Good theory, like good art, simplifies, abstracts, and highlights. It is therefore, in a sense, inappropriate to ask whether Malthus believed his conditions to be complete and detailed descriptions of reality. Of course, he did not. A really good theorist is a hair-splitter only when necessary, or when engaged with a critic. The proper question is whether Malthus believed his theory and conditions to be essentially accurate. And to this, the answer is certainly that he did...
In Malthus' time, a considerable part of "final" or virtually final output was agricultural goods... Thus, if a man stood on a square mile of land, or a nation on 3,000,000, the natural resources relevant for economic activity could be easily identified and measured. They were acres of cropland and pasture, board feet of standing timber, etc.
What has happened since those times to the meaning of final goods, the methods by which they are produced, and the definition of natural resources is so profound that we find the novelty difficult and seek simplification in possibly archaic analogies... More than 90 percent of the increase in real gross national product in the United States since 1870 has been of non-agricultural origin. Finally, the natural resource building blocks have changed radically—they are atoms and molecules... In significant degree, even the ultimate limits are different from Malthus'. His natural resources were conceived for a two-dimensional world nourished by acreage. Ours is a three-dimensional one, sustained by subsurface resources. His society could reach natural resources to only insignificant distances above and below his acres. We have multiplied our "reach" by many thousands.
—Harold J. Barnett, of RFF, at the Universities-National Bureau Conference in December, 1958.
A version of this article appeared in print in the May 1959 issue of Resources magazine.
