THE REFERENCE LIBRARY
A growing collection of ideas for understanding the world — and your own thinking.
A deductive argument aims to make its conclusion follow necessarily from its premises. If the argument is valid and the premises are true, the conclusion cannot be false. Inductive arguments instead offer support without that guarantee.
Deduction asks whether a conclusion must follow from its premises; a valid argument can still have false premises. Induction draws conclusions supported, but not guaranteed, by observations. Dialectical approaches examine competing ideas and contradictions to develop a better account of a problem.
Encourages exploring multiple perspectives of a topic to gain deeper understanding, rather than focusing on a single angle.
Default options and automatic enrollment significantly influence retirement savings behavior, leading to higher participation rates when workers are automatically enrolled with an opt-out option rather than having to actively opt in.
People often retain a preset option. In organ-donation systems, that can affect recorded consent, although consent status alone does not determine how many donations or transplants actually occur.
The default heuristic is the tendency to choose the default option or maintain the status quo. It can be sensible due to uncertainty, transaction costs, or past experience, but it can also bias choices when psychological prominence does not align with outcome quality.
Default investment options, such as target-date funds, use inertia to improve retirement savings by reducing poor choices like market timing. They are a nudge that protects investors from common behavioral biases.
Our automatic patterns of thinking and acting are shaped by environment and social cues; by intentionally designing our surroundings and choosing groups with desired behaviors, we can reprogram our defaults for better outcomes without relying solely on willpower.
Defaults are powerful because people tend to take the path of least resistance, often sticking with the option that will prevail if they do nothing. Choice architects can set defaults to nudge behavior, but defaults can be overridden if the outcome is obviously bad and the cost of opting out is low.
Defensive bolstering is a cognitive bias where decision makers engage in self-justifying thinking when accountable to a skeptical audience for irreversible actions, leading to decreased tolerance of dissonant arguments and increased pro-attitudinal thoughts.
Defensive routines protect people from embarrassment or threat by keeping their assumptions from being examined. In teams, they can turn apparent agreement into avoidance. Learning requires making those routines discussable and testing the reasoning behind decisions.
Galef treats defiant words such as proud, unapologetic, and fearless as cues that speakers see their views as embattled. The language can invite a closer look at that self-image, but does not by itself show whether a view is marginal or its supporters face real pressure.
Define the priorities that should govern your time, then create a stop-doing list to make room for them. Reviewing where your time actually goes can reveal the gap between stated priorities and daily work.
Define the problem before choosing a solution. State what is happening, test possible causes, agree on the question to investigate, and identify measures that would show whether the situation improves.
Define the problem before choosing a solution. Give someone responsibility for the problem statement, make the intended outcome and constraints clear, and test the framing with people who understand the situation.
Defining the problem accurately is the critical first step in decision-making. It involves identifying the desired outcome and obstacles, and focusing on root causes rather than symptoms to avoid solving the wrong problem.
A mission states what a person, project, or organization is trying to achieve and why. Clarifying it can guide priorities and resource choices, while leaving room to revise the purpose as circumstances change.
In decision-making, not all variables are equally important. Leaders who identify and clearly communicate the single most important criterion empower their teams to make sound decisions independently, avoiding bottlenecks and ego-driven dependency.
The definist fallacy involves defining a concept in terms of another with which it is not clearly synonymous, often as a persuasive definition, or insisting on a clear definition before discussion. It is a tactic used to make an argument seem more persuasive by using loaded or vague definitions.
Taleb contrasts his experience of small commerce, where new transactions displace old disputes, with the lasting rivalries he encountered in academia. He argues that repeated dealings and small, recoverable mistakes can encourage tolerance.
A critique of the tendency of even expert statisticians to neglect sample size and overinterpret single observations, illustrating the gap between theoretical statistical knowledge and practical reasoning.
Delay in judgement is a lateral thinking technique that involves suspending criticism or evaluation of ideas at various stages, allowing ideas to survive, develop, and potentially lead to solutions that would otherwise be rejected.
When feedback is delayed, individuals or organizations tend to overcorrect or give up because they cannot see the effects of their actions, leading to instability.
Delays are interruptions between actions and their consequences in systems. They often go unrecognized, causing overshoot and instability, but minimizing delays can improve system performance.
The Delphi method gathers expert estimates through repeated questionnaires and anonymous feedback. Participants can revise their views after seeing others’ reasons. The process seeks a considered group estimate; convergence alone does not establish accuracy.
Taleb argues for learning from historical anecdotes while distrusting theories that claim to uncover laws of history. He uses past accounts and simulated futures to develop judgment about randomness.
The tendency to be less willing to spend money when it is in the form of a single large denomination (e.g., a $100 bill) compared to an equivalent amount in smaller denominations (e.g., ten $10 bills).
The invalid inference that if two statements cannot both be true and one is false, the other must be true. Both statements could be false.
A logical fallacy where one incorrectly concludes that if the antecedent of a conditional statement is false, then the consequent must also be false, ignoring other possible conditions.
The fallacy of introducing a third alternative when a genuine binary choice exists, typically to avoid making a difficult decision or answering a direct yes/no question.
Evidence drawn from data can fail because of errors in the data, analytical methods, or interpretation. Check each before relying on a statistical result.
Dependence analysis examines relationships among variables. Banasiewicz organizes causal assessment around sequence, association, possible confounding, and a plausible explanation. Statistical dependence can support an investigation, but it does not by itself show that one factor causes another.
Deprival super-reaction syndrome is a cognitive bias where people irrationally overvalue what they are about to lose, leading them to throw good money after bad rather than cut losses. Combined with over-optimism, it distorts rational decision-making, especially under stress.
Munger uses deprival superreaction to describe an excessive response to losing something valued—or nearly obtaining it and then missing out. He applies the idea to threatened status, ideological conflict, gambling, auctions, and investment decisions.
Bevelin uses deprival syndrome to describe how losing something valued—or facing its loss—can intensify attachment and provoke an excessive response. His examples include threatened benefits, losing investments, near misses, and scarce goods.
Deprival-Superreaction Tendency describes humans' irrational, intense reaction to even small actual or threatened losses of valued possessions, status, or opportunities—a behavior analogous to a dog instinctively biting when food is taken from its mouth.
Taleb argues that systems which adapt to manageable stress can weaken when deprived of it. He applies this idea to institutions and learning, criticizing attempts to suppress all variability.
Description exercises train people to describe the same object or situation from different viewpoints. The aim is to generate useful alternatives and notice what each description emphasizes or leaves out.
Description-dependence is the phenomenon where people's judgments, decisions, and preferences vary based on how a problem or option is described, even when the underlying information is logically equivalent. This cognitive bias challenges the assumption of a single canonical representation and highlights the need for descriptive theories of belief and choice.
In a lateral thinking exercise, a description of a figure must give someone enough detail to draw it. Simply saying what it reminds you of is insufficient. Three valid methods are building from smaller units, comparing it to another figure, and modifying another figure.
Design is a special case of problem solving that requires creativity and open-ended thinking. It uses drawings to commit to specific visual descriptions, revealing alternative approaches and cliché units.
Design requires innovation beyond copying and provides a practical way to apply lateral thinking to creative problems.
A design pattern is an established way to solve a recurring design problem. Looking for patterns in architecture, software, or everyday work can save time and reveal options you might otherwise miss. The useful question is whether the pattern fits the problem and its constraints.
A method using visual and organizational design projects to stimulate lateral thinking by emphasizing variety, function analysis, and avoiding premature criticism. Students design solutions for specific tasks, such as an apple picking machine, to explore multiple approaches and challenge assumptions.
A teaching method where students are given a design task with minimal specifications, encouraging diverse responses and creativity, with discussion focused on comparisons and avoiding criticism.
Practicing design helps develop lateral thinking: try different approaches, challenge assumptions, and suspend critical evaluation temporarily to allow flexibility and variety.
Designing for emergence means intervening in a complex system while it is changing. Work with its existing relationships, try provisional changes, observe the response, and revise the approach as new patterns develop.
Desirability bias occurs when what we want to happen influences what we predict will happen. Adam Grant illustrates it with a forecaster who shifted toward his preferred election outcome, then acknowledged the mistake. Recording assumptions and reasons to change a forecast can help expose this bias.
Desire paths are informal routes worn by repeated use. They often reveal shortcuts or movement patterns that formal paths do not accommodate, giving planners evidence about how people actually use a space.
Erikson portrays Reds as impatient with detail and suggests linking essential checks to the results they want. The practical lesson is to show which details affect an outcome rather than assume a personality label predicts behavior.
The concept illustrates how seemingly simple questions about threat detection become complex when considering specific circumstances such as distance, size, lighting, and atmospheric conditions. It warns against high-level analysis that ignores critical details.
To change your existing mental model, you need to identify which new mental model to adopt. Keeping a thought diary to write down and analyze your thoughts can help reveal problems in your thinking and guide you toward a growth mindset.
Probabilities can be calculated from a specified model or estimated from observations. Jones discusses equal probabilities as a starting assumption when evidence is absent and warns that wishful thinking can distort estimates.
To evaluate quality or worth, specify what you are assessing, why, what information you need, and which standards apply. Elder and Paul distinguish questions answerable within an agreed system from those requiring judgment among competing views.
After identifying root causes of a problem, develop solutions that directly address each root cause, rather than guessing. For complex problems, evaluate multiple potential solutions to select the best one.
A heuristic step in problem-solving that involves applying various techniques such as the five whys, root cause analysis, journey mapping, creative problem-solving, and Hurson's productive-thinking model to generate potential solutions.
Devil's advocacy is a technique that involves deliberately challenging a proposition by seeking evidence for the opposite view to test its validity, often using the same or new evidence to promote objectivity and uncover weaknesses in the primary argument.
The authors argue that promising complete control of blood glucose in type 1 diabetes can encourage self-blame when outcomes vary. Their concern is a cycle of frustration and disengagement, not a claim that self-management cannot influence outcomes.
Identifying root causes (diagnosis) does not guarantee that effective solutions (treatment) will be implemented; stakeholder dynamics, cost-benefit debates, and resistance often block action even after a thorough root cause analysis.
In Bohm’s approach, dialogue lets a group examine assumptions and explore a question before trying to decide. Participants treat one another as colleagues and make their thinking available for scrutiny. Senge distinguishes this exploratory mode from discussion aimed at reaching a decision.