One idea behind the Culture as it is depicted in the stories is that it has gone through cyclical stages during which there has been extensive human-machine interfacing, and other stages (sometimes coinciding with the human-machine eras) when extensive genetic alteration has been the norm. The era of the stories written so far - dating from about 1300 AD to 2100 AD - is one in which the people of the Culture have returned, probably temporarily, to something more 'classical' in terms of their relations with the machines and the potential of their own genes.
- A Few Notes On The Culture