"It's the basic obstacle of artificial ecosystems. In a normal evolutionary environment, there's enough diversity to cushion the system when something catastrophic happens. That's nature. Catastrophic things happen all the time. But nothing we can build has the depth. One thing goes wrong, and there's only a few compensatory pathways that can step in. They get overstressed. Fall out of balance. When the next one fails, there are even fewer paths, and then they're more stressed. It's a simple complex system. That's the technical name for it. Because it's simple, it's prone to cascades, and because it's complex, you can't predict what's going to fail. Or how. It's computationally impossible." Holden"