A central theme in the speculative writing on technology of the past century is that forms of technics, like forms of biological life, undergo a process of evolution. With the passage of time, newer and more sophisticated varieties of apparatus, organization, and technique rise to replace older, simpler varieties. New technologies enter into areas of social existence where they had not been previously. Just as Darwin observes that the various species of life on the Galapagos Islands tend to specialize and diversify into particular biological niches, so it is that forms of technology continually spread into fresh areas of social utility. In both number and diversity the kinds of technical artifice available to human societies increase.