Economic logic requires that we maximize the productivity of the limiting factor in the short run, and invest in increasing its supply in the long run. When the limiting factor changes, then behavior that used to be economic becomes uneconomic. Economic logic remains the same, but the pattern of scarcity in the world changes, with the result that behavior must change if it is to remain economic. Instead of maximizing returns to and investing in man-made capital (as was appropriate in an empty world), we must now maximize returns to and invest in natural capital (as is appropriate in a full world). This is not new economics, but new behavior consistent with old economics in a world with a new pattern of scarcity.

Herman E. Daly (1994) in: AnnMari Jansson. Investing in Natural Capital: The Ecological Economics Approach To Sustainability. 1994. p. 24