Define the terms precisely: dumber means reduced independent problem-solving capacity. Faster means net output, not keystrokes. The burden is on the other side to prove a skill they never practice doesn't decay. Precedent from calculators is instructive: people lost arithmetic fluency, yet nobody claims that made them better engineers. AI autocomplete short-circuits the very struggle that builds mental models. You type faster, sure. But when the model hallucinates, you lack the debugging instincts to catch it. Net speed collapses. That's not acceleration; that's deferred cost.