ABSTRACT

The proponents of strong sustainability have advanced four main arguments for the non-substitutability of natural capital: the existence argument, the Aristotelian argument, the motivation argument, and the argument from critical natural capital. This paper argues that the first three arguments fail while the fourth cannot be properly assessed without clarifying the notion of critical natural capital. To that end, this paper develops a specific account of critical natural capital as ecological conditions required for the continued existence of economic agents. This improved argument establishes that strong sustainability is probably true, but it also reveals that it may not matter for the purpose of public policy.