When reading about early civilizations, you often come upon the distinction between 'cultures' which seem to be the domain of archaeologists and 'states' which seem to be the domain of historians. Books often talk about 'state formation' as if there is some clear boundary between state and non-state entities but it isn't clear to me at all that this is the case. I can't pinpoint any clear qualitative division. Is there some arbitrary level of population density, or agricultural technology, or writing system sophistication, or authority centralization at which a culture suddenly becomes a state?
The exact definition of a culture is always a hot topic, but for simplicity, we'll say it's the sum complex of a human populations' production. It's broad and inclusive; few things don't fit into culture. A state is explicitly a governing body with centralized control. State formation is the emergence of a political body beyond that of local, small scale tribe-like body or familial organization.