Lindy Effect

Biological Parallel

Survival proves stress-testing. Horseshoe crabs persisted 450 million years across five mass extinctions—surviving what killed 99% of species. Coelacanths endured 65 million years unchanged in deep refugia. Nautilus shells remained unmodified for 500 million years because deep oceans changed slowly. Lungfish survived 380 million years through three mass extinctions by breathing air when waters became anoxic. Time filters for robustness: what persists longest has weathered the widest range of catastrophes. But the Lindy effect has a dark side—Passenger pigeons thrived for millions of years before humans extinguished 5 billion birds in decades. Time tests durability against historical challenges, not novel ones. The mechanism works through successive environmental filtering. Each shift—ice ages, asteroid impacts, oxygen crises—eliminates specialists optimized for old conditions. Generalists with redundant systems persist. Crocodilians survived 95 million years by tolerating temperature extremes (4-38°C), eating anything, and surviving months without food—robustness through versatility. Great white sharks persisted 16 million years as apex predators, adapting to cooling oceans and changing prey. The longer a lineage endures, the more catastrophes it has survived, making past survival a Bayesian prediction of future survival—but only if future challenges resemble historical ones. Invading species extinguish island endemics that survived 10 million years in isolation. Longevity predicts robustness to known stressors, not immunity to novel threats.