In one of the most important fragments of the Arcades Project, “On Some Motifs in Baudelaire,” Benjamin contrasts depleted modern experience (Erlebnis) with symbolically rich poetic experience (Erfahrung). He interprets Les Fleurs du mal as reflecting the disintegration of the material world’s “aura,” the symbolic associations that once permitted sacred objects to “return our gaze,” as Benjamin puts it. In his essay on “The Work of Art in the Age of Mechanical Reproduction” (1936) he had already analyzed how modern productive forces robbed artworks of their aura, detaching them from the human traditions out of which they had emerged. The Arcades Project would try to show more subtly how the bourgeois nineteenth century had replaced the aura of the material world with a dream world, a “phantasmagoria” subtly reflecting and compensating for the contradictions of capitalist society. It would be a history of bourgeois delusions.
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In 1935, in return for the Institute’s [Institute for Social Research] support, Benjamin dutifully submitted a clear and well-organized prospectus of his work in progress, which has been translated in Reflections as “Paris, Capital of the Nineteenth Century.” In it he carefully outlined a new kind of social history capable of embracing architecture, manners, dress, interior design, literature, photography, city planning, and much more. Citing Michelet’s maxim that "each age dreams the next," he imagined that this new history would teach us "to recognize the monuments of the bourgeoisie as ruins even before they have crumbled." This short essay has proven enormously influential among contemporary historians, who by now have produced a vast, if dubious, literature on the collective unconscious of the nineteenth century along Benjamin’s lines.
To read through the copious material of the Arcades project, though, is a morbid experience. It seems less a study of the ruins of bourgeois life than the ruins of an intellectual’s last productive years. The thirty-six files of quotations and aphorisms—on fashion, boredom, steel construction, prostitution, the stock exchange, the history of sects, and so on—are occasionally revealing, often funny, but generally repetitive and even dull. Yet they have been treated with all the solemnity due Pascal’s Pensées by academic Benjaminians, who have made heroic exertions to restore this unwritten, unwritable work.