Affordance(n.) what an object or environment invites or permits
Originally coined by psychologist James Gibson to describe the action possibilities latent in an environment — a chair affords sitting, a knob affords turning, a ledge affords stepping on. Don Norman extended the concept to design: a well-designed object communicates its affordances clearly; a poorly designed one obscures them.
The concept has become essential in technology design. A button that looks pressable and is pressable has a correct affordance. A button that looks flat but is actually interactive has a false affordance — it violates user expectations and creates confusion.
Importantly, affordances are relational: they depend on both the properties of the object and the capabilities of the user. A large door handle affords pulling for most adults; it may not afford the same for a small child. The same environment offers different affordances to people with different bodies, knowledge, or intentions.
B
Bricolage(n.) creative construction from whatever materials happen to be available
From the French bricoler (to tinker). Claude Lévi-Strauss used the term in The Savage Mind to describe a mode of thought that works with the materials at hand rather than requiring purpose-built tools. The bricoleur solves problems by rearranging and repurposing what exists; the engineer solves problems by designing precisely the right tool for the task.
Neither mode is superior. Engineering produces optimal solutions when you have time, resources, and a well-defined problem. Bricolage produces working solutions quickly in conditions of constraint and ambiguity.
In practice, the most effective problem-solvers move between both modes. They bricolage when speed matters and resources are limited; they engineer when precision matters and the problem is well-understood. Treating bricolage as a lesser mode — mere improvisation, not real design — misses the cognitive sophistication it requires: a deep knowledge of available materials, a flexible sense of what counts as a solution, and the creativity to see uses that weren't designed in.
E
Episteme(n.) the foundational knowledge structure of a historical era
A term associated with Michel Foucault, who used it to describe the implicit structure of knowledge that makes certain ideas thinkable in a given historical period. The episteme is not a set of beliefs but the conditions under which beliefs can be formed, evaluated, and contested. Change the episteme and you change what counts as knowledge at all.
The concept is useful for historical analysis: it explains why ideas that seem obvious in retrospect were genuinely inconceivable in earlier periods — not because people were less intelligent, but because the conceptual infrastructure wasn't in place. Darwin's theory of natural selection required not just observations about species variation but also geology (deep time), political economy (Malthusian competition), and a cultural context willing to entertain gradual materialist explanations.
In everyday use: to change someone's episteme is to change the framework through which they interpret all evidence, not just to add one new fact.
Exaptation(n.) using an existing structure for a purpose it was not originally designed for
A term from evolutionary biology, coined by Gould and Vrba in 1982. Exaptation describes traits that evolved for one function but were later co-opted for another. Feathers likely evolved for thermoregulation before they were used for flight; the bones of the jaw became the bones of the inner ear. The structure arrived by one evolutionary path; the function it now serves was not what selected for it.
The concept extends productively into technology, culture, and cognition. Writing was invented for inventory accounting; it became literature, law, philosophy, and science. The internet was designed for military communication resilience; it became the infrastructure of global commerce, culture, and discourse. Smartphones were designed as communication devices; they became platforms for nearly every form of human activity.
Exaptation is important for understanding innovation: the most transformative technologies are often not purpose-built inventions but repurposings of existing structures into contexts their designers didn't foresee.
H
Heuristic(n.) a practical rule of thumb for decision-making under uncertainty
A heuristic is a mental shortcut that produces good-enough decisions without requiring exhaustive analysis. Unlike algorithms, heuristics do not guarantee an optimal result — they trade accuracy for speed. The tradeoff is often worth it: in most real decisions, gathering all the information needed for an optimal choice is prohibitively expensive, and a reasonable heuristic applied quickly outperforms a perfect answer arrived at too late.
Heuristics are not irrational. They are compressed experience. A skilled practitioner's intuitions are largely collections of domain-specific heuristics, accumulated over years of feedback. Novices lack these heuristics and must reason more explicitly. This is one reason why expertise feels like intuition: the heuristics have become automatic.
The danger of heuristics is their context-dependence. A rule that works well in one domain can misfire in another. The heuristic "move fast and iterate" produces good results in software development; it produces disasters in infrastructure engineering. Knowing when your heuristic applies is itself a higher-order skill.
M
Metacognition(n.) thinking about one's own thinking
Metacognition is the capacity to monitor, evaluate, and regulate your own cognitive processes. It includes knowing what you know and don't know (metacognitive knowledge), tracking your comprehension in real time (metacognitive monitoring), and adjusting your strategies when they aren't working (metacognitive control).
