Are there ecological limits to population?

Policy on population and environment in the United States and abroad has been vacillating, unsure of its course; it would be more decisive if the several disciplines could agree on the nature of the problems and their urgency. The two disciplines principally concerned are biology and economics, and the contribution of this paper is to identify eight of the many axes or directions on which the methods and traditions of the two are different. For example, the first of the axes runs between contingency and orderly progress, with biology tending to seek out the former and economics the latter; thus biologists can more easily comprehend catastrophes, such as the demise of the dinosaurs or widespread desertification. The third axis concerns indefinite market-driven substitutability, seen by economists as resulting from scientific discovery; natural scientists, including biologists, whose discoveries make possible the substitutions, are skeptical. Axis 7 results from the fact that economics concentrates on goods that are on the market, and so deals with a truncated part of the commodity cycle, while ecology aims at the whole; because goods disappear from economic statistics once they pass into the hands of consumers many of their ecological effects are invisible. I believe that from similar further study of the two disciplines a common set of policy recommendations will ultimately emerge.