Ideas

Colour is the idea's field.

• A/r/tography A way of doing research where making art, teaching and studying are treated as one activity. The name joins artist, researcher and teacher (a/r/t) with 'graphy', meaning writing. A teacher who paints, keeps a journal about it and uses both to understand their classroom would be doing a/r/tography. It was developed by education scholars, led by Rita Irwin at the University of British Columbia, in the early 2000s.
• Aesthetics The study of beauty, taste and how things look, sound and feel to us. It asks why a sunset moves us, why one song seems better than another, or whether ugly things can still be good art. The German philosopher Alexander Baumgarten gave the field its name in the 1730s, from a Greek word meaning 'perception by the senses'.
• Anthropic principle The idea that the universe must allow for life like ours, because otherwise nobody would be here to notice it. It is like a fish wondering why its pond has exactly the right amount of water: a pond without water would have no fish asking. The physicist Brandon Carter named it in 1973 to explain why the laws of nature seem finely tuned for life.
• Architecture The art and practice of designing buildings and other spaces people use. An architect decides not only how a building stands up, but how it feels to move through it: where light falls, how big a room seems, how a doorway greets you. A school, a bridge and a subway station are all architecture, and people have practised it for thousands of years.
• Artificial intelligence (AI) Computer systems that do tasks we normally think need a human mind, such as understanding speech, recognizing faces, translating languages or playing chess. A phone that suggests the next word as you type is a small everyday example. The term was coined by the American computer scientist John McCarthy for a 1956 meeting at Dartmouth College, where the field was launched.
• Assemblage A kind of three-dimensional artwork made by putting together found objects, such as scrap wood, bottle caps, old toys or car parts. It is like collage, but instead of gluing flat pictures onto paper, you combine real things that stick out into space. The word came into use in the 1950s, though artists had been building works this way since the early twentieth century.
• Atemporality The feeling that time no longer runs in a clear line, because the past, present and future are all mixed together at once. On the internet, a song from 1965, a new video and a fake vintage photo sit side by side, and it is hard to say what era we are in. The American science fiction writer Bruce Sterling popularized the term in a 2010 talk.
• Authority The accepted right to make decisions and give orders that others follow. It differs from raw power: a bully can force you, but a referee has authority because players agree the role is legitimate. The German sociologist Max Weber, writing in the early 1900s, said authority comes from three sources: tradition (like a monarch), personal charisma (like a prophet), or rules and laws (like an elected official).
• Awesome immersion The experience of being completely absorbed in something so large, intense or beautiful that it fills you with awe. Standing inside a huge cathedral, under a night sky full of stars or in a room wrapped in projected images can make you forget yourself for a moment. It joins two ideas: immersion, being surrounded by an experience, and awe, the mix of wonder and smallness we feel before something vast.
• Black The darkest colour, which we see when little or no light reaches our eyes. A black shirt looks black because it absorbs nearly all the light that hits it instead of bouncing it back. People have used black pigments, like charcoal and soot, since the earliest cave paintings, and across cultures it has stood for night, mourning, elegance, power or rebellion.
• Body The physical form of a person: bones, muscles, organs, skin and senses working together. Beyond biology, thinkers ask how much our body shapes who we are, since we know the world by touching, moving and feeling. Catching a ball without thinking about it shows how the body 'knows' things the mind does not spell out. Societies also judge bodies differently by age, gender, race and ability.
• Capitalism An economic system where businesses and property are mostly owned by private people, not the government, and are run to make a profit. Prices are set largely by buyers and sellers in markets, like a lemonade stand charging more when it is hot out. The Scottish thinker Adam Smith described how markets work in 1776, and Karl Marx later wrote a famous critique of the system.
• Care (Sorge) The German word for "care" or "concern", used by the philosopher Martin Heidegger in his 1927 book Being and Time. For him, care is the basic shape of human life: we are always already caught up in things that matter to us, worrying about plans, people and our future. Even boredom or ignoring something is a way of caring. We never just exist neutrally, like a stone.
• Chance Using randomness on purpose to make decisions in art, music or writing. Instead of choosing every detail, a maker might roll dice, flip coins or drop paper to decide what comes next, the way a shuffled playlist makes surprising pairings. The technical name is aleatoricism, from the Latin word for dice. Composers and writers explored it widely in the mid-twentieth century to get past their own habits and taste.
