Life on Earth is the product of evolution in the medium of carbon chemistry. However, in theory, the process of evolution is neither limited to occurring on the Earth, nor in carbon chemistry. Just as it may occur on other planets, it may also operate in other media, such as the medium of digital computation. Just as human artists are able to express their creativity in a variety of media, so can evolution.
In recent decades, there have been a wide variety of implementations of evolution in the digital medium. While these have varied greatly in the degree to which the selection is natural or artificial, it is essentially the same creative evolutionary process that has expressed itself so richly in the organic medium on Earth.
Contemplating the richness of organic evolution raises the question of how richly the same process can express itself in the digital medium. In the experiments conducted to date, we have seen dramatic transformations in the replicators, however, we have not seen the emergence of hierarchically organized complex structures comparable to the products of organic evolution.