comes to climate change, waiting for innovation to come to the rescue amounts to a kind of complacency, the exceptionally American kind that arises from abiding belief in the beneficence of the market.

Commenters like Jedidiah Purdy, writing in Foreign Affairs, term expression of this attitude the “Good Capitalocene.” “Here," Purdy writes, “no one really believes in political change, but they hope some mix of investment policies and exhortations will spur private capital to remake the world, specifically through crash investments in renewable energy sources.”

The “Good Capitalocene” in this way seems like an outgrowth of the Superfreakeconomics school, the adherents of which pose clever, counterintuitive, and easy “solutions” to thorny issues like climate change. Elizabeth Kolbert of The New Yorker wrote memorably about such cockamamie proposals to cool the earth as pumping sulfur dioxide into the stratosphere through an eighteen-mile-long hose, and panned the gross oversimplification of Superfreakonomics’ authors, who stated: “When the solution to a given problem doesn’t lie right before our eyes, it is easy to assume that no solution exists. But history has shown again and again that such assumptions are wrong.”

There’s obviously nothing wrong in hoping for innovation. The trick is not to substitute it for action (or use it to justify inaction). Anna Clark at Greenbiz says any idea that “the Paris accord [will] unlock capital to drive transformative innovation in private industry” is really just theory. “In reality,” she writes, “a blend of best practices and better policy likely will inform industry’s response” to addressing climate change. The Economist made a similar appeal to reason in its December 19, 2015, issue:

[I]increased R&D on its own is a necessary condition for progress, but not a sufficient one. Backers need to ensure that it leads to innovative solutions which can be installed on a commercial scale, rather than becoming a self-perpetuating academic exercise…. [C]ountries will have to make full use of the mechanisms for ratcheting up emissions cuts and accelerating adaptation for decades to come. … Sustained determination is crucial.

Faith in innovation is not enough, in other words. As someone else reminded us in an encyclical on the environment last summer: “The same ingenuity which has brought about enormous technological progress has so far proved incapable of finding effective ways of dealing with grave environmental and social problems worldwide” (Laudato si', Chapter 5, 164).