• Chaos theory The science of systems that follow strict rules but still become unpredictable, because tiny changes at the start grow into huge differences later. Weather is the classic example: a small shift in wind today can change whether it storms next week. The American meteorologist Edward Lorenz found this in the 1960s and called it the 'butterfly effect', asking whether a butterfly's wings could set off a distant tornado.
• Cinema The art of telling stories and creating experiences with moving pictures, usually shown on a big screen. A film is really a fast series of still images; shown about 24 per second, our eyes see smooth motion, like a flip book. The first public paid film screenings took place in Paris in 1895, and cinema grew into one of the most popular art forms of the twentieth century.
• Clone A living thing that is a genetic copy of another, with the exact same DNA, the chemical instructions that build a body. Identical twins are natural clones of each other, and a plant grown from a cutting is a clone of its parent. In 1996, Scottish scientists made Dolly the sheep, the first mammal cloned from an adult cell, which raised hard questions about copying life.
• Collage An artwork made by cutting out and gluing together bits of paper, photos, fabric or other flat materials onto a surface. Pasting magazine pictures and ticket stubs into a scrapbook is a simple kind of collage. The name comes from the French word coller, 'to glue'. It became a serious art form in Paris around 1912, when painters began sticking newspaper and wallpaper into their pictures.
• Commodity A commodity is anything made to be bought and sold. The German thinker Karl Marx, in Capital (1867), described 'commodity fetishism': we start treating products as if their value lived inside them, forgetting the people and work that made them. When we see a pair of sneakers as simply 'worth $150', we lose sight of the factory workers, materials and labour behind that price.
• Communications The ways people share information and meaning with each other, from talking and writing to phones, television and the internet. Every message has a sender, a receiver and something carrying it between them, like a voice through air or a text through a network. The field of communications studies how messages travel, how they get changed or misunderstood, and how media shape the way we think.
• Consciousness The fact of being aware: having experiences, feelings and thoughts from the inside. When you taste chocolate, there is 'something it is like' to be you tasting it, and that inner experience is consciousness. Scientists can study which parts of the brain are active, but the philosopher David Chalmers called it the 'hard problem' in 1995: explaining why physical brain activity feels like anything at all.
• Consumption Consumption means using up goods and services, and consumerism is a way of life built around buying more and more of them. It is the belief, often encouraged by advertising, that shopping will make us happier or show who we are, like feeling you need the newest phone when your old one still works. Critics link it to waste, debt and environmental harm; supporters say spending drives the economy.
• Context The surrounding situation that gives something its meaning. The same words, 'Nice job', can be praise or sarcasm depending on who says them, when and how. A photograph, a painting or a sentence can mean very different things depending on where it is shown, when it was made and who is looking. Understanding context means looking beyond the thing itself to everything around it.
• Crime fiction Stories about crimes and the people who commit, suffer or solve them, most often a murder and the detective who figures out whodunit. Readers enjoy following the clues and trying to beat the detective to the answer, like a puzzle in story form. The modern detective story began in the 1840s, and the genre now includes police dramas, thrillers, true-crime-style novels and courtroom stories.
• Critical theory A way of studying society that aims not only to explain it but to change it, by exposing hidden forms of power and unfairness. For example, it might ask who benefits when a TV show makes only one kind of family seem normal. It began in the 1930s with a group of German thinkers called the Frankfurt School, and the name now also covers many later approaches that question power.
• Cultural studies A field that studies everyday culture, like TV, music, fashion, sports, slang and shopping, and how it connects to power, class, race and identity. It takes a pop song or a video game as seriously as a classic novel, asking what it says about the people who make and enjoy it. It began at the University of Birmingham in England in 1964, with scholars such as Stuart Hall.
• Culture The shared ways of life of a group of people: their language, beliefs, customs, food, art, music and habits. Culture is learned, not inherited in our genes, which is why a child raised in Montréal and one raised in Tokyo grow up with different holidays, jokes and table manners. Every group, from a nation to a school or a gaming community, has its own culture.
• Cyberbalkanization The splitting of the internet into separate groups that rarely talk to each other, like a region breaking into small rival states (the Balkans are the example behind the name). It happens when people only follow sources they already agree with, or when countries block parts of the web. The MIT researchers Marshall Van Alstyne and Erik Brynjolfsson used the term in 1996; a related word is 'splinternet'.
• Cyberspace The imagined 'space' where online activity happens: websites, chats, games and data, which feel like a place even though they exist in computers and networks. When you say you 'went to' a website or 'met' someone in a game, you are treating cyberspace as a place. The science fiction writer William Gibson coined the word in 1982 and made it famous in his 1984 novel Neuromancer.
