Andrew Dobson has outlined three conceptions of environmental sustainability: the ‘critical natural capital’ conception; the ‘irreversibility’ conception; and the ‘natural value’ conception. He has also attempted to map out the various ‘dimensions of social justice’– his purpose in so doing being to analyze the ‘encounter’ of each conception of environmental sustainability with the points on his map. Not surprisingly, Dobson concludes that as one moves from the ‘critical natural capital’ conception through the ‘irreversibility’ conception to the ‘natural value’ conception of ‘sustainability’, the ‘points of contact’ with his map of ‘the dimensions of social justice’ are found to ‘become fewer and further apart’. In this article I argue that Dobson is fundamentally confused in his reason for thinking why this is so. I also argue that a core argument he deploys concerning future generations cannot do the work he requires of it.