100 Mental Models

Start with basic premises that can be justified, then reason toward a conclusion instead of merely copying an existing solution.

Use and limitsCheck the premises too: calling an assumption a first principle does not make it true.

Aristotle, Posterior Analytics, Book I.

Consider an action’s indirect consequences, including other people’s responses and effects that emerge over time.

Use and limitsCompare plausible chains of consequences; do not treat a compelling story as a reliable forecast.

Reverse the question: instead of asking only how to succeed, ask what would cause failure and how those conditions could be avoided.

Use and limitsAvoiding failure helps identify constraints but does not, by itself, define a successful strategy.

Charles T. Munger, Poor Charlie’s Almanack — Stripe Press edition

When explanations account for the evidence comparably well, prefer one that introduces fewer unnecessary assumptions.

Use and limitsSimplicity is a guide, not proof. A simpler explanation can still be wrong.

Stanford Encyclopedia of Philosophy, “Simplicity.”

Before attributing an unwelcome outcome to malice, consider error, misunderstanding, missing information, or poorly designed processes.

Use and limitsThis is an informal rule of thumb, not evidence that malicious behavior is absent.

Compare options against explicit criteria. Assign weights, score each option, and calculate weighted totals to make trade-offs visible.

Use and limitsTest whether different weights change the ranking. Numbers do not remove subjective judgments.

ASQ, Decision Matrix

A relatively small share of causes may account for a large share of observed outcomes. Rank contributions before deciding where to focus.

Use and limitsThe 80/20 ratio is a heuristic, not a fixed law or a reason to ignore important minority cases.

Joseph M. Juran, Quality Control Handbook.

A sunk cost has already been incurred and cannot be recovered. Letting that cost justify further spending can distort a new decision.

Use and limitsCompare future costs and benefits. Recoverable assets and future switching costs still matter.

Arkes & Blumer (1985), The psychology of sunk cost

People may search for, interpret, or remember evidence in ways that favor an existing belief.

Use and limitsState what evidence would change your mind and actively examine competing explanations.

Peter C. Wason, “On the Failure to Eliminate Hypotheses in a Conceptual Task” (1960).

People sometimes judge frequency or likelihood by how easily examples come to mind. Vivid or recent experiences can therefore distort estimates.

Use and limitsCompare memorable examples with representative data and base rates.

Tversky & Kahneman (1974), Judgment under Uncertainty: Heuristics and Biases

An initial number or reference point can influence a later estimate, even when its relevance is limited.

Use and limitsDevelop an independent estimate before considering another person’s proposed figure.

Tversky & Kahneman (1974), Judgment under Uncertainty: Heuristics and Biases

Different presentations of equivalent outcomes can change preferences, especially when choices are described as gains or losses.

Use and limitsRestate the same choice in multiple ways and check that probabilities and consequences remain identical.

Tversky & Kahneman (1981), The framing of decisions and the psychology of choice

When each period’s gain is added to the base for the next period, growth compounds. Starting with an amount P and a constant rate r, the amount after n periods is P(1+r)^n.

Use and limitsPositive exponential growth has no mathematical inflection point. Learning and relationships do not automatically follow this formula.

A system’s outputs can influence its future behavior. Reinforcing feedback amplifies change; balancing feedback counteracts it.

Use and limitsTrace the actual connections and delays. Positive feedback does not mean beneficial feedback.

Åström & Murray, Feedback Systems — author-hosted textbook

System performance can be limited by a constraint. Identify it, improve its use, align other activities, increase its capacity where appropriate, and reassess.

Use and limitsImproving a nonconstraining activity may not improve total output; the constraint can move.

Goldratt Research Labs, Introduction to the Theory of Constraints

Some systems change sharply after a threshold is crossed because feedback or interactions alter the system’s behavior.

Use and limitsA social tipping point is not automatically a thermodynamic phase transition; thresholds require evidence.

Thomas C. Schelling, Micromotives and Macrobehavior (1978).

A product’s value to a user can depend on the number or type of other users, either on the same side or another side of a platform.

Use and limitsMore users can also create congestion or lower quality. Network effects do not guarantee monopoly.

Michael L. Katz and Carl Shapiro, “Network Externalities, Competition, and Compatibility” (1985).

Past choices can shape current options through switching costs, accumulated skills, complementary investments, or self-reinforcing adoption.

Use and limitsHistory matters, but persistence alone does not prove inefficiency or impossibility of change.

