I have only a few words, so I am going to jump quickly into the fray and defer some pretty important elaborations to future posts.
Assertion: Sustainability is about maintaining possible futures that are at least satisfactory to the humans currently living on Earth. (After all, we are the ones currently calling the shots.)
Taking that as a starting point, the obvious question is, “how do we decide which futures belong in our global portfolio?” My individual portfolio is probably pretty similar to yours, but it is likely to be very different from that of a farmer in a developing country. Even in very different portfolios, there are likely to be some elements of commonality, but how do we resolve the inevitable tradeoffs and incommensurability?
Given my rearing by reasonably liberal, middle class parents here in the US, complete with public school civics and government classes, I argue that democratic processes should be central to answering this question. And those processes are going to have to be much more sophisticated than “winner-takes all / choose between 2” voting. Further complicating things is Kenneth Arrow’s Noble-winning proof which showed that there is no way to uniquely choose between 3 options under conditions that we take for granted as fair. And even if we ignore Arrow, we are not going to all get together and rank our own portfolios, much less the union of all portfolios of possible futures... This is a very hard problem of values and institutions.
Difficulties aside, I see this challenge as absolutely central to sustainability and much more complex than “paper or plastic?” Current choices matter, but their meaning is greatly enhanced if they are made in the context of collectively imagined futures.