In short, we know that up to some unknown set of limits, knowledge, institutions, and manufactured capital can substitute for natural resources, so that even if an economy loses some of its natural capital, in quantity or quality, its wealth would increase if it invested sufficiently in other assets. The remarkable increase in agricultural productivity over the past two centuries demonstrates this clearly.
简而言之，我们知道在某些未知的限度内，以及一定的知识和制度条件下，制造型的资本可以替代自然资源。所以即便一个经济体在质与量上损失了一些自然资本，如果对其它的资产有足够的投入，其财富还是会增加。农业生产力在过去两个世纪的显著增长清楚地证明了这一点。