Paul A. David, “Clio and the Economics of QWERTY” (1985).

Interactions among components can produce patterns at the system level that are not obvious from examining each component in isolation.

Use and limitsIdentify the interaction rules; “emergence” is a description, not a substitute for an explanation.

Philip W. Anderson, “More Is Different” (1972).

Evolutionary success is relative to a changing environment that includes other evolving organisms. Maintaining a relative position may require continued adaptation.

Use and limitsIts application to business is an analogy, not a biological proof that constant expansion is necessary.

Leigh Van Valen, “A New Evolutionary Law” (1973).

Changes to rules, information flows, goals, or feedback structures may affect a system more deeply than adjustments to a single parameter.

Use and limitsInfluence depends on context; apparently powerful interventions can have unintended consequences.

Donella Meadows, Leverage Points: Places to Intervene in a System

The total entropy of an isolated system does not decrease. Local decreases are possible when accompanied by compensating changes in the surroundings.

Use and limitsOrganizational disorder is a metaphor; thermodynamics does not prove that teams inevitably deteriorate.

OpenStax, University Physics Volume 2, §4.6 Entropy

A competitive market model relates quantities buyers demand and sellers supply to price. Equilibrium is where those quantities coincide.

Use and limitsDistinguish movement along a curve from shifts of the curve. Market power and institutions can alter outcomes.

Alfred Marshall, Principles of Economics (1890).

An actor has a comparative advantage in an activity when its opportunity cost is lower than another actor’s, even if its absolute productivity is lower.

Use and limitsPotential gains from specialization do not imply equal gains or eliminate adjustment costs.

David Ricardo, On the Principles of Political Economy and Taxation (1817), chapter 7.

The opportunity cost of a choice is the value of the best feasible alternative that must be forgone.

Use and limitsCompare realistic alternatives, not every imaginable benefit; time and other scarce resources also count.

OpenStax, Principles of Economics 3e, Chapter 2: Choice in a World of Scarcity

In the standard one-shot game, each player has an incentive to defect, yet mutual defection leaves both worse off than mutual cooperation.

Use and limitsRepeated interaction, communication, and enforceable agreements change the problem; not every conflict is a prisoner’s dilemma.

Robert Axelrod, The Evolution of Cooperation (1984).

At a Nash equilibrium, no player can improve their payoff by changing strategy alone while the other players’ strategies remain fixed.

Use and limitsAn equilibrium need not be fair, efficient, unique, or the outcome people actually reach.

John Nash (1951), Non-Cooperative Games

In a zero-sum game, one player’s gain is offset by another’s loss. Positive-sum outcomes allow the participants’ combined payoff to increase relative to a baseline.

Use and limitsSpecify the participants, payoff measure, and baseline; cooperation can still distribute gains unevenly.

John von Neumann and Oskar Morgenstern, Theory of Games and Economic Behavior (1944).

Under a common preference assumption, each additional unit consumed provides less extra satisfaction than the previous unit, other things equal.

Use and limitsThis is an assumption used in models, not a universal income threshold for happiness.

William Stanley Jevons, The Theory of Political Economy (1871).

When users share a resource and each bears only part of the cost of extraction, individually attractive choices can lead to overuse.

Use and limitsOveruse is not inevitable. Community rules, monitoring, and other institutions can support collective management.

Elinor Ostrom (2009), Beyond Markets and States — Nobel lecture

Rewards, penalties, and rules influence what people choose to do. A measure used for rewards can redirect effort toward improving that measure.

Use and limitsCheck for gaming, neglected tasks, and effects on intrinsic motivation rather than assuming more reward is always better.

Steven Kerr (1975), On the Folly of Rewarding A, While Hoping for B

One party may know more than another about quality, intentions, or behavior, affecting trade and contractual arrangements.

Use and limitsDistinguish adverse selection before agreement from moral hazard after agreement; information gaps do not always prevent trade.

George A. Akerlof (1970), The Market for “Lemons” — publisher record

Maslow proposed that human motivation involves physiological, safety, belonging, esteem, and self-actualization needs, with differences in their relative priority.

Use and limitsDo not turn this into a rigid staircase: needs can coexist, and the original account allowed exceptions.

A. H. Maslow (1943), A Theory of Human Motivation

Expectations can influence how people are treated, and that treatment may affect their performance. The pathway involves behavior, not wishes alone.

