CONCEPT
Knowledge Doubling Curve
Fuller's empirical observation that the rate at which human knowledge doubles has accelerated from once per century to once per hours — and AI is both the product and the accelerant.
The knowledge doubling curve is Fuller's empirical tracking of the rate at which human knowledge, measured by various indices, doubled across history. Until 1900, the doubling rate was approximately every century. By World War II, it had compressed to every twenty-five years. By the 1980s, Fuller estimated it at roughly a decade. By 2025, estimates for specialized domains had compressed the doubling rate to hours. The curve has gone vertical, and AI is simultaneously the product of that verticality and its accelerant. Each model trained on the accumulated knowledge of civilization produces outputs that become part of the training data for the next generation of models, creating a feedback loop Fuller's curve anticipated but could not have quantified. The ephemeralization of cognition is not merely fast; it is self-amplifying.
In The You On AI Field Guide
Fuller developed the knowledge doubling observation in Critical Path (1981) by tracking patent filings, scientific publications, and documented technical capabilities across centuries. The exact numbers