The Wizard and the Prophet: Two Remarkable Scientists and Their Dueling Visions to Shape Tomorrow's World

by Charles C. Mann

Which of the two farms is more productive? Wizards and Prophets would disagree about the answer, because they disagree about the question. To Wizards, the question means: Which farm creates more calories—more usable energy, in Weaver’s terms—per acre? Scores of research teams have tried to appraise the relative contributions of organic and conventional agriculture. These inquiries in turn have been gathered together and assessed, a procedure that is also fraught with difficulty (researchers use different definitions of “organic,” compare different kinds of farms, and include different costs in their analyses). Nonetheless, every attempt to sum up the data that I know of has shown that in side-by-side comparisons, Howard-style farms grow less food per acre overall than Liebig-style farms—sometimes a little bit less, sometimes quite a lot. The implications for the world of 2050 are obvious, Wizards say. If farmers must grow twice as much food to feed the 10 billion, following An Agricultural Testament ties their hands. Prophets smite their brows in exasperation at this logic. To their minds, evaluating farming systems wholly in terms of calories produced—in terms of usable energy—is a perfect example of the flaws of reductive thinking. It does not include the costs of overfertilization, habitat loss, watershed degradation, soil erosion and compaction, and pesticide and antibiotic overuse; it doesn’t account for the destruction of rural communities; it doesn’t consider whethe...