In 1963 the British folklorist Lord Raglan opened a study of the origin of the house with an argument about hats. A generation earlier every man in the West had worn one out of doors, for reasons that seemed self-evident: warm in winter, cool in summer, dry in the rain. Then the custom lapsed, and the hat survived only at weddings and funerals—“going back,” as he put it, “to what was in fact its original function, that of forming part of a ceremonial costume.” What had looked practical had been ceremonial all along. The habit was simply too familiar to examine. His book applies the same reversal to architecture. Houses, the first sentence of his preface claims, “were originally neither shelters nor dwellings but temples, that is to say buildings erected for ritual purposes.”

We explain the first dwellings by appeal to need: shelter is necessary, those who could build sought it, the house follows. Raglan's objection is that a need must be imaginable before it can be felt. “Early man can no more have felt the need of a house than can 18th century man have felt the need for a car,” he wrote.