Herbert Spencer had two major evolutionary theories which included the size of societies .
and the evolution from militant to industrial societies. His theory on the size of a society relates directly to the needs of society as it expanded and subsequently needed more organizations to support it. It was his belief that organizations themselves would grow and require expansions in order to adapt to the larger environments.
As for the evolution of societies he characterized militant societies or early societies as those that were more concerned with defense and offensive warfare. He even stated how warfare would initially yield a good by bringing societies together, but noted how war could have a negative effect on a society which was already developed. Industrial societies unlike militant societies are merit based in that a person is judged on his accomplishments and skills he has to offer to the society. Unlike earlier forms of society like the monarchy people aren't born into status and power, instead they have to earn it. These industrial societies also shifted the government's emphasis from telling people how to live and what they should do to only telling people what they should not do.
This idea of government having a hands off approach is something that Spencer agreed with. It is a topic that people had to deal with in the past, are dealing with in the present and will continue to debate in the future. Spencer had the "survival of the fittest" ideology and if people couldn't do for themselves, then it's best they die off and not infect the world with their unfit offspring. But unlike Darwin his statement was not just a biological idea, it had deeper political connotations to it. Here in America every election a presidential candidate expresses to the nation how much and what type of governmental programs he or she will introduce. Liberals have traditionally wanted more social programs while conservatives lined themselves closer to Spencer's ideas.