Diaspora

By Greg Egan,
By the end of the 30th century humanity has the capability to travel the universe, to journey beyond earth and beyond the confines of the vulnerable human frame.

The descendants of centuries of scientific, cultural and physical development divide into three: fleshers — true Homo sapiens; Gleisner robots — embodying human minds within machines that interact with the physical world; and polises — supercomputers teeming with intelligent software, containing the direct copies of billions of human personalities now existing only in the virtual reality of the polis.