Survival of the species depends on adaptability, Frank Herbert argues, and that depends on variability, variation:
I think that big government is one of the major dangers in our world. It tends to homogenize a society, and our strength is in our variations. The bigger it is, the worse it is. Small governments, small societies — developing their own mores, their own social systems, their own people, going their own ways to a limit — do not endanger their neighbors. I hope to God we get off the planet soon, because that’s what will happen in space. The difficulty of communication across space at our present level of technology dictates that if we get off this planet with a viable breeding population of humans, and if they scatter into different directions, each group is going to develop in its own way. Variation means the species will survive. And that’s what I’m addressing in the Dune books.