THE REFERENCE LIBRARY
A growing collection of ideas for understanding the world — and your own thinking.
A Ulysses contract is a precommitment strategy where past-you binds present-you to rational behavior by raising barriers to irrational actions or lowering barriers to rational ones, creating a decision-interrupt that encourages deliberative thought.
Two variables can be uncorrelated (zero linear correlation) but still strongly related through a nonlinear relationship. Correlation only detects linear associations, not all forms of dependence.
Taleb describes a proposed result about estimating probabilities from samples without prior restrictions on the admissible distributions. The passage raises the problem of model assumptions but does not supply the proof or its precise conditions.
People predicting their affective responses over time often imagine their initial reaction and then adjust for time passage, but tend to undercorrect, leading to a durability bias.
When people are cognitively busy (e.g., self-regulating their own behavior), they are less able to use situational constraint information to correct their dispositional inferences about others, leading to overattribution of dispositions.
Scientific hypotheses can guide inquiry before the available evidence settles between them. Nisbett discusses the role of hunches and cultural context in paradigm changes while rejecting the conclusion that facts are merely arbitrary agreements.
The benefit of an act of scout mindset goes beyond immediate accuracy gains; it reinforces valuable thinking habits that compound over time. In any single instance, these long-term habit improvements are easily overshadowed by the immediate rewards of soldier mindset.
The 2010 Copiapó mining accident shows how formal authority and informal leadership can interact under extreme pressure. The miners developed an underground hierarchy that helped coordinate survival; contact with rescuers introduced new sources of authority and changed that order.
Understanding the perspective of someone with opposing views, through empathy and good-faith engagement, can lead to changing their mind. Acknowledging weaknesses in your own side is key to building trust and facilitating change.
The understanding/acceptance principle treats changes in people’s judgments as evidence in a debate about a reasoning norm. If better understanding brings greater acceptance, confidence in the norm or its application increases; if it does not, that application may need reconsideration. Agreement is a clue, rather than proof of correctness.
The fallacy of undistributed middle occurs when the middle term in a categorical syllogism is not distributed in either premise, rendering the argument invalid because it fails to establish a necessary connection between the premises.
Tragic or challenging events can prompt positive social, economic, and personal changes, including unforeseen improvements and restructuring.
Outperforming untrained people does not establish that a machine detects features humans cannot see. Differences in training or in combining visible cues may explain the result.
Confidently asserting that a theory or hypothesis is true or false even though it cannot possibly be contradicted by observation or experiment, usually without strong evidence or good reasons.
Avoid focusing on a single part of the opponent; instead, adopt an unfixed, broader view to perceive the whole situation and respond naturally. This concept, derived from martial arts, emphasizes looking through the enemy to read intentions and maintain flexibility.
An unforced error is an avoidable mistake that does not result from an opponent forcing the outcome. The idea encourages attention to preventable errors in preparation, judgment, and execution.
In complex socio-technical systems, every interaction and intervention inevitably generates unintended consequences. To manage these, interventions must be small, safe-to-fail, and coupled with dampening strategies, while embracing serendipitous positive outcomes.
Unit bias is the tendency to assume that a single unit or serving (e.g., one plate, one package) represents the optimal or appropriate amount, leading to overconsumption or overuse when units are larger.
Dennett compares Darwin’s idea to a fictional acid that eats through every container. He argues that evolutionary thinking can transform how we understand ethics, art, religion, and consciousness while preserving much of what we value in them.
Darwinian thinking, described as 'universal acid,' challenges traditional top-down design by explaining how mindless, cyclic processes can generate ever-more robust combinations through evolution, leading to complex phenomena like multicellularity, sexual reproduction, language, and culture.
Universal statements like 'All men are sexist pigs' require refutation by finding a single counterexample (existential statement). A joke about three logicians illustrates how individuals can deduce the truth of a universal claim through sequential self-reporting.
Don't reject or accept an idea based solely on its source. Evaluate claims impartially according to preestablished impersonal criteria, regardless of the presenter's personal or social attributes.
Judgments of severity or value can be inconsistent when made in isolation (single evaluation) versus in comparison with other cases (joint evaluation), leading to unjust reversals. This cognitive bias is evident in legal settings, where punitive damages and penalties vary incoherently depending on whether cases are viewed alone or alongside others.
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Unpacking a category into named possibilities can change probability judgments and choices. Naming components can make an event more salient or increase its weight in a decision, even when the stated probabilities stay the same.
When an event is divided into mutually exclusive parts, the probabilities judged separately for those parts can sum to more than the probability assigned to the whole. Support theory calls this subadditivity. The studies discussed here distinguish this unpacking effect from judgments of an event and its complement, which generally sum to one.
The unpacking principle in support theory describes how people assign higher probability to explicit disjunctions (e.g., dying from heart disease, cancer, or other natural causes) than to coextensional implicit disjunctions (e.g., dying from natural causes), demonstrating subadditivity. This cognitive bias affects probability and frequency judgments, increasing with the number of unpacked components.
Unrealistic optimism involves favorable expectations about the future that exceed what the evidence supports, often including lower perceived risks than one’s peers. The research reviewed here found mixed consequences: some optimistic expectations were associated with positive health behaviors rather than the harms researchers anticipated.
People tend to rate their own risk of negative events lower than that of others, a phenomenon known as unrealistic optimism or optimism bias.
