Lindy Effect
"For non-perishable things, every additional day of survival implies a longer remaining life expectancy"
Origin: Named after Lindy's deli in New York; formalized by Benoit Mandelbrot and Nassim Taleb
The Key Insight
Lindy is about filtering - things that survive long periods of exposure to challenges have proven something. But the filtering only works if the challenges in the past resemble challenges in the future. In stable domains (human nature, basic mathematics), Lindy is predictive. In rapidly changing domains (technology, business models), it isn't.
What People Think
Old things that are still around will likely continue - a book that's been in print for 100 years will probably be read for another 100. Age is evidence of robustness.
The Deeper Truth
The Lindy effect is a specific case of power law survival distributions. Unlike biological organisms (which have increasing mortality with age), non-perishable things (ideas, technologies, practices) often have decreasing hazard rates - if they've survived this long, they've proven robust to many challenges. But this only applies to things subject to 'informational' rather than 'physical' aging.
Biological Parallel
Interestingly, some biological systems show Lindy-like properties. Bacterial species that have existed for billions of years are likely to persist. Ancient body plans (arthropod, vertebrate) persist while newer experiments go extinct. Genes that are conserved across many species (like those for basic metabolism) tend to be essential and stable. But individual organisms don't - they have increasing mortality with age.
Business Application
Apply Lindy to: practices and frameworks (old management wisdom that persists probably contains truth), markets (industries that have existed for centuries will probably continue), and human behaviors (people will probably keep wanting what they've always wanted). Don't apply it to: specific technologies (subject to disruption), specific companies (subject to competition), or anything with physical depreciation.
When It Breaks Down
Lindy fails when: (1) the thing is subject to physical wear (companies aren't immortal - they face competition, disruption, and management decay), (2) the environment changes discontinuously (an idea robust for 1000 years can become obsolete overnight), or (3) survival was due to luck rather than robustness. Survivorship bias can masquerade as the Lindy effect.