Far too often, politics and policy are portrayed as a battle between liberals and conservatives, or socialists vs. capitalists. But one of the most profound divides of modern times is between optimists and pessimists-- especially over how they view the environment.

This episode looks at the debate between environmental optimists (wizards), who believe we can invent our way to a better, healthier future, and pessimists (prophets), who say we must impose limits on pollution, over-crowding other impacts of humans on the planet.

Our guest, journalist, Charles C. Mann, author of new book, "The Wizard and The Prophet", is a correspondent for The Atlantic, Science and Wired. Two of his previous books, 1491 and 1493, were widely-acclaimed best sellers.

We consider the dueling visions of two remarkable scientists. Norman Borlaug's research led to the Green Revolution, which saved hundreds of millions of lives, and boosted agricultural production. He was awarded the Nobel Peace Prize for his work. William Vogt, who saw the world as bound by immutable biological limits, was the founder of modern environmentalism, perhaps the most successful ideology of the past century. His book, "Road to Survival", which inspired generations of environmental activists.

Do apocalyptic environmentalists sometimes seem heartless about the lives of poor people? Are technological optimists are too optimistic about the future, with ideas that lead to global domination by massive, centralized corporations and economic systems? We unpack these and other challenging questions.