Humans have shifted how we think on a basic level many times, this is one thing to understand when writing anything set in the far future. If you want to show someone in the year 3,000 AD you need to try and think of how he will be different, not just in body but in how he will think.
To explain what I mean I will detail out a few paradigm shifts we have gone through.
The first is the age of enlightenment in Europe. The short explanation of this is that it’s when we changed from assuming things that we did not understand were supernatural to assuming they were understandable scientific phenomena. This sounds simple but it is not, it changed everything about our civilization.
The second is who people identify with. In a very real sense civilization happens when people decide they belong to more then just their family. At first this might mean their tribe, but then it grew to a city, and the city grew to into a nation.
What shifts do you think will happen in the future? Could we even accept them today if someone came from the future and told us about them?