Use and limitsEffects depend on context and evidence; high expectations do not guarantee improved results.

Robert Rosenthal and Lenore Jacobson, Pygmalion in the Classroom (1968).

In the original studies, low performers on particular tasks substantially overestimated their relative performance; limitations in self-assessment were part of the proposed explanation.

Use and limitsIt is not a license to label people unintelligent, nor a universal confidence curve for learning.

Kruger & Dunning (1999), Unskilled and unaware of it — original research abstract

Relative to a reference point, a loss may carry more psychological weight than an equivalent gain.

Use and limitsThe strength of this pattern varies; avoid asserting a universal two-to-one ratio.

Kahneman & Tversky (1979), Prospect Theory: An Analysis of Decision under Risk

An overall favorable or unfavorable impression can spill over into judgments about particular qualities.

Use and limitsEvaluate each criterion with relevant evidence; attractiveness or reputation does not establish unrelated abilities.

Edward L. Thorndike, “A Constant Error in Psychological Ratings” (1920).

People may align judgments or behavior with a group because they seek acceptance or believe the group has useful information.

Use and limitsDistinguish informational learning from pressure to agree; agreement alone does not establish accuracy.

Solomon E. Asch, “Opinions and Social Pressure” (1955).

Observers may overemphasize personal dispositions and underestimate situational influences when explaining another person’s behavior.

Use and limitsExamine constraints and incentives without assuming that individual responsibility is irrelevant.

Lee Ross, “The Intuitive Psychologist and His Shortcomings” (1977).

An analysis can be misleading when it includes only cases that survived a selection process and omits failures or other excluded cases.

Use and limitsDefine the original population and the selection process before generalizing from visible successes.

People may credit successes to their own qualities while attributing failures to external circumstances.

Use and limitsApply the same evidential standard to favorable and unfavorable outcomes.

Dale T. Miller and Michael Ross, “Self-Serving Biases in the Attribution of Causality: Fact or Fiction?” (1975).

After learning an outcome, people may perceive it as more predictable than it appeared beforehand.

Use and limitsRecord predictions and reasoning before the outcome; memory alone is an unreliable audit trail.

Fischhoff, Hindsight not equal to foresight — reprint of the 1975 paper

Inconsistency among beliefs, behavior, or commitments can create discomfort and motivate attempts to restore consistency.

Use and limitsResolution may involve changing behavior, changing a belief, or rationalizing; inconsistency does not guarantee honest correction.

Leon Festinger, A Theory of Cognitive Dissonance (1957).

The Zeigarnik effect refers to the proposed tendency to recall interrupted tasks better than completed ones. It was reported in early experiments, but later findings have been inconsistent.

Use and limitsA 2025 meta-analysis did not find a reliable general memory advantage for interrupted tasks. Do not treat leaving work unfinished as a proven way to improve recall.

Ghibellini & Meier (2025), Interruption, recall and resumption: a meta-analysis of the Zeigarnik and Ovsiankina effects

For independent, identically distributed observations with a finite mean, the sample average converges to the expected value as sample size increases.

Use and limitsIt does not predict the next outcome or make a losing bet profitable through repetition.

Hossein Pishro-Nik, Introduction to Probability, Statistics, and Random Processes, §7.1.1

For evidence E with P(E) > 0, Bayes’ theorem relates a hypothesis’s posterior probability to its prior probability and the likelihood of that evidence: P(H given E) = P(E given H)P(H)/P(E).

Use and limitsCheck base rates and evidence quality; a precise calculation can still rely on poor assumptions.

Thomas Bayes, “An Essay towards Solving a Problem in the Doctrine of Chances” (1763).

The normal distribution is a symmetric, bell-shaped probability distribution described by a mean and a standard deviation.

Use and limitsNot all data are normal. Check skew, tails, and the process generating the observations.

Carl Friedrich Gauss, Theoria Motus (1809).

In a power-law tail, the probability of very large values declines as a power of size rather than exponentially.

Use and limitsDo not infer a power law from a few large observations or a roughly straight log-log plot.

Clauset, Shalizi & Newman, Power-law distributions in empirical data

When repeated measurements are imperfectly correlated, unusually extreme observations tend to be followed by observations closer to the mean.

Use and limitsThis is a statistical selection effect, not a force that reverses every trend or proves an intervention worked.

Francis Galton, “Regression towards Mediocrity in Hereditary Stature” (1886).

