Computation is mathematical calculation. The brain does not do straight math like computers do.
Most of what we think we know of "consciousness" is based on estimation and assumption, but from the very best research out there we know that the brain is a molecular machine. Through a system made of billions of neurons interacting through neurotransmitters and electrical/molecular forces, we end up with processes like Long Term Potentiation (http://en.wikipedia.org/wiki/Long-term_potentiation) for memory.
Negative feedback loops (for hormones), neurotransmitter synthesis, LTP, and "thought" do not come from mathematical calculation performing a set of predetermined functions (like software)-- they come from molecules governed by the forces of physics leading to a system designed by the processes of evolution.
computers can be programmed to do estimation and statistics and that sort of thing. they can also have sensors and feedback mechanisms, and calculate anything the forces of physics would do. evolution can also take place within a computer.
I think you're missing the point, mainly that all that is programmed. There is no way a computer can truely evolve, only its software can.
Evolution is the response to external factors, mainly death, which prevents the spread of genetic material.
Now if you were to make an android that had all the risks a human does, like being hit by a car or eaten by a lion, and gave it two ROM sequences of commands that its consciousness is based on and whenever two androids 'reproduce' they only pass on one ROM sequence, then you would end up with genetic selection. Essentially all new androids would end up with the ROM sequences of the most successful andriods.
Factor in that there might be write errors and data corruption from radiation turning a 0 into a 1, then they might get true evolution.
However, a desktop computer or mainframe cannot evolve as it's one entity. Even thousands of them won't evolve as new computers aren't made through the joining of two hardware parts of two older PCs. It isn't like "aww he's got your webcamera, honey" or "Oh no, he's got a cooling fan defect, one of the heat sinks isn't working properly".
If PCs suddenly started becoming self-aware, every single one would be an alien to each other as it would be fundamentally unique.
A large portion of Asian people descend back to Ghengis Khan, Irish descend back to some warlord there. Our genetic tree as a species is illustrated by irregular growth and random dead ends, a computer won't achive that ever until they become so unrecognisably living that they risk being killed or eaten or choose not to have offspring, or conquer a country and have 500 kids with random androids.
Then there's things like Founder effect to consider, like a Micronesian islands population has 5% colour blindness and 30% carry it even though it's a 0.003% prevelance in the US. Why? Because everyone but 20 people died after a typhoon and 1 of the survivors had it, and since 1775 1/20th of the population is totally colour blind. If he'd have been killed, they'd have had 0% prevelance of colour blindness.
Most of what we think we know of "consciousness" is based on estimation and assumption, but from the very best research out there we know that the brain is a molecular machine. Through a system made of billions of neurons interacting through neurotransmitters and electrical/molecular forces, we end up with processes like Long Term Potentiation (http://en.wikipedia.org/wiki/Long-term_potentiation) for memory.
Negative feedback loops (for hormones), neurotransmitter synthesis, LTP, and "thought" do not come from mathematical calculation performing a set of predetermined functions (like software)-- they come from molecules governed by the forces of physics leading to a system designed by the processes of evolution.