In tracing the social changes that occurred as humans moved from hunting and gathering to agriculture to industry, Gellner rejects genetic and teleological explanations and stresses instead the roles of special combinations of circumstances and of cognition. He argues against cultural relativism and contends that human societies have progressed in genuine knowledge, even if at a price.

Despite the triumph of cognition and the abundance of goods offered by industrial production, Gellner warns, coercion still plays a menacing role in modern society. He advises that, though we cannot predict the future, we can understand our options by comprehending the past.