To build a folly is essentially to do something a second time, something at an inopportune moment. That something is always the memory of something forgotten, about which we can paradoxically say "There it is again."
Follies were misunderstood, purposeless constructions. They were often only small, extravagant gestures in a garden, easily whisking off the imagination to distant lands, a sort of time capsule built to awaken the memory and induce surprise in passers-by. They marked locations, organized secondary paths in a park, or simply predicted the arrival of better times—a demarcation, a sacred spot, a mysterious trail, a hill whose tragic rocky nature begged for a tower, a party, or the arrival of summer.
“It is demonstrably true that things cannot be other than as they are. For, everything having been made for a purpose, everything is necessarily for the best purpose.” — Professor Pangloss
The Situationists were also practitioners of a special urban-analytic walking style, the dérive—the “drift”—which Debord described as “a technique of transient passage through varied ambiences. The dérive entails playful-constructive behavior and awareness of psychogeographical effects; which completely distinguishes it from the classical notions of the journey and the stroll.” “In a dérive,” Debord deadpans, “one or more persons during a certain period drop their usual motives for movement and action, their relations, their work and leisure activities, and let themselves be drawn by the attractions of the terrain and the encounters they find there."
The dérive joins the free association of surrealism, the LSD of hippiedom, and cinematic montage as tactics for overcoming the fixity of received ideas of order and logic.
By putting progress through the city into a state of constant indeterminacy, it represents a schooled “style” of being lost.