What we’re looking for, then, as we trace processes that led to particular structures, is the point at which these processes took a distinctive, or abnormal, or unforeseen course. We’re searching for phase transitions, for punctuations in some existing equilibrium, for an exceptional event that reflected general conditions but that could not have been predicted from them.23 Or, as Aristotle put it in the Poetics, for those moments “when things come about contrary to expectation but because of one another.”24 How, though, do we know what the expectations prior to the event may have been?
