Well, one measure of a good life, I think, is to be engaged in projects that one thinks are meaningful and worthwhile. So I would put the emphasis of a good life on activity, on the walk rather than the destination, and I think that most of the things that any of us do that are really valuable and really important are projects that we really shouldn't expect to be completed in our lifetime because if they could completed in our lifetime, they probably wouldn't be so important that we should devote our lives to them.

I think when it comes to climate change, the single most important thing in the world is for the United States' Congress to pass an effective bill that will put a price in carbon because if it starts costing something to emit carbon, this will provide an incentive, people do act on the basis to some extent of economic incentives to emit fewer greenhouse gases.

I think the challenge of climate change in particular is the challenge for us to create and produce new norms for a new kind of world. And that's why I think as important as the issue of climate change is, it's even more important than it seems because if we can't evolve very quickly, new norms to deal with issues like climate change, we're not going to be able to survive in the kind of world we've created. So I think, really, the whole nature of democracy, of governance, of global community and of solving the kinds of problems of the 21st Century are really at stake.

Bentham spent much of his life writing constitutions and proposing legal reform in the light of his utilitarianism. The evaluation of particular acts was hardly his concern. The psychology of his day was hedonistic and he worked in that framework and passed it on to Mill, but it is clear as day that Mill was not a hedonist in the sense in which we use that term today, though he used the language of pleasure and pain to express his views.

Climate scientists think of nothing but climate and then express their concerns in terms of constructs such as global mean surface temperature. But we live in a world in which all sorts of change is happening all the time, and the only way to understand what climate change will bring is to tell stories about how it manifests in people's lives.

People with long memories and a vivid sense of the past have an immediate understanding of politicians like Donald Trump. They are not surprised by the behavior of Google, a corporation that notionally (until recently anyway) espoused the slogan "don't be evil" and then runs over individual people and even entire nations in the pursuit of profit.

Our differences should not be exaggerated.