• Cyborg A being that is part living organism and part machine, short for 'cybernetic organism'. A person with a pacemaker or a cochlear implant, a device that helps the deaf hear, is already a small step toward a cyborg. The scientists Manfred Clynes and Nathan Kline coined the word in 1960, and in 1985 the American thinker Donna Haraway used it to question fixed lines between human, animal and machine.
• Dada An art movement that mocked logic, good taste and tradition with nonsense, jokes and shock. Its makers wrote poems from random words pulled from a hat and put ordinary objects on display as art. It began in Zurich, Switzerland, in 1916 during the First World War, as a protest against a society that had produced such a senseless war. Even its name is a nonsense word.
• Dasein A German word meaning 'being there', used by the philosopher Martin Heidegger for the kind of being that humans have. His point is that we are not just objects among objects; we are beings who care about our own existence and always find ourselves already in a world of tasks, tools and other people. He set out the idea in Being and Time (1927).
• Decentring Moving something away from the middle, where it was assumed to belong, to show that it is not the natural centre of everything. Just as astronomers once learned that Earth is not the centre of the universe, twentieth-century thinkers argued that the individual self, or one culture's point of view, is not the fixed centre of meaning. The French philosopher Jacques Derrida pushed this idea in a 1966 lecture.
• Desire The feeling of wanting something, from a snack to success to another person. Philosophers have long asked whether desire leads us to happiness or keeps us restless, since getting what we want often just makes us want something new, like finishing one phone game and immediately wanting the next. The French psychoanalyst Jacques Lacan argued that desire grows from a sense of lack that can never be fully filled.
• Difference (différance) A word invented by the French philosopher Jacques Derrida in the 1960s. It mixes two French meanings: to differ and to defer, or put off. Words get their meaning only by differing from other words, like 'cat' from 'hat' or 'car', and a final meaning is always put off, since each word leads to more words, like a dictionary that only sends you to other entries.
• Digital art Art made or shown using computers and digital technology, where images, sounds and movement are stored as numbers. It includes things like digital painting on a tablet, animations, video games, computer-generated images, websites and interactive installations that respond to viewers. Because a digital file can be copied perfectly, it raises new questions about what counts as the original. Artists began using computers to make images in the 1960s.
• Discontinuity The idea that knowledge does not always grow smoothly, but sometimes jumps. A new way of seeing breaks so completely with the old one that the two can hardly talk to each other, like the switch from believing the sun circles the earth to knowing the earth circles the sun. The French philosopher Gaston Bachelard called this an "epistemological rupture" (a break in knowing) in 1938.
• Discourse At its simplest, discourse means talk or writing on a subject. Thinkers also use it for the shared rules of a field that decide what can be said, who gets to say it and what counts as true, like the way doctors talk about illness. The French thinker Michel Foucault showed in the 1960s and 1970s how these ways of speaking shape what people believe.
• Earnestness (New Sincerity) A turn back toward meaning what you say after years of jokey, knowing irony. Instead of hiding behind sarcasm, people risk being openly sincere, even if it looks uncool, like a song that simply says "I love you" without a wink. The American writer David Foster Wallace argued for it in a 1993 essay, and the label "New Sincerity" spread in the 1990s and 2000s.
• Ecological perspective A way of understanding a person by looking at everything around them, not just the person alone. Picture a child at the centre of rings: family and school closest, then neighbourhood and parents' jobs, then the wider culture and the times they live in. Each ring shapes the child. The American psychologist Urie Bronfenbrenner set out this model in 1979.
• Edmund Husserl Edmund Husserl (1859–1938) was an Austrian-born German philosopher who founded phenomenology, the study of experience exactly as it shows up to us. Instead of asking what a cup is "really" made of, he asked how it appears: its colour, its hidden back side we assume is there. He urged setting aside assumptions to describe experience carefully, calling this a return "to the things themselves".
• Ethics The study of how we ought to act: what is right and wrong, good and bad, and why. It asks questions like whether lying is ever acceptable, or what we owe to strangers, animals or future generations. Philosophers have argued about it since ancient Greece, judging actions by their results, by rules and duties, or by the kind of person they make you.
• Ethnicity A sense of belonging to a group that shares a culture, such as a language, religion, food, customs or a story about where its ancestors came from. Unlike race, which is usually about physical appearance, ethnicity is about shared ways of life. A person might be Canadian by citizenship and Punjabi or Ukrainian by ethnicity, and ethnic identity can change over time.