People tend to underestimate their personal risk of experiencing negative events, and this optimistic bias is resistant to disconfirming information. Making high-risk individuals salient can paradoxically increase optimism by reinforcing the belief that one is not like them.
The source discusses a logical fallacy in the context of critical thinking but does not name or explain it.
Norm theory proposes that information can remain active in memory after it has been corrected or discounted. The authors use this mechanism to explain belief perseverance and inferences about personal traits drawn from behavior constrained by a situation.
The fallacy of unwarranted assumption occurs when a claim or belief is made with little or no supporting evidence, often taking things for granted without justification. It manifests in stereotypes, loaded questions, and misapplied generalizations, undermining the validity of arguments.
The fallacy of assuming that conversational implicature (what is suggested in everyday speech) is a logical implication (what must be true). For instance, saying 'some are' does not logically guarantee 'some are not', even though it is often implied.
Frames shape how we interpret events, but experience can leave them out of date. Updating a frame means reconsidering the interpretation when new evidence no longer fits.
Taleb criticizes arrangements that let decision-makers collect gains while others bear the losses. He argues that this asymmetry can conceal fragility and that those exercising power should share responsibility for its consequences.
A decision framework that categorizes tasks based on urgency and importance, advocating action on urgent-and-important items and elimination of those that are neither. The concept is illustrated by Bill Gates's decision to drop out of Harvard to pursue a time-sensitive opportunity.
Although checking URLs is important for verifying sources, people often over-rely on top-level domains like .org to judge credibility. In fact, .org domains are not restricted to nonprofits and can be registered by anyone, including hate groups.
Learning, reading, and exploring give adults opportunities to keep using and practicing their mental skills. The author argues for a lifelong habit of curiosity, illustrated by his own reading, travel, and museum visits.
When decision-makers don't act on a problem, it's often because they underestimate its severity. Using concrete external examples (like fines or penalties faced by others) can make the risk feel real and urgent, helping to secure approval for mitigation measures.
Internal audit teams can improve action plans by addressing root causes rather than symptoms, but must balance systemic changes with pragmatic, incremental steps to maintain stakeholder engagement. Using tools like Bowtie and fishbone diagrams helps communicate findings neutrally and build persuasive cases.
Skills and mental abilities weaken when not regularly practiced. To retain rarely used skills, one must engage in continuous practice, akin to a pilot using a flight simulator.
A logical fallacy that occurs when one confuses the word used to describe a thing with the thing itself.
System 1 and System 2 are fictional agents used to describe automatic and effortful cognitive processes. They are not real parts of the brain but useful metaphors that simplify explanations of judgment and choice.
Analogies are used as provocative devices to force new perspectives on a problem. They need not fit perfectly; mismatches can stimulate creative thinking.
A heuristic for assessing the credibility of academic sources by checking how many times an author's work has been cited in Google Scholar, helping to distinguish between well-regarded experts and those with little scholarly impact.
A technique where experts present their views to a small audience of curious nonexperts (e.g., undergraduates) while other experts listen from the sidelines. This allows experts to explain without fear of insulting peers, reducing miscommunication and helping clarify positions.
The phrase 'I believe' signals that a claim is important to one's identity, transforming a description of the world into a self-definition.
Senge uses the subconscious to describe skills and mental activity that operate outside conscious attention. In his account of personal mastery, practice makes complex actions more automatic, while clear goals and an honest view of current circumstances help direct effort. Visualization and reflection support this work alongside training.
A heuristic for quickly understanding the landscape of scholarly debate on a topic by scanning Wikipedia's summary of key positions, using the example of the atomic bomb debate to illustrate how to evaluate the strength of a claim relative to the consensus.
Use Wikipedia to orient yourself, then follow its references to an overview of the debate. Match abbreviated citations to full bibliography entries, choose a source suited to your research question, and check its author and publication before relying on it.
The text explains how to use Wikipedia's references to validate sources, using the example of Sojourner Truth's 'Ain't I a Woman?' speech to illustrate that the famous quote was not originally spoken by her.
Emotions are often blamed for poor decision-making, but combining them with rational analysis can improve decisions, especially when evaluating information.
Utility is the underlying satisfaction or pleasure that drives people's choices, representing the value they expect from a good or service. It explains decisions by weighing benefits and costs, and is subject to diminishing marginal returns.
Utility analysis is a decision-making framework that evaluates choices by considering options, outcomes, and perspectives, quantifying subjective value under uncertainty.
A step-by-step framework for evaluating options across multiple outcome classes by assigning utilities and probabilities, weighting each class, and computing total weighted expected values to rank options.
The utility question asks how valuable each possible outcome would be from a specified person’s perspective. That value must be considered alongside the probability of the outcome when comparing options.
Utility theory distinguishes expected monetary payoff from how much the possible outcomes matter to someone. Ellenberg uses a sure payment, a risky bet, and lottery-ticket combinations to show why financial reserves, potential ruin, and variation in outcomes can change a decision.
A utility tree is a decision-making tool that multiplies possible outcomes by their probabilities to compute expected values, enabling comparison of options and selection of the one with the greatest expected payoff.
A utility tree is a graphical representation that maps out possible outcomes of a decision, their probabilities, and associated utilities (e.g., monetary gains) to calculate expected values, enabling comparison of different choices.