"We prefer rational systems. Contrast this with evolution, who is the worst spaghetti programmer in the known universe. The problem is rational programs are more hackable. After all, if the code is optimized to be understood by humans, it's therefore optimized to be hacked by humans.
"Of course, the problem with instituting Darwinian algorithms is that we may well have problems understanding how the damn things work (for instance, the Darwinian algorithm may use an intermittent short in the machine it's running on as the basis for its random number generator). This can lead to cargo cult-style programming (I don't know why this works, I just do it 'cuz the machine tells me it works), and that is arguably a worse problem than rational programming."
-- heteromeles, 2010-08-21