This is a really interesting article with a lot of insight into the way that human societies function and spread, and how the Culture works with those ideas.

The thing I find doubtful though - the novels are essentially an exploration of a type of society that may happen if technology progresses in a certain way. It's interesting and fun to read about, but we don't have any particular reason to believe that technology will work in such a way to make such a society possible, or whether it's actually practical if it is.

The nature of technology tends to direct a lot of the ways that societies work. The Culture essentially depends on the development of "perfect" AI. That we eventually figure out how to build General AIs that are smart and effective enough to accomplish useful things, yet never develop a desire to do things other than what their proscribed role is. Why do slap-drones become slap-drones? Do they have to volunteer for the duty, or do they just get manufactured with a desire to be a slap-drone that never changes? Can they actually be effective if they aren't capable of thinking about what they're doing and why? If they do change their minds, can they retire or switch to another job and be replaced? Who gives them their assignments and operating parameters? And the same question applies to all of the other drones and Minds and other machine intelligences that operate all of their factories and orbitals and GVSs and such.

The Culture also seems to be built around everybody in it cooperating with the general goals. In our actual society, there are lots and lots of people who disagree with the general goals, or work towards pursuing different goals that not everyone agrees with. We try to form parameters for how far you can go in various directions and how to deal with people who go past the bounds. We're also generally open to the idea of that - some of those ideas and goals might be better than what we have, so it's good to let them be tried at a small scale so they can be observed and adopted more widely if they work well. We don't see much about how the Culture would deal with such things, mostly just some people and sub-societies that leave or declare themselves separate for various reasons.