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
I am going to deal with several subjects that, in themselves, are already well recognized as within the province of city planning: subsidized dwellings, traffic, city visual design, analytical methods. These are all matters for which conventional modern planning does have objectives and therefore does possess tactics—so many tactics, so well entrenched, that when their purposes are questioned they are generally justified in terms of the conditions laid down by still other tactics (e.g., We must do this for the purpose of getting the federal loan guarantees). We become the prisoners of our tactics, seldom looking behind them at the strategies.