THE REFERENCE LIBRARY
A growing collection of ideas for understanding the world — and your own thinking.
Compare options from several perspectives by assigning outcome utilities, calculating expected utilities, and combining them with weights. The preferred option depends on those judgments and the estimated probabilities.
A structured decision framework that evaluates options across multiple weighted perspectives by assigning utilities and probabilities, computing expected values, and ranking options based on total weighted expected value.
Projects and systems composed of multiple independent steps have a combined probability of success that is the product of each step's probability, often leading to much lower success rates than intuitively expected. This underestimation contributes to cost overruns, delays, and failures in areas from construction to startups.
In a multiplicative calculation, a zero factor makes the product zero. As a practical analogy, this directs attention to essential dependencies whose complete failure could defeat an otherwise sound plan.
Multitracking is the practice of considering multiple options simultaneously to better understand the problem, reduce ego involvement, and improve decision quality.
Multitracking means developing and comparing several options at the same time. It can reveal useful differences, reduce attachment to one proposal, and provide a fallback if a preferred option fails. The aim is a manageable set of meaningful alternatives; adding options also takes effort and can become overwhelming.
Generating multiple distinct options simultaneously, rather than sequentially or as a single choice, leads to markedly better decisions. The wisest decisions often blend the vigilance of a prevention focus with the eagerness of a promotion focus.
Munger’s 25 tendencies form a practical checklist for examining misjudgment. He draws on psychology, business stories, and personal experience, emphasizing how incentives, habits, social pressures, and other influences can reinforce one another. This article outlines the framework rather than reproducing the full talk.
Whitney Tilson’s notes collect Charlie Munger’s remarks at Berkshire Hathaway and Wesco annual meetings. They cover investment judgment, incentives, business ethics, learning, and everyday decisions, alongside Munger’s humor and criticism of professional conventions.
This concept explains how people compare reality to counterfactual alternatives, with some alternatives feeling 'closer' because they involve mutable (easily changed) aspects of an event. It links to philosophical ideas of possible worlds and to linguistic distinctions between presupposition and assertion.
In Caulfield and Wineburg’s Fukushima flowers example, students sometimes accepted a striking photo as proof of toxicity or dismissed it as fake. Both responses skipped investigation of what the real image actually showed.
For equally likely selections, divide the number of qualifying items by the total number of items. For example, if 30% of the jelly beans are red, a uniformly random draw has a 30% chance of selecting red. Mutually exclusive outcomes cannot occur together.
The mystery, therefore magic fallacy occurs when one takes the inability to find a natural explanation for a phenomenon as a reason to accept a magical, supernatural, or fantastic explanation. It is a form of appeal to ignorance, where ignorance of natural causation is mistaken as evidence for supernatural intervention.
Myths are mental patterns that arise first in the mind, then find or create justification in the environment, gaining pseudo-reality as they shape perception and generate new concepts through language.
The mistaken belief that current success or dominance in a population is necessarily evidence of superior evolutionary fitness, ignoring the role of randomness, small sample sizes, and local optima. It is a specific manifestation of the survivorship bias and the law of small numbers applied to evolutionary thinking.
Naïve empiricism is the natural tendency to seek and treat confirming instances as evidence while ignoring disconfirming evidence, leading to overconfidence in our theories and stories.
Naive empiricism treats observed patterns as guarantees about what can happen. Taleb emphasizes an asymmetry for unrestricted universal claims: a reliable counterexample can refute one, while a finite series of confirming observations cannot prove it will always hold.
The misapplication of Darwinian ideas to fields like economics, where people wrongly assume continuous progress and survival of the fittest, ignoring the role of randomness, negative mutations, and regime switches.
Taleb argues that concentrated, interconnected financial networks can look stable while remaining vulnerable to rare, widespread failures. His concern is that shared exposures and dependence on major hubs let a local failure spread through the system.
Naive interventionism is the tendency to intervene and 'do something' even when inaction would be better, often resulting in harm due to unawareness of the break-even point between benefits and harms. Taleb illustrates this with the example of children being recommended tonsillectomies by successive doctors.
Naive realism is the tendency to believe that one's own perspective is objective and that others, if rational, should share it; when they don't, it's due to lack of information, irrationality, or bias.
Naive realism is the tendency to believe that we see the world objectively and that others who disagree are biased, ignorant, or irrational. This bias leads people to overestimate biases in others while remaining unaware of their own subjective influences.
The narcissist fallacy occurs when one falsely assumes that others are thinking about, noticing, or caring about them, projecting their own self-importance onto others' motivations.
Taleb proposes using a written narrative to soften hindsight-driven regret. Writing can help examine what was known at the time, although a coherent account does not establish that the outcome was unavoidable.
Narratives reduce complex information into simpler, more memorable stories, but this can cause people to overestimate the probabilities of events within the story, as seen when readers assign high probabilities to multiple suspects in a detective novel.
The narrative fallacy occurs when a coherent story gives us more confidence in an explanation than the evidence warrants. Retrospective accounts can hide luck, failed alternatives, and missing information, making an outcome seem more predictable than it was.
Taleb’s story of Carlos, an emerging-market bond trader, illustrates the difficulty of separating skill from favorable market conditions. An impressive biography and a successful run can make a compelling explanation without establishing how much of the result came from ability.
Using narrative fragments and small experiments to explore complex situations, uncover hidden insights, and determine direction without premature assumptions.
People tend to unduly narrow their options when making decisions, often due to false constraints or limited perspective. By reframing the question, they can discover many more viable possibilities.
