What is a major theme?

In the universe imagined through the words of Arthur C. Clarke, the power of science and technology is virtually limitless. The only barriers standing in the way of what technology can accomplish reside in the mind of the individuals who are using it. The alien world of the Ramans is a purely technological response to the problem of survival through time and space, and to an extent, to the problem of life itself. Rama is a self-contained, artificially created universe that is, from a technological perspective, perfect. Rama is designed to "live" forever as it recycles itself indefinitely. No one and nothing ever dies on Rama. Everyone and everything is simply recycled and reused. Rama is a purely functional world where everyone and everything has a purpose from which it does not deviate. The "biots" that the world of Rama generates are neither alive nor dead. Rama is a machine that lives for the sole purpose of keeping itself alive indefinitely. In a way, it mirrors the human world while turning it outside in.