--- name: lindy-effect description: "Activate when: user asks 'should we use this old technology or switch to something newer', 'how do I know if a book is worth reading', 'this institution has been around forever — is that meaningful', 'we should modernize / this time is different', 'how long will this practice / tool / framework last'. Do NOT activate when: the item is perishable or has a deterministic life cycle (humans, hardware, organisms); elimination forces are absent and the old thing survives only due to regulatory lock-in." --- # Lindy Effect ## Overview For **non-perishable items** — ideas, books, technologies, institutions, practices — life expectancy is proportional to current age. The longer something has survived competitive elimination, the longer its expected remaining life. Math: if survival follows a Pareto distribution with α ≈ 1, expected remaining life ≈ current age. Not nostalgia — statistical inference from a track record of passing elimination tests. Composes with [`antifragile`](../antifragile/SKILL.md) (Lindy-survival is the signature of antifragility), [`survivorship-bias`](../survivorship-bias/SKILL.md) (paired warning), [`first-principles`](../first-principles/SKILL.md) (Lindy says *that*; first-principles says *why*), [`switching-costs`](../switching-costs/SKILL.md), and [`chestertons-fence`](../chestertons-fence/SKILL.md). ## When to Use - Choosing a foundational technology / library / framework with high switching cost - Evaluating a long-established practice or institution someone is proposing to discard - Assessing a new methodology being marketed as "modern" or "evidence-based" - Allocating reading time across old vs. new books - Designing institutional partnerships with multi-decade horizons - Deciding which layers of an AI stack to build on time-tested foundations (SQL, Unix, TCP/IP) vs. fast-churning AI frameworks amid the AI adoption hype - Someone says "this has stood the test of time," "we should modernize," "this time is different" **Not when:** item is perishable or has a deterministic life cycle; elimination forces are absent (old institution survives only via regulatory protection); conditions have genuinely changed enough to invalidate survival evidence; decision time-horizon is too short for long-run durability to matter. ## Coaching Novices (Adaptive Front Door) - **Engine mode:** user has a concrete old-vs-new decision → run The Process directly. - **Coach mode:** user unfamiliar or no concrete case → guide step by step. In Coach mode, respond one step at a time. Each [WAIT] is a hard stop — output only that step's question, then stop. 1. One-line: for non-perishable items where elimination forces still operate, prefer the older — its survival is evidence of durability the newer item hasn't yet earned. 2. Check fit: perishable item or absent elimination forces → Lindy doesn't apply. 3. Elicit their case: what's the old item? the new? the domain? > **[WAIT — do not advance until user responds]** 4. Run The Process: non-perishable? elimination forces continuous? Lindy prior? conditions justify this-time-is-different? > **[WAIT — do not advance until user responds]** 5. Close: state the decision with Lindy-prior + conditions that would override it. > **[WAIT — do not advance until user responds]** ## The Process ``` Step 1 — Items: old item (age) / new item (age) / decision / time horizon / switching cost Step 2 — Applicability: non-perishable? | elimination forces operating? | power-law plausible? | conditions changed? Step 3 — Lindy prior: old expected remaining life (≈ age) / new expected remaining life / ratio Step 4 — This-time-is-different: which conditions changed / invalidates survival evidence? / cost if wrong Step 5 — Decision: foundational → lean Lindy; exploration → lean new; document Lindy weight Step 6 — Reversibility (if going against Lindy): reversal plan / reversal signals / monitoring owner ``` ### Output: Lindy-Informed Decision ``` # Lindy-Informed Decision: Items: old (age) / new (age) / time horizon / switching cost Applicability: non-perishable Y/N | elimination forces Y/N | power-law Y/N | conditions changed Y/N Prior: old remaining life / new remaining life / ratio This-time-is-different: claim / evidence / verdict Decision: old/new/hybrid | Lindy weight | override reasoning Reversibility: plan / signals / owner ``` *→ Method in Action: [Goldman 1964, Mandelbrot 1982, Taleb 2012](examples/goldman-1964-mandelbrot-1982-taleb-2012.md)* *→ 2026 lens: [Lindy vs. AI-framework churn in the 2024–2026 tech stack (2024–2026)](examples/lindy-vs-ai-framework-churn-2024-2026.md)* ## Pack: Lindy Effect Application Patterns | Domain | Lindy-stronger choice | Common error | |---|---|---| | Programming languages | C (1972), Python (1991) over 3-year-old languages | Adopting new language for foundational layer | | Databases | PostgreSQL (1996), Oracle (1977) over new graph DBs | Choosing newest for load-bearing tier | | Reading | 100-year-old in-print book over this month's release | Reading only the new; assuming old is irrelevant | | Scientific findings | 50-year replicated finding over new single study | Treating new study as more credible than decades-replicated old finding | | Investment principles | Graham (1934), Bogle (1975) principles over recent strategies | Adopting recent quantitative strategy as foundation | ## Applying It Well - Lindy is a **prior**, not a verdict — it shifts burden of proof to "why new?" without banning new. - Lindy weight is high for load-bearing foundations (high switching cost, long horizon), low for exploration layers. - "This time is different" bears the burden: name *which* conditions changed and *why* that invalidates survival evidence. - Compose with first-principles: Lindy says *that* something works; first-principles says *why* — test whether modern conditions break the mechanism. *→ Primary sources: [references/sources.md](references/sources.md)* ## Common Rationalizations **[D] = designed upfront | [O] = observed in real use. [O] entries are more valuable.** | Fake move | Reality | |---|---| | [D] "It's old, so it's outdated" | Lindy says the opposite: old non-perishables have *more* durability evidence, not less. | | [D] "This time is different" | Reinhart's 800 years: this is rarely as different as claimed. Burden of proof on the change-claim. | | [D] "Modern conditions changed everything" | Some conditions did. Name *which* changed and *whether* that invalidates the survival evidence. | | [D] "New = better" | Empirically false in many domains. Lindy-strong systems outlasted multiple generations of "improvements." | | [D] "We'll switch back if it doesn't work" | Switching costs are non-symmetric. New systems create lock-in that prevents rollback. | | [D] "Tradition isn't a reason" | Long-surviving tradition is statistical evidence — add first-principles, don't dismiss it. | | *→ Add [O] entries here after each real use — paste the actual failure pattern* | *What went wrong and why* | ## Red Flags - An "outdated" technology is being replaced without specific reason beyond age - A new methodology is being adopted because "it's the new standard" - "This time is different" is the primary justification for a major change - The cost of the new (if it fails) is much higher than the cost of staying with the old - The decision-maker has personal career incentive for the new ## Verification - [ ] Lindy-applicability tested (non-perishable, elimination forces, power-law) - [ ] Lindy prior for the old item's continued survival computed or qualitatively estimated - [ ] This-time-is-different claim (if any) specifically articulated and evaluated - [ ] Cost of being wrong about overriding Lindy computed - [ ] If going against Lindy: reversibility plan in place - [ ] Lindy weighting documented in the decision --- *Part of **deciqAI Knowledge Skills** — 225 open-source thinking skills that make rigor executable for AI agents. The same skills power every deciqAI agent, which runs them autonomously to operate your company. **See it run → https://www.deciqai.com/s/lindy-effect** · Built by deciqAI · github.com/deciqAI · Contributions welcome.*