In his theory Perrow recognized that modern systems are made up of thousands of parts, including fallible human decision makers, which interrelate in ways that are, like Laplace's atoms, impossible to track and anticipate individually. Yet one can bet on the fact that just as atoms executing a drunkard's walk will eventually get somewhere, so too will accidents eventually occur. Called normal accident theory, Perrow's doctrine describes how that happens - how accidents can occur without clear causes, without those glaring errors and incompetent villains sought by corporate or government commission.