In reply to Artifacts:
Neil,
I do not believe I am misinterpreting your thesis; rather, I am simply not buying it. Artifacts do not evolve: they degenerate. Perhaps a real-life example will serve to illustrate my point.
There is an old group-sitting-around-a-campfire game that goes like this. One person whispers a phrase or a sentence to another person; that person—and each person in turn—whispers what he or she thinks they heard to the next person, and so on around the circle. The typical result is that the end product bears little, if any, resemblance to the original. The end product is not an evolutionary descendant of the initial phrase: it's the result of noise introduced into the process at each successive stage.
When—or if—microchips actually beget other microchips, silicon life will be demonstrated. Until such time, all you're really doing is mixing your metaphors. Art imitates life: it doesn't procreate it.