In many ways the theory of justice which Rawls developed and refined is not obviously any more promising as a basis for developing a theory of ecological justice than are those of Nozick and Walzer. It, too, seems to presuppose that justice is something which fundamentally can obtain only between fully fledged moral persons. As was the case with Nozick and Walzer, Rawls barely discusses the morality of relations between humans and non-humans. Also, Rawls and Nozick share at least one point in common, namely the Kantian starting point that justice concerns the relations between autonomous beings capable of mutual recognition as moral equals. However, it has from time to time appeared possible to find materials within Rawls's approach to facilitate the construction of a theory of justice which allows a natural place for non-persons. To understand these possibilities we need to say a bit more about the development of Rawls's ideas.
As is well known, Rawls's theory went through various stages of development, among which some of the most important occurred after the publication of A Theory of Justice. The crucial move here involved the reconceptualization of Rawls's theory by its author as a political rather than a comprehensive, or metaphysical, doctrine. By this he meant that he offered it as a way of understanding how, within pluralist societies, it would be possible to find an 'overlapping consensus' between citizens with different value commitments on fundamental constitutional matters so as to enable a well-ordered society to exist, rather than as a doctrine of the ideal society which could only ever hope to attract the adherence of a limited number of people (Rawls 2001).
Corresponding to these two stages are two ways of looking for room to embody a theory of ecological justice within Rawls's theory. The first is to examine whether his device of the Original Position could allow non-humans entry into the debate on justice, by a suitable thickening of the veil of ignorance behind which the participants in the Original Position are supposed to engage in their deliberations. The second is to analyse the concept of the overlapping consensus within political liberalism in order to find room for the idea that non-humans can have a claim to be treated justly within Rawls's well-ordered society. As it turns out, the former approach has the great advantage, from the point of view of ecological justice, that if it succeeds then non-humans can be given some form of constitutional protection for their interests. However, unfortunately it does not succeed. The latter