• Evasive manoeuvres Moves made to dodge being caught or pinned down, like a pilot swerving to avoid a missile. As an idea, it means refusing to stay in one fixed position that others can easily label, judge or control. Instead of meeting a rule head-on, you slip around it, change direction or keep several options open so no single description sticks.
• Existentialism The idea that life has no meaning handed to us in advance, so each person has to make their own through the choices they make. We are free, and responsible for that freedom, which can feel dizzying. The French philosopher Jean-Paul Sartre summed it up in 1945 as "existence precedes essence": you exist first, then decide who you are.
• Expanded painting Painting that spills beyond the flat rectangle on the wall. Colour and brushwork might spread across floors, rooms, fabric, found objects or light, so that painting becomes something you walk into rather than look at. The phrase echoes the American critic Rosalind Krauss, who wrote in 1979 about sculpture in an "expanded field", and came into use for painting from the 1990s onward.
• Fashion The styles of clothing, hair and appearance that are popular at a given time, and the way they keep changing. Fashion is also a language: what you wear signals your age, group, class or mood before you say a word, like a school uniform versus a band T-shirt. It is also a huge industry that designs, makes and sells those styles each season.
• Feminism The belief that women and men should have equal rights and opportunities, and the movements that work toward that. It has pushed for the vote, equal pay and control over one's own body. In the arts, a feminist movement in the 1960s and 1970s asked why so few women appeared in museums and history books, as the historian Linda Nochlin did in a 1971 essay.
• Ferdinand de Saussure Ferdinand de Saussure (1857–1913) was a Swiss linguist who helped found modern linguistics. He showed that words are signs made of two parts: a sound or written form, and the idea it calls up. The link between them is arbitrary; nothing about the sound "tree" is tree-like. Words get meaning from how they differ from other words. His ideas launched structuralism and semiotics, the study of signs.
• Film studies The study of movies as an art form and as part of society. It looks at how films are made (camera angles, editing, sound), what they mean, and what they say about the times that produced them, the way English class studies novels. It became a university subject in the 1960s and 1970s, drawing on older film criticism from France and elsewhere.
• Flesh An idea from the French philosopher Maurice Merleau-Ponty, in a book published after his death in 1964. He noticed that when your right hand touches your left, each hand both touches and is touched. Flesh names this shared stuff: we are not minds looking at the world from outside, but bodies made of the same world we see and feel.
• Fragment A broken-off piece of something larger, or a piece of writing or art that is left deliberately incomplete. Think of an ancient statue missing its arms, which can feel more suggestive than a whole one, because your imagination fills in the rest. German Romantic writers such as Friedrich Schlegel, around 1798, made the short, unfinished fragment a form of its own.
• Friedrich Nietzsche A German philosopher (1844–1900) who first trained in philology, the study of old languages and texts. He is famous for saying 'God is dead', meaning that belief in God no longer held modern society's values together. He urged people to question inherited morals and create their own values, and imagined the 'Übermensch', or 'overhuman', as someone who could do this.
• Félix Guattari Félix Guattari (1930–1992) was a French psychoanalyst, philosopher and activist who worked at an experimental psychiatric clinic, La Borde. With the philosopher Gilles Deleuze he wrote Anti-Oedipus (1972) and A Thousand Plateaus (1980), which pictured desire as a creative force and knowledge as a rhizome, a root network with no centre. In The Three Ecologies (1989) he linked care for nature, society and the mind.
• G. W. F. Hegel G. W. F. Hegel (1770–1831) was a German philosopher. His best-known idea is the dialectic: thinking moves forward through conflict, as one idea meets its opposite and both are taken up into a fuller understanding, much like an argument that ends with both sides learning something. He saw all of history as this kind of growth toward freedom, set out in Phenomenology of Spirit (1807).
• Genre A category of art, writing, music or film whose works share familiar features. Horror, romance, westerns and hip hop are genres: once you know one, you can expect certain settings, characters or sounds, like a haunted house or a car chase. Genres help audiences choose and creators play with expectations, and they keep changing and mixing over time.
• Gilles Deleuze Gilles Deleuze (1925–1995) was a French philosopher who wanted to think about the world in terms of change and difference, rather than fixed things and identities. In Difference and Repetition (1968) he argued that even repeating something always makes a difference. With the psychoanalyst Félix Guattari he wrote A Thousand Plateaus (1980), which introduced the rhizome: a network with no centre, like grass roots, where anything can connect to anything.
