https://mentarium.io/ Think clearer. Decide better. Mental models, cognitive biases and decision tools. en https://mentarium.io/mental-models/via-negativa https://mentarium.io/mental-models/via-negativa Via negativa means improving by removing, not adding. Learn where the idea comes from, how to apply it in 5 steps, and when subtraction beats addition. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/thought-experiment https://mentarium.io/mental-models/thought-experiment A thought experiment tests an idea by imagining a scenario and reasoning it through. See Galileo's and Einstein's famous examples and how to run your own. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/theory-of-constraints https://mentarium.io/mental-models/theory-of-constraints Theory of constraints explained: Goldratt's five focusing steps for finding the bottleneck that limits any system, with business, personal and tech examples. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/ten-ten-ten-rule https://mentarium.io/mental-models/ten-ten-ten-rule The 10/10/10 rule asks how you will feel about a choice in 10 minutes, 10 months and 10 years. Learn Suzy Welch's method, examples, and its limits. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/survivorship https://mentarium.io/mental-models/survivorship Survivorship as a mental model: before learning from winners, ask for the graveyard. Abraham Wald's WWII armor analysis, steps and real-world examples. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/sunk-cost https://mentarium.io/mental-models/sunk-cost Sunk cost is money, time or effort you can't get back. Learn the mental model that prices past costs out of a decision, with steps and real examples. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/steelmanning https://mentarium.io/mental-models/steelmanning To steelman is to restate an opposing view in its strongest form before you respond. Learn steelman vs strawman, Rapoport's rules and a 5-step method. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/second-order-thinking https://mentarium.io/mental-models/second-order-thinking Second order thinking asks "and then what?" to see the consequences of consequences. Learn the steps, real examples and how it beats first-level thinking. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/reversible-decisions https://mentarium.io/mental-models/reversible-decisions Two-way door decisions can be undone; one-way doors cannot. Learn Bezos's Type 1 vs Type 2 rule and how to match your decision speed to reversibility. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/regret-minimization-framework https://mentarium.io/mental-models/regret-minimization-framework The regret minimization framework asks which choice your 80-year-old self would regret least. Learn how it works, where it fails, and how to use it well. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/probabilistic-thinking https://mentarium.io/mental-models/probabilistic-thinking Probabilistic thinking means reasoning in odds instead of certainties. Learn how to estimate, update and decide better when you can't know the outcome. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/pre-mortem https://mentarium.io/mental-models/pre-mortem A pre mortem asks your team to imagine the project has already failed and explain why. Learn Gary Klein's method, step by step, with examples and pitfalls. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/parkinsons-law https://mentarium.io/mental-models/parkinsons-law Parkinson's law says work expands to fill the time available. Learn its origin, how to use tighter deadlines well and when the law backfires, with examples. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/pareto-principle https://mentarium.io/mental-models/pareto-principle The Pareto principle says a few causes drive most results. Learn where the 80/20 rule comes from, how to use it, and where it misleads you. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/opportunity-cost https://mentarium.io/mental-models/opportunity-cost Opportunity cost is the value of the best option you give up when you choose. See the definition, how to calculate it, examples and the common mistakes. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/occams-razor https://mentarium.io/mental-models/occams-razor Occam's razor says to prefer the explanation with the fewest assumptions. Learn what it really means, where it comes from, examples and where it fails. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/margin-of-safety https://mentarium.io/mental-models/margin-of-safety Margin of safety means leaving room for being wrong. See where the idea comes from, how investors and engineers use it, and how to apply it to your life. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/map-is-not-the-territory https://mentarium.io/mental-models/map-is-not-the-territory The map is not the territory means every model, plan or metric is a simplification of reality. Learn its origin, how to use it and where maps mislead. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/lindy-effect https://mentarium.io/mental-models/lindy-effect The Lindy effect says the longer a non-perishable idea or technology has survived, the longer it is likely to last. Learn Taleb's version, uses and limits. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/leverage https://mentarium.io/mental-models/leverage Leverage mental model: how small inputs create large outputs through labor, capital, code and media. Learn where to find it, use it and avoid its risks. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/inversion https://mentarium.io/mental-models/inversion The inversion mental model solves problems backwards: ask what would guarantee failure, then avoid it. Steps, examples and Munger's famous version. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/incentives https://mentarium.io/mental-models/incentives Incentives drive behavior more than intentions do. Learn the incentives mental model, Munger's rule, the cobra effect and how to design rewards that work. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/hicks-law https://mentarium.io/mental-models/hicks-law Hick's law says decision time grows with the number of choices. Learn the formula, where it applies, what choice overload research shows and how to use it. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/hanlons-razor https://mentarium.io/mental-models/hanlons-razor Hanlon's razor says never attribute to malice what can be explained by mistakes or carelessness. Learn its origin, how to use it and when it fails. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/five-whys https://mentarium.io/mental-models/five-whys The 5 Whys finds a problem's root cause by asking why until you reach a fixable process. Learn Toyota's method, a worked example, and the mistakes to avoid. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/first-principles-thinking https://mentarium.io/mental-models/first-principles-thinking First principles thinking breaks a problem down to what you know is true, then rebuilds it. Learn the steps, real examples and the mistakes to avoid. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/feedback-loops https://mentarium.io/mental-models/feedback-loops Feedback loops explained: how reinforcing and balancing loops drive growth, stability and collapse, and how to use systems thinking in work and life. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/expected-value https://mentarium.io/mental-models/expected-value Expected value weighs each outcome by its probability to compare choices. Learn the formula, worked examples, and when maximizing expected value goes wrong. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/eisenhower-matrix https://mentarium.io/mental-models/eisenhower-matrix The Eisenhower matrix sorts tasks by urgency and importance into four boxes: do, schedule, delegate, delete. Learn how to use it and where it falls short. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/cynefin-framework https://mentarium.io/mental-models/cynefin-framework The Cynefin framework sorts problems into clear, complicated, complex and chaotic domains, each needing a different response. Learn the domains with examples. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/compounding https://mentarium.io/mental-models/compounding Compounding is growth that builds on its own past growth. See how the mental model works for money, skills, relationships and reputation, with examples. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/circle-of-competence https://mentarium.io/mental-models/circle-of-competence Circle of competence means knowing where your real expertise ends. Learn Buffett's idea, how to map your own circle and the mistakes that push you outside it. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/chestertons-fence https://mentarium.io/mental-models/chestertons-fence Chesterton's fence says don't tear down a rule or system until you know why it was built. Learn the original parable, how to apply it and when to ignore it. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/base-rates https://mentarium.io/mental-models/base-rates The base rate fallacy is ignoring how common something is when judging a specific case. Learn the taxicab problem, the math, and how to use base rates well. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/mental-models/antifragility https://mentarium.io/mental-models/antifragility Antifragile means gaining from shocks, not just surviving them. Learn Taleb's fragile, robust, antifragile triad and how to build antifragility in 5 steps. Mental Models Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/iq/what-is-an-iq-test https://mentarium.io/iq/what-is-an-iq-test IQ test definition: a standardized test that ranks reasoning ability against your age group. Its history from Binet to Wechsler, and what it misses. IQ Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/iq/iq-test-scores https://mentarium.io/iq/iq-test-scores IQ test scores explained: why your number is really a range, how standard error and confidence intervals work, retest effects, and online vs clinical tests. IQ Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/iq/iq-scale https://mentarium.io/iq/iq-scale The IQ scale explained: every IQ range with its Wechsler label, the share of people in each band, and percentiles for 70, 85, 100, 115, 130 and 145. IQ Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/iq/einstein-iq https://mentarium.io/iq/einstein-iq What was Einstein's IQ? He never took an IQ test, and the popular 160 figure is a modern guess. Where it came from and what we actually know. IQ Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/iq/average-iq-usa https://mentarium.io/iq/average-iq-usa The average IQ in the USA is 100 because US samples norm the Wechsler and Stanford-Binet tests. What that means, and why country rankings mislead. IQ Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/iq/average-iq https://mentarium.io/iq/average-iq The average IQ is 100 by definition, at every age. Here is why, what the Flynn effect changed, and what IQ data by country and by job can and can't tell you. IQ Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/decision-making/mental-models-for-programmers https://mentarium.io/decision-making/mental-models-for-programmers Mental models for programmers: Chesterton's fence, Gall's law, YAGNI, five whys and 8 more thinking tools for debugging, design and incident reviews. Decision Making Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/decision-making/mental-models-for-investors https://mentarium.io/decision-making/mental-models-for-investors Mental models for investors: 12 thinking tools, from margin of safety to base rates, that help you judge risk and avoid the classic mistakes. No hot tips. Decision Making Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/decision-making/mental-models-for-entrepreneurs https://mentarium.io/decision-making/mental-models-for-entrepreneurs Mental models for entrepreneurs: 12 thinking tools for pricing, hiring, product and risk, each with how it applies when you are building a company. Decision Making Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/decision-making/how-to-make-a-hard-decision https://mentarium.io/decision-making/how-to-make-a-hard-decision How to make a hard decision when you're stuck: find out why it's hard, size it, name the values in conflict, shrink it into a test, set a deadline and commit. Decision Making Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/decision-making/decision-matrix https://mentarium.io/decision-making/decision-matrix A decision matrix scores options against weighted criteria. Get the template, a full worked example, and the cases where the method quietly fails. Decision Making Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/decision-making/decision-making-process https://mentarium.io/decision-making/decision-making-process The decision making process in 7 practical steps: frame it, size it, map options, gather what matters, stress-test, commit with a prediction, and review. Decision Making Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/decision-making/decision-journal https://mentarium.io/decision-making/decision-journal A decision journal records your reasoning, prediction and confidence before the outcome. How to keep one, what to write, when to review, plus a free template. Decision Making Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/critical-thinking/logical-fallacies https://mentarium.io/critical-thinking/logical-fallacies Logical fallacies explained: 29 common fallacies grouped by type, each with a plain definition and an example, plus a summary table you can keep. Critical Thinking Fri, 30 Oct 2026 00:00:00 -0000 https://mentarium.io/critical-thinking/critical-thinking-skills https://mentarium.io/critical-thinking/critical-thinking-skills Critical thinking skills you can practice: 9 core skills, from analyzing arguments to updating beliefs, each with a short exercise you can do this week. Critical Thinking Fri, 30 Oct 2026 00:00:00 -0000