Probability models describe uncertain outcomes. Random variation can produce clusters and streaks that look meaningful even without a stable underlying pattern.

Use and limitsDistinguish unpredictable outcomes from missing information and from changes in the process itself.

Hossein Pishro-Nik, What Is Probability?

Expected value is the probability-weighted average of possible outcomes: E[X] = Σ pᵢxᵢ for a discrete variable.

Use and limitsIt is not a guaranteed outcome; variability, ruin risk, and personal constraints may also affect a decision.

Hossein Pishro-Nik, Expectation

Permutations count arrangements where order matters; combinations count selections where order does not. For selection without replacement, n choose k = n!/[k!(n−k)!].

Use and limitsSpecify whether order and repetition matter before choosing a formula.

People may expect small samples to represent a population much more closely than sampling variability permits.

Use and limitsThis names a mistaken intuition, not a mathematical law that small samples are reliable.

Tversky and Kahneman, “Belief in the Law of Small Numbers” (1971).

For a repeated binary bet with net odds b and win probability p, the unconstrained Kelly fraction is f* = p − (1−p)/b. It maximizes expected logarithmic wealth under the model’s assumptions.

Use and limitsUnknown probabilities, correlated bets, and drawdowns matter. This formula does not prescribe how much of a life or career to risk.

J. L. Kelly Jr. (1956), A New Interpretation of Information Rate — publisher record

A fission chain reaction is critical when each generation of reactions just sustains the next. Critical mass is the minimum mass needed to sustain the chain reaction under specified conditions; it depends on composition, geometry, and surroundings.

Use and limitsIn social or business contexts, “critical mass” is an analogy for a threshold, not a universal numerical constant.

U.S. Nuclear Regulatory Commission, Critical Mass

In an inertial reference frame, an object maintains constant velocity unless acted on by a net external force.

Use and limitsOrganizational inertia is an analogy; habits and institutional constraints need their own explanations.

OpenStax, University Physics Volume 1, §5.2 Newton’s First Law

A lever trades force against distance through the relationship between force and its moment arm.

Use and limitsMechanical advantage does not create energy; financial leverage is a different concept with additional risk.

Archimedes, On the Equilibrium of Planes.

Thermodynamics describes energy transfer, equilibrium, and entropy. The first law expresses energy conservation; the second constrains which processes can occur spontaneously.

Use and limitsThese are physical laws, not direct proofs about effort, wealth, or organizational performance.

OpenStax, University Physics Volume 2 — thermodynamics chapters

A safety margin provides capacity beyond an expected requirement; redundancy provides additional components or paths that can maintain a function if one fails.

Use and limitsThey address different risks. Shared dependencies can defeat apparently independent backups.

A failure in one component can transfer load or disrupt dependencies, causing additional failures elsewhere in the system.

Use and limitsMap dependencies and containment measures; a chain of events is not necessarily a self-sustaining reaction.

Charles Perrow, Normal Accidents (1984).

An oscillating system can respond strongly to periodic forcing near one of its natural frequencies; damping influences the response.

Use and limitsCoordinated teamwork is only a metaphorical comparison, not evidence of physical resonance.

OpenStax, University Physics Volume 1 — index entry for standing waves and resonance

Contact forces can oppose relative sliding or impending sliding between surfaces. Friction can impede motion but also enables grip and traction.

Use and limitsIn processes, some checks add useful protection; removing every “friction” is not always desirable.

OpenStax, University Physics Volume 1, §6.2 Friction

Velocity is the rate of change of position; acceleration is the rate of change of velocity. They describe different aspects of motion.

Use and limitsFor business analogies, define whether you mean a level, a first difference, or a growth rate.

The laws of physics have the same form in all inertial reference frames. Measurements must be interpreted within a specified frame.

Use and limitsThis does not mean every opinion is equally true or that factual truth is merely subjective.

Albert Einstein, “On the Electrodynamics of Moving Bodies” (1905).

Heritable differences that affect survival and reproduction can change the frequencies of traits in a population across generations.

Use and limitsSelection has no foresight and does not imply moral superiority or inevitable progress.

Charles Darwin (1859), On the Origin of Species — first edition

A species’ niche concerns the conditions and resources under which it can persist and its relationships with other organisms.

Use and limitsA business niche is an analogy; commercial opportunities require evidence about customers and competition.