Erikson proposes that Blues and Greens may share a calm, reflective pace, while Reds and Yellows may share an outgoing, fast-moving one. He uses these pairings to discuss potential ease and friction in collaboration.
Natural selection is the process by which traits that improve reproductive success become more common over generations, driving biological evolution. It also provides a broad mental model for society, organizations, and personal life: adapt to environmental pressures.
Darwin's theory of natural selection explains how organisms with helpful traits are more likely to survive and reproduce, leading to the adaptation of populations over successive generations.
Moore’s naturalistic fallacy concerns identifying goodness with a natural property, such as pleasure. Related but distinct problems are deriving an ought from purely descriptive premises and assuming that whatever is natural must be good. Arguments about nature need their ethical premises made explicit.
Taleb argues that localized evolutionary trial and error limits losses, while some large-scale human interventions expose many people to the same potentially catastrophic error. He applies this concern to synthetic life and other technologies that can spread beyond their initial setting.
Taleb uses bricolage, or making do by recombining available parts, to illustrate trial and error. He calls it optionality when failed attempts have limited costs and favorable results can be recognized and exploited for much larger gains.
Harrison argues that near-death accounts do not, by themselves, establish an afterlife. Their emotional force and the sincerity of the storytellers do not rule out dreams, memory errors, or unusual brain states as alternative explanations.
Many people confuse necessary conditions (prerequisites) with sufficient conditions (the full set that guarantees success), overlooking that the gap often involves luck or factors beyond control.
A cognitive distortion where an individual feels an intense need to control situations and others, often driven by a belief that they know best. This leads to overbearing behavior, such as interrupting or taking over tasks, which can frustrate others.
Negating both sides of a conditional does not produce its contrapositive unless their order is also reversed. From if p then q, the valid contrapositive is if not q then not p; if not p then not q does not follow.
To negate a universal implication, identify a case where its condition holds but its conclusion does not. Having privilege, for example, does not imply being white if someone can have another form of privilege.
Negation is how we argue against things, but people often do it badly. Understanding negation helps build logical power by recognizing which statements are equivalent and which constitute true refutations.
The negation of a claim that evidence is sufficient is that the evidence is insufficient. That does not, by itself, establish that the underlying hypothesis is false. Keep this logical distinction separate from the statistical question of how evidence is measured.
With inclusive or, negating A and B gives not A or not B; negating A or B gives not A and not B. The rules describe the truth of compound statements. Applying them to causes requires a justified model of how the factors produce the outcome, and does not by itself settle responsibility.
Negating a statement means declaring it false. For claims on a scale, that can leave many possibilities between the original claim and its polar opposite. Confusing negation with an opposite can turn disagreement into an unnecessarily extreme claim.
Negative advice emphasizes avoiding harmful actions and losses rather than seeking positive gains, and is often more empirically robust. Despite its value, people prefer positive advice and action over inaction, leading to errors in decision-making.
A logical fallacy where a categorical syllogism has a negative conclusion yet both premises are affirmative, violating the rule that any valid syllogism with a negative conclusion must have at least one negative premise.
Systems can become fragile under stress when a small increase in demand leads to disproportionate negative outcomes, often due to bottlenecks. The example of movie theater exits illustrates this negative convexity effect where additional people exiting cause more trauma.
A bias where, for concave functions, the average of the function is less than the function of the average, leading to underestimation of harm from variability. This makes fragile systems more harmful than expected.
A reliable counterexample can refute a universal claim even when many confirming observations cannot establish it. Taleb emphasizes this asymmetry while acknowledging that observations and tests can themselves be mistaken.
When agents receive positive incentives (e.g., bonuses) without bearing downside risk, they are incentivized to maximize the probability of small gains and minimize the probability of observed losses, even if this degrades the total expected return and generates hidden negative skewness—a recipe for catastrophic blowups.
Negativity bias is the tendency to give negative events more attention or weight than positive events of similar intensity. An evolutionary explanation connects this tendency with the value of noticing threats.
Negative information can attract more attention and carry more weight than comparable positive information. The source connects this asymmetry to threat detection and discusses its effects on impressions, relationships, and judgments.
System 1 quickly resolves ambiguous stimuli based on context without conscious awareness, suppressing doubt and alternative interpretations. This cognitive bias leads people to jump to conclusions and remain unaware of the ambiguity that was resolved.
People tend to neglect their past experiences when making predictions, often due to a focus on the future, difficulty extracting relevant instances, and attributions that diminish relevance, especially when past experiences contradict optimistic expectations.
Neomania is the bias towards constantly seeking new versions of technological items, driven by focusing on differences rather than commonalities. The treadmill effect describes how satisfaction from new purchases quickly returns to baseline, fueling a cycle of dissatisfaction and desire for upgrades.
Taleb’s portrait of Nero illustrates a preference for staying in the trading business over maximizing returns. Nero limits losses and avoids exposures he thinks could end his career, accepting lower profits in exchange for reducing the chance of ruin.
Network effects occur when a product or service becomes more useful as more people use it. Growth can attract further users, though congestion or changing community norms can reduce the benefit.
Experts' mental models have many interconnections between components, enabling deeper understanding, while novices have few links due to surface-level knowledge.
The brain's ability to reorganize itself by forming new neural connections throughout life, enabling learning, habit change, and recovery from injury.
Neuroplasticity is the brain’s capacity to change with experience. Focused practice, feedback, and adjustment can help develop a skill or habit; improvement is assessed through what a person can do, rather than assuming repetition guarantees a particular neural change.