• Globalization The way the world's countries have become more tightly connected through trade, travel, communication and culture. A phone designed in one country, built from parts made in several others and sold everywhere is a typical example, as is watching the same shows worldwide. It sped up from the late 20th century with cheaper shipping and the internet, bringing both benefits and inequalities.
• Grand narratives Big stories that claim to explain all of history or knowledge, such as "science will steadily lead humanity to progress" or "history is heading toward a workers' revolution". The French philosopher Jean-François Lyotard argued in 1979 that people no longer trust such all-explaining stories, and instead live by many smaller, local ones. He called this distrust the postmodern condition.
• Hegemony Leadership or control that works mostly through agreement rather than force. A ruling group stays on top because its values come to seem like plain common sense, so people accept them without being made to, like assuming success simply means earning more money. The Italian thinker Antonio Gramsci developed the idea of cultural hegemony in his prison notebooks around 1930.
• Hermeneutic circle The idea that you understand the parts of something through the whole, and the whole through its parts, going back and forth. When you read a sentence, each word makes sense from the sentence, yet the sentence is built from the words. Understanding grows as you circle. German thinkers developed it in the 1800s, and Heidegger and Hans-Georg Gadamer expanded it in the 1900s.
• History The study of the past, based on evidence such as documents, objects and memories, and also the story we tell about that past. Historians ask not just what happened but why, and whose view is being told: a war looks different from the winners' and the losers' side. The ancient Greek writer Herodotus, around 430 BCE, is often called the first historian.
• Holistic integration Seeing things as wholes rather than as separate pieces, because the whole can do what the parts cannot. A single musical note is only a sound, but notes together make a melody that exists in none of them alone. The South African statesman Jan Smuts coined the word "holism" in 1926, though the idea goes back to Aristotle.
• Humanism An outlook that puts human beings, their abilities and their well-being at the centre, rather than relying only on religion or tradition. It began in 14th- and 15th-century Italy, when scholars such as Petrarch revived ancient Greek and Roman writing and celebrated human potential. Today it often means living ethically using reason and compassion, without needing belief in a god.
• Hybridity The mixing of different cultures into something new that belongs fully to none of them. Think of Korean tacos, Spanglish, or a family that celebrates holidays from two traditions. Rather than a watered-down copy, the mix can be creative and challenge the idea of pure cultures. The theorist Homi K. Bhabha made the idea central to post-colonial thinking in 1994.
• Hyperreality A state where copies and images feel more real than the reality they came from, until we can no longer tell the difference. A theme park's spotless "Main Street" or a heavily filtered photo can seem better than the real thing. The French thinker Jean Baudrillard developed the idea in Simulacra and Simulation (1981), and the Italian writer Umberto Eco explored it too.
• Identity Who a person is, or feels they are, and how they are seen by others. It is built from many things at once: name, family, nationality, gender, religion, job, the music you love. Someone can be a daughter, a student, a goalie and a Montrealer all together. Social scientists study how identities form, shift over time and bring people together or apart.
• Ihab Hassan Ihab Hassan (1925–2015) was an Egyptian-born American literary theorist who helped bring the word "postmodernism" into wide use from the late 1960s. He described postmodern writing as playful, open-ended and uncertain, and in a well-known table he set its traits against modernism's, such as chance against design and play against purpose. He also wrote about silence in literature.
• Immanuel Kant A German philosopher (1724–1804) who spent his whole life in the town of Königsberg. He argued that the mind is not a blank screen: it arranges experience using built-in rules such as space, time and cause and effect, a bit like coloured glasses you can never take off. In ethics, he said to act only in ways you could want everyone to act.
• Inclusive Making sure everyone can take part, especially people who are often left out because of poverty, disability, race, gender or other reasons. An inclusive school, for example, has ramps as well as stairs and teaches in ways that suit different learners. The opposite, social exclusion, became a common term in France in the 1970s to describe people pushed to society's edges.
• Indeterminacy The idea that some things cannot be settled or pinned down to one exact answer. A sentence can carry several meanings at once, and no rule decides which is final. The American philosopher W. V. O. Quine argued in 1960 that even translation is never fully fixed: a word in an unknown language could fit several meanings equally well.
