'Irreversibility' and Social Justice
THE distinguishing feature of this second conception of environmental sustainability (Conception B) is its focus on the sustaining of irreversible nature. As I pointed out in Chapter 2, irreversible nature may also be critical natural capital, but not necessarily so. Critical natural capital is capital critical for the maintenance of human life, while irreversible nature is irreversible in the sense that once it has gone it cannot be recovered. Some irreversible nature--a determinate species, for example--may be critical for human life, in which case it will straddle Conceptions A and B, and the reasons for sustaining it will be drawn from either column (this conclusion is represented in Box 5 of Table 2 by including human welfare as a reason for sustaining irreversible nature). But other species may confidently be said not to be critical for the maintenance of human life, and so their disappearance will not be a cause for concern within the confines of Conception A. In Conception B, though, 'duties to nature' make their first appearance as a reason for sustaining (irreversible) nature--that is, we may want to sustain it irrespective of whether it is functional for human welfare or not. Up to now I have referred to 'duties to nature' rather than 'obligations to nature', or 'justice to nature', because these last two descriptions would imply that nature somehow has a claim upon us in respect of obligations and/or justice. Such an implication would require substantiation of a sort which it is not my intention to provide here, although I shall spend some time in what follows discussing to what extent the language of justice--and particularly distributive justice--is applicable to the non-human natural world.
This last remark indicates that we shall be largely concerned here with the first row of the distributive justice table developed in