CONCEPT
Persistence of the Old
Edgerton's empirical law that old technologies almost never disappear when new technologies arrive — they coexist, often for decades, because they remain embedded in systems larger than any single technology.
The persistence of the old is one of the most consistent empirical findings in Edgerton's use-centered history of technology. Across every domain he has examined — transportation, communication, manufacturing, agriculture, healthcare, energy — the pattern recurs with such regularity that he treats it as a structural law rather than an anomaly. Old technologies persist because they are embedded in systems of practice, infrastructure, institutional organization, cultural habit, economic incentive, and accumulated expertise that are larger and more durable than any individual technology. The automobile did not displace the horse for decades after its invention. The radio did not displace the newspaper. The personal computer did not displace the typewriter for years after its introduction. In each case, the displacement narrative was wrong about the timeline and wrong about the completeness of replacement.
In The You On AI Field Guide
Edgerton's documentation of the pattern is exhaustive. There were more horses in the United States in 1928 than in 1888,