Bugs don't evolve but the bug generators do. We build code with more and more complexity until we reach an equilibrium with our ability to debug the systems. I

Bugs don't evolve but the bug generators do. We build code with more and more complexity until we reach an equilibrium with our ability to debug the systems. If there is no competition in the evolution then systems can become arbitrarily baroque and fragile, which leads to rules like 'no software updates/patches' and 'all config changes via the CCB and pass mandatory tests' or 'your problem is handled manually', the wire wrap of systems development. Rebooting (the process or the computer) is trimming the state space. Model checking driven design really helps tame the tendency to let program state evolve without bound. FP tends to follow a bottom up design which makes this easier too.