Research consistently shows that metacognitive skill is one of the strongest predictors of academic and professional performance — stronger, in many studies, than raw intelligence. This makes sense: a person who knows when they don't understand something and knows how to address that gap will outperform a smarter person who lacks this self-awareness.
Metacognition is teachable. Asking students to predict their own test performance, then comparing predictions to results, builds calibration. Requiring written explanations of problem-solving steps builds monitoring. Discussing when a given strategy is and isn't appropriate builds control. These are not soft skills. They are cognitive infrastructure.
P
Praxis(n.) knowledge made actionable through embodied practice
Drawn from Aristotle and later developed by Marxist and critical theory traditions, praxis names the integration of theory and practice — not theory applied to practice, but theory and practice fused in action. Praxis is distinguished from both theoria (pure contemplation) and poiesis (making things according to a plan). It describes action that is itself the site of understanding.
In practical terms: you do not fully understand a concept until you have applied it in conditions of genuine uncertainty. Reading about negotiation is theoria. Practicing scripted negotiation is poiesis. Negotiating a real deal where the outcome matters and adapting in real time is praxis.
The concept is useful as a corrective to purely theoretical education, which can produce graduates who can describe a skill without being able to perform it, and to purely practical training, which can produce competent technicians who cannot explain or adapt what they do.
T
Threshold Concept(n.) a concept that transforms your understanding once you grasp it
Introduced by Meyer and Land in 2003, a threshold concept is a concept within a discipline that, once understood, opens up a new way of thinking. It is "troublesome" (counterintuitive or initially uncomfortable), "transformative" (it changes how you see everything connected to it), and "irreversible" (once you get it, you can't un-get it).
Classic examples: the concept of opportunity cost in economics (every choice involves the cost of the next-best alternative); natural selection in biology (adaptation without intention or design); the derivative in calculus (instantaneous rate of change as the limit of average change).
The pedagogical implication is that curriculum design should identify threshold concepts and invest heavily in helping students cross them, rather than moving quickly through large amounts of surface material. Most disciplinary expertise is downstream of a small number of these transformative crossings. Finding them in a domain you are learning — and spending time at each one — is one of the highest-leverage activities in deliberate study.
Affordance (n.) what an object or environment invites or permits
Originally coined by psychologist James Gibson to describe the action possibilities latent in an environment — a chair affords sitting, a knob affords turning, a ledge affords stepping on. Don Norman extended the concept to design: a well-designed object communicates its affordances clearly; a poorly designed one obscures them.
The concept has become essential in technology design. A button that looks pressable and is pressable has a correct affordance. A button that looks flat but is actually interactive has a false affordance — it violates user expectations and creates confusion.
Importantly, affordances are relational: they depend on both the properties of the object and the capabilities of the user. A large door handle affords pulling for most adults; it may not afford the same for a small child. The same environment offers different affordances to people with different bodies, knowledge, or intentions.
Bricolage (n.) creative construction from whatever materials happen to be available
From the French bricoler (to tinker). Claude Lévi-Strauss used the term in The Savage Mind to describe a mode of thought that works with the materials at hand rather than requiring purpose-built tools. The bricoleur solves problems by rearranging and repurposing what exists; the engineer solves problems by designing precisely the right tool for the task.
Neither mode is superior. Engineering produces optimal solutions when you have time, resources, and a well-defined problem. Bricolage produces working solutions quickly in conditions of constraint and ambiguity.
In practice, the most effective problem-solvers move between both modes. They bricolage when speed matters and resources are limited; they engineer when precision matters and the problem is well-understood. Treating bricolage as a lesser mode — mere improvisation, not real design — misses the cognitive sophistication it requires: a deep knowledge of available materials, a flexible sense of what counts as a solution, and the creativity to see uses that weren't designed in.
Episteme (n.) the foundational knowledge structure of a historical era
A term associated with Michel Foucault, who used it to describe the implicit structure of knowledge that makes certain ideas thinkable in a given historical period. The episteme is not a set of beliefs but the conditions under which beliefs can be formed, evaluated, and contested. Change the episteme and you change what counts as knowledge at all.
The concept is useful for historical analysis: it explains why ideas that seem obvious in retrospect were genuinely inconceivable in earlier periods — not because people were less intelligent, but because the conceptual infrastructure wasn't in place. Darwin's theory of natural selection required not just observations about species variation but also geology (deep time), political economy (Malthusian competition), and a cultural context willing to entertain gradual materialist explanations.
In everyday use: to change someone's episteme is to change the framework through which they interpret all evidence, not just to add one new fact.
Exaptation (n.) using an existing structure for a purpose it was not originally designed for
A term from evolutionary biology, coined by Gould and Vrba in 1982. Exaptation describes traits that evolved for one function but were later co-opted for another. Feathers likely evolved for thermoregulation before they were used for flight; the bones of the jaw became the bones of the inner ear. The structure arrived by one evolutionary path; the function it now serves was not what selected for it.
The concept extends productively into technology, culture, and cognition. Writing was invented for inventory accounting; it became literature, law, philosophy, and science. The internet was designed for military communication resilience; it became the infrastructure of global commerce, culture, and discourse. Smartphones were designed as communication devices; they became platforms for nearly every form of human activity.
Exaptation is important for understanding innovation: the most transformative technologies are often not purpose-built inventions but repurposings of existing structures into contexts their designers didn't foresee.
Heuristic (n.) a practical rule of thumb for decision-making under uncertainty
A heuristic is a mental shortcut that produces good-enough decisions without requiring exhaustive analysis. Unlike algorithms, heuristics do not guarantee an optimal result — they trade accuracy for speed. The tradeoff is often worth it: in most real decisions, gathering all the information needed for an optimal choice is prohibitively expensive, and a reasonable heuristic applied quickly outperforms a perfect answer arrived at too late.
Heuristics are not irrational. They are compressed experience. A skilled practitioner's intuitions are largely collections of domain-specific heuristics, accumulated over years of feedback. Novices lack these heuristics and must reason more explicitly. This is one reason why expertise feels like intuition: the heuristics have become automatic.
The danger of heuristics is their context-dependence. A rule that works well in one domain can misfire in another. The heuristic "move fast and iterate" produces good results in software development; it produces disasters in infrastructure engineering. Knowing when your heuristic applies is itself a higher-order skill.
Metacognition (n.) thinking about one's own thinking
Metacognition is the capacity to monitor, evaluate, and regulate your own cognitive processes. It includes knowing what you know and don't know (metacognitive knowledge), tracking your comprehension in real time (metacognitive monitoring), and adjusting your strategies when they aren't working (metacognitive control).
Research consistently shows that metacognitive skill is one of the strongest predictors of academic and professional performance — stronger, in many studies, than raw intelligence. This makes sense: a person who knows when they don't understand something and knows how to address that gap will outperform a smarter person who lacks this self-awareness.
Metacognition is teachable. Asking students to predict their own test performance, then comparing predictions to results, builds calibration. Requiring written explanations of problem-solving steps builds monitoring. Discussing when a given strategy is and isn't appropriate builds control. These are not soft skills. They are cognitive infrastructure.
Praxis (n.) knowledge made actionable through embodied practice
Drawn from Aristotle and later developed by Marxist and critical theory traditions, praxis names the integration of theory and practice — not theory applied to practice, but theory and practice fused in action. Praxis is distinguished from both theoria (pure contemplation) and poiesis (making things according to a plan). It describes action that is itself the site of understanding.
In practical terms: you do not fully understand a concept until you have applied it in conditions of genuine uncertainty. Reading about negotiation is theoria. Practicing scripted negotiation is poiesis. Negotiating a real deal where the outcome matters and adapting in real time is praxis.
The concept is useful as a corrective to purely theoretical education, which can produce graduates who can describe a skill without being able to perform it, and to purely practical training, which can produce competent technicians who cannot explain or adapt what they do.
Threshold Concept (n.) a concept that transforms your understanding once you grasp it
Introduced by Meyer and Land in 2003, a threshold concept is a concept within a discipline that, once understood, opens up a new way of thinking. It is "troublesome" (counterintuitive or initially uncomfortable), "transformative" (it changes how you see everything connected to it), and "irreversible" (once you get it, you can't un-get it).
Classic examples: the concept of opportunity cost in economics (every choice involves the cost of the next-best alternative); natural selection in biology (adaptation without intention or design); the derivative in calculus (instantaneous rate of change as the limit of average change).
The pedagogical implication is that curriculum design should identify threshold concepts and invest heavily in helping students cross them, rather than moving quickly through large amounts of surface material. Most disciplinary expertise is downstream of a small number of these transformative crossings. Finding them in a domain you are learning — and spending time at each one — is one of the highest-leverage activities in deliberate study.