I think evolution is more widely applicable than just to biological systems. To date, we've only studied its operation in biosystems, which, given our status as

I think evolution is more widely applicable than just to biological systems. To date, we've only studied its operation in biosystems, which, given our status as biological organisms, seems entirely reasonable. But I believe many of the exclusionary limits we put on nonbiological systems (especially computers) increasingly need to be qualified with the word "yet" - as in, "Computers don't reproduce themselves..." (yet). Evolution is a useful, powerful tool even in nonbiological systems. As a limited example, I'd offer the success of 'genetic' algorithms applied to tasks like antenna design (exemplary paper and pdf: http://alglobus.net/NASAwork/papers/Space2006Antenna.pdf http://alglobus.net/NASAwork/papers/Space2006Antenna.pdf). Where I work, we use these methods to find solutions for multiparametric optimization problems involving mechanical dynamic systems. The algorithms first generate a few thousand candidate solver variants, then pick the top ten or so best performers. These are cross-bred, and then seed the next generation of a few thousand candidates. Rinse and repeat, and within surprisingly few generations, we have an algorithm that does what we need. Although humans wrote these algos, they run in a nonbiological context - but since there's variation, selection, and inheritance, they evolve. When I see this behavior running in silico to great effect, it makes me question our limitation of evolution to biological systems. Granted, it's a primitive example, but if I'd dropped by Australia 3.5B years ago, I might have regarded the stromatolite builders as similarly primitive. On a grander scale, see Lee Smolin's concepts of cosmological natural selection (http://en.wikipedia.org/wiki/Lee_Smolin#Cosmological_natural_selection http://en.wikipedia.org/wiki/Lee_Smolin#Cosmological_natural...). And finally - around 13.5B years ago, there was only hydrogen, helium, and a bit of lithium. Today, we're having this conversation. Although we don't (yet) know the full story of how that worked, to me that's an existence proof that nonbiological matter can evolve intelligence. If computational systems incorporate evolution, I don't see a barrier to AI arising along pathways similar to those that led to us. We'll see.