I said I was going to expand on these points, and so here I am. It seems obvious to me, and apparently to very nearly no one else, that to meet the demands of the coming centuries we need to undertake a project of scrapping the whole of our infrastructure and reworking from scratch. I don't think this is as big a deal as most people make it out to be -- better for one generation to suffer a burden of meaningful hardship, well-distributed, and leave the world more comfortable for it, than for generations onward to continue to suffer meaningless hardship, distributed to whoever's parents were too poor to get them into what will be increasingly necessary restricted spheres of education, and even more importantly, the comfort and security in early life to acclimate oneself naturally to technology.
And with that, I think we need to keep an eye towards the priorities of the future, rather than of the present or of the past. The principles which immediately spring to mind as vital in this pursuit are sustainability, education, minimizing scarcity and promoting happiness.
That last one, I think, is particularly important, because while I think most people would tend to agree that a happy species is the end goal of society, it's an easy one to lose sight of, and I think it should be laid out explicitly.
To the points of sustainability and promoting happiness, I think that any development towards a sustainable future for humanity that's worth sustaining would have to focus, a lot more than our current society focuses, on cities.
We would need to get almost the whole of the population into cities. Population density is important, because if we continue to spread out we're going to fill up the space left far too quickly and spread ourselves entirely too thin. Apart form that, maximizing the possible utility of public transportation, minimizing the need for massive shipping of goods, and maximizing the incentive and cost-effectiveness of maintaining a fair and even infrastructure, are all hugely desirable in terms of neutralizing our environmental impact.
To that end, cities should be designed to be highly desirable places in which to live. It's difficult to say how exactly to accomplish this -- I think, building from scratch would be the easiest route, but the trouble is all the best places to put cities already have cities in them. Deconstructing an existing city to rebuild would be a massive and difficult project, fraught with sociological drama. If you were to take apart and reassemble New York, which buildings do you leave? The Empire State Building is an obvious starting point for the kind of things that should survive, but the more historically significant a space is, the less likely it's going to be valuable as a present-day space in a post-industrial city. The newer a building, meanwhile, the easier it would be to remove without sociological drama, but the more likely it'd be relatively better to retrofit. (Though given the economic climate to date, I suspect we'd be better off tearing down anything built in the last thirty years just to be on the safe side.)
I want to keep talking about this, but that's all I'm going to write for now. If you have thoughts, please voice them in the comments. (They may not show up right away -- I've had a lot of spam lately, and had to turn the filters back on.)