The answer is, we shouldn't engineer a society. But we should respect us as beings with the ability to bring our own purposes in harmony with our fellow ones and with the greater society. This is almost often a hard task, but only we could do it. I would understand Adam Smith so, that it is possible to bring out of realizing self-interests the best for the society. It is possible, but not a natural law. Our whole self, our intelligence, our emotions our morals and everything what makes us human is required that this becomes possible. Therefor no recipe exists to bake an perfect society. If we delegate responsibilities to an higher instance we loose some of the power to make the world a better place.
My perspective comes from Degrowth. It is a relative young movement, which tries to form an economy where is more harmony in our relationship with living nature and it wishes to create possibilities for a good live for everyone on our planet earth. We learned that we only can reach this goal if we talk about and work for this target. We can only show points where the current economy fails, to reach this goal. But we don't have an plan and maybe will never have one, who says us, this is the way we must go. Everyone is responsible to define for his- or herself what good live means. We make small steps, and ask after nearly every step, is it right or wrong. We think our world has room for many societies, maybe some are planned other ones are complete chaotic but the art of this kind of economy is, that they all can prosperous coexist.
The concept of self-interests is often misunderstood as being the same as private interests. If a fence is required to protect my private sphere from the rest of the world this is already an lost in the self-interest to not enclose the view to the wider world.
We all live in a very exciting time. The value of land is still the most well-founded orientation to assess things. But the scientific knowledge and the economic use of land have made it possible that more people from less land could live sustainably. We currently overuse our resources excessively, but we believe that the human species can only survive on a viable globe. That's why ecological argriculture is so important. Degrowth collaborates with Nyéléni movement for food sovereignty and Via Campesina.
Another key element is communication. The plenty of energy provided by fossil fuels is used to build a network that help us to work together globally. Not the interests of a particular group satisfy our own interests, but the joined interests of all of us.
We should not overestimate the power of choice. Today we can choose between electric power from fossils and from renewable energy sources. But we are confronted with the hard truth, that the right choice is to use less power at all. We must stop in believing that energy is not scarce because it is relative cheap. It is cheap because it is a good which does not differ in quality, but it makes a big difference where it comes from if the home of people is destroyed to produce it. Similar sad stories can be told about our food, our clothes and nearly everything what we consume. Why do we need to call some products fair traded? We need free trade and free trade should be identique with fair trade, every time and everywhere.