OpenStax, Biology 2e, §45.6 Community Ecology

Symbiosis describes close, persistent relationships between different species. Depending on usage, it includes mutualism, commensalism, and parasitism.

Use and limitsDo not equate all symbiosis with mutual benefit; specify who benefits and who bears costs.

OpenStax, Biology 2e, §45.6 Community Ecology

In humans and other jawed vertebrates, innate and adaptive immune mechanisms work together to recognize and respond to biological threats.

Use and limitsOrganizational “immunity” is a metaphor. Treating every unfamiliar idea as a threat can obstruct learning.

Charles A. Janeway Jr. et al., Immunobiology.

Inheritance transmits biological information across generations; mutation and recombination contribute to variation on which evolutionary processes can act.

Use and limitsVariation is not generally produced because an organism needs a particular improvement.

OpenStax, Biology 2e, §18.1 Understanding Evolution

An evolutionary adaptation is a heritable trait shaped by selection that contributes to fitness in a particular environment.

Use and limitsDistinguish evolutionary adaptation from an individual’s acclimatization, learning, or intentional planning.

Charles Darwin (1859), On the Origin of Species — first edition

The r/K framework contrasted life-history strategies associated with rapid population increase and persistence near carrying capacity.

Use and limitsIt is a simplified historical model, not a universal two-type classification of species or companies.

Eric R. Pianka (1970), On r- and K-Selection

An ecosystem includes organisms, their nonliving environment, and flows of energy and materials linking them.

Use and limitsA business ecosystem is an analytical analogy; commercial relationships do not obey every ecological mechanism.

OpenStax, Biology 2e, §46.1 Ecology of Ecosystems

Strategy can involve concentrating limited resources on an important objective rather than distributing them evenly across every possible activity.

Use and limitsConcentration can improve local strength while increasing exposure elsewhere; military reasoning does not transfer automatically to business.

Carl von Clausewitz, On War (1832).

Early entrants may gain through learning, scarce resources, or switching costs, but may also bear development costs and uncertainty that later entrants avoid.

Use and limitsTiming alone does not determine success; identify a mechanism that can preserve an advantage.

Lieberman & Montgomery (1988), First-mover advantages — research article

Sun Tzu emphasizes understanding both one’s own position and the opponent’s. In decision-making, this encourages checking capabilities, constraints, and likely responses.

Use and limitsUse accurate, current information about both sides. Military competition is only one setting; professional relationships may also require cooperation and shared goals.

Sun Tzu, The Art of War — Lionel Giles’s English translation (1910)

Preserve readiness and choose a favorable moment instead of exhausting resources through poorly timed action.

Use and limitsWaiting has an opportunity cost. This Chinese strategic maxim is not a universal argument for passivity.

Thirty-Six Stratagems (三十六计), “以逸待劳.”

Liddell Hart’s strategic approach emphasizes unsettling an opponent’s position and expectations rather than relying exclusively on a direct frontal contest.

Use and limitsIndirect action is not always appropriate; goals, constraints, and the opponent’s response remain decisive.

B. H. Liddell Hart, Strategy (1954).

Breaking a difficult problem into smaller subproblems can make analysis and coordination more manageable.

Use and limitsAccount for interactions between subproblems and how their results will be combined. In strategy, “divide and conquer” can also mean separating an opponent’s forces; that is a different idea.

Participants with different resources or capabilities may compete on different dimensions rather than matching one another directly.

Use and limitsAn unconventional approach is not automatically effective; test its mechanism and constraints.

Depth provides room, time, reserves, or alternative positions that allow a system to absorb setbacks without losing all options.

Use and limitsIn business, define the actual reserve or alternative rather than using “depth” as a vague synonym for strength.

The Peter Principle proposes that promotion based on success in a current role can place people in roles requiring different skills they do not possess.

Use and limitsIt began as a satirical management proposition, not a law that everyone inevitably becomes incompetent.

Laurence J. Peter and Raymond Hull, The Peter Principle (1969).

This informal maxim encourages anticipating ways a plan or system could fail rather than assuming favorable conditions.

Use and limitsA possible failure is not necessarily inevitable; assess probability, consequences, and safeguards.

Parkinson’s satirical observation links the scope and duration of work to the time and bureaucracy available for it.

Use and limitsUse it to question unnecessary work, not to assume every task can be safely compressed.

C. Northcote Parkinson, “Parkinson’s Law” (The Economist, 1955).

Wilson and Kelling proposed that visible disorder could affect informal social control and contribute to further disorder or crime.

Use and limitsThe causal claims and policing implications are contested; do not present this as a settled law or automatic policy prescription.

Broken Windows, Informal Social Control, and Crime: Assessing Causality in Empirical Studies (2020)

When search, distribution, and inventory costs fall, many low-demand offerings may collectively account for meaningful sales.

Use and limitsA large catalog does not guarantee profitability; demand concentration, costs, and discovery still matter.

Chris Anderson, “The Long Tail” (2004) and The Long Tail (2006).

In Christensen’s theory, disruption can begin in low-end or new-market footholds and move toward mainstream customers over time.

Use and limitsNot every breakthrough technology or successful entrant is disruptive in this specific sense.

Christensen Institute, Our Theories — Disruptive Innovation

A durable competitive advantage can protect a business’s returns from imitation or entry through mechanisms such as costs, switching barriers, or differentiated value.

Use and limitsIdentify evidence that the advantage persists; brand recognition or current profitability alone is insufficient.

Warren Buffett, Berkshire Hathaway shareholder letters.

Collins uses a flywheel metaphor for a reinforcing sequence in which consistent actions build momentum over time.

Use and limitsMap the actual reinforcing links; repeating an ineffective action does not create momentum automatically.

Jim Collins, The Flywheel Effect — author’s explanation

When different monies must circulate at a fixed official exchange value, people may spend the overvalued money and retain or export the undervalued money.

Use and limitsThe exchange-rate or legal conditions matter; this is not a universal law that low quality always drives out high quality.

Taleb’s concept concerns events that lie outside an observer’s expectations, have major consequences, and attract retrospective explanations that make them seem predictable.

Use and limitsThe classification depends on the observer’s knowledge; not every rare or damaging event is a black swan.

Nassim Nicholas Taleb, The Black Swan (2007).

Dialectical approaches examine tensions, opposing positions, and changes in concepts or social relations. Their meanings differ across philosophical traditions.

Use and limitsDo not reduce every tradition to a mechanical “thesis–antithesis–synthesis” formula.

G. W. F. Hegel, Phenomenology of Spirit (1807).

Deduction concerns conclusions that follow necessarily from premises when the argument is valid. Induction extends beyond observed cases and yields defeasible conclusions.

Use and limitsValid reasoning does not make false premises true; repeated observations do not logically prove every future case.

David Hume, A Treatise of Human Nature

Popper proposed that scientific claims should expose themselves to possible refutation by making claims that could conflict with observations.

Use and limitsA failed test also raises questions about measurement and auxiliary assumptions; one anomaly is not always decisive.

Karl Popper, The Logic of Scientific Discovery (English edition, 1959).

A thought experiment explores a carefully specified hypothetical situation to test concepts, implications, or the consistency of a theory.

Use and limitsIts conclusions depend on the setup; an imaginable scenario does not establish an empirical fact.

Galileo Galilei, Two New Sciences (1638).

A conclusion about what ought to be done does not follow from purely descriptive premises without some normative premise.

Use and limitsState the values linking evidence to a recommendation rather than presenting a value judgment as a fact.

David Hume, A Treatise of Human Nature

If an object’s parts are gradually replaced, what makes it the same object? The puzzle separates material continuity from continuity of form, function, or history.

Use and limitsIt is a philosophical puzzle with competing answers, not a rule that fixes personal or organizational identity.

Plutarch, Life of Theseus, section 23.

Plato’s allegory contrasts familiar appearances with a difficult process of education and reconsideration of what one takes to be real.

Use and limitsIt invites examination of knowledge and education; it does not prove that anyone who disagrees is deluded.

Plato, Republic, Book VII.

Teleological explanations refer to ends or functions; mechanistic explanations describe components and processes that produce an outcome.

Use and limitsA biological function does not imply conscious intention. Specify which kind of explanation a question requires.

Aristotle, Physics, Book II.

A category mistake treats something as belonging to a logical type to which it does not belong, producing a misleading question or claim.

Use and limitsClarify what kind of thing is being discussed before arguing about its properties.

Gilbert Ryle, The Concept of Mind (1949).

Abduction proposes a plausible explanation for observations. It generates hypotheses that can then be compared and tested.

Use and limitsThe best current explanation is not certain; alternatives and new evidence may change the assessment.

Charles S. Peirce, Harvard Lectures on Pragmatism (1903).