• Interdisciplinary imagination Combining ideas and methods from different fields to solve problems that no single field can handle alone. Climate change, for instance, needs scientists, economists, engineers and artists working together. Interdisciplinary thinking is the knack for seeing how a tool from biology might help in city planning, or how history can inform medicine. Universities began promoting it widely in the 20th century.
• Interpretation Working out what something means, whether a poem, a law, a dream or a friend's text message. The study of how we interpret is called hermeneutics, named after Hermes, the Greek messenger god. It began with explaining the Bible and legal texts, then grew in the 1800s and 1900s into a wider theory that all understanding involves interpreting.
• Intersubjectivity The shared understanding that forms between people's minds. Each of us sees the world from inside our own head, yet we can agree that a joke is funny or that a meeting is at noon, because meaning is built between us. The German philosopher Edmund Husserl developed the idea in the early 1900s, and psychologists use it to study how babies learn to share attention.
• Irony Saying or showing one thing while meaning something different, often the opposite. Calling a rainstorm "lovely weather" is verbal irony. Dramatic irony is when the audience knows something a character does not. Irony can be playful, sad or critical, and it depends on the listener catching the gap. The ancient Greek philosopher Socrates famously pretended ignorance to expose others' mistakes.
• Jacques Derrida Jacques Derrida (1930–2004) was a French philosopher, born in Algeria, best known for deconstruction. Deconstruction is a way of reading closely to show that a text's meaning is never fully fixed and often depends on the very things it tries to push aside. For example, 'day' only makes sense against 'night'. He set out these ideas in books like Of Grammatology (1967).
• Jacques Lacan A French psychoanalyst (1901–1981) who reread Sigmund Freud through the study of language. He argued that the unconscious, the part of the mind we are not aware of, is structured like a language. He is known for the 'mirror stage': a baby seeing itself in a mirror forms a sense of self from an outside image, so our identity is always partly borrowed.
• Jean Baudrillard Jean Baudrillard (1929–2007) was a French sociologist and philosopher who wrote about media, advertising and consumer society. His best-known idea is hyperreality: a world so full of copies and images that they feel more real than the real thing, like a theme-park 'Main Street' that seems more like a small town than an actual one. He set this out in Simulacra and Simulation (1981).
• Jean-Paul Sartre Jean-Paul Sartre (1905–1980) was a French philosopher, novelist and playwright, and the best-known voice of existentialism. His key idea is that "existence comes before essence": people are not born with a fixed purpose, so we create who we are through our choices. That freedom comes with full responsibility, which can feel heavy. He also wrote the play No Exit, famous for the line "Hell is other people."
• John Barth John Barth (1930–2024) was an American novelist and essayist known for playful fiction that talks about its own making, called metafiction. His 1967 essay 'The Literature of Exhaustion' argued that traditional forms of the novel felt used up, so writers should play with those forms knowingly. His story collection Lost in the Funhouse (1968) is a well-known example, and his later essays helped define postmodern fiction.
• Jouissance A French word meaning enjoyment, used by thinkers for a pleasure so intense it overflows, sometimes tipping into pain, like the rush of a scary ride. The psychoanalyst Jacques Lacan used it from the 1950s for excess beyond ordinary pleasure. The critic Roland Barthes, in 1973, contrasted comfortable reading pleasure with the jolting bliss of texts that unsettle you.
• Judith Butler Judith Butler (born 1956) is an American philosopher and gender theorist. In Gender Trouble (1990), they argued that gender is performative: not something we simply are, but something we keep doing through everyday acts like how we dress, speak and move. Just as repeating a habit makes it feel natural, repeating these acts makes gender seem fixed. Butler also writes about grief, violence and who counts as fully human.
• Karl Marx A German philosopher, economist and revolutionary (1818–1883) who lived much of his life in London. He argued that history is driven by struggles between classes, such as factory owners and workers. Under capitalism, he said, owners profit by paying workers less than the value their work creates. The Communist Manifesto (1848, with Friedrich Engels) and Capital shaped modern politics.
• Knowledge Knowing something, rather than just believing it or guessing. You can believe it will rain and be right by luck, but knowing seems to need good reasons too. Since Plato, philosophers have often defined knowledge as a belief that is true and justified. In 1963, Edmund Gettier described lucky cases that fit this definition yet still don't feel like knowing.
• Language A shared system of sounds, signs or gestures that people use to pass meaning to one another. A small set of words and rules can be combined to say things no one has ever said before, like building blocks with endless possible builds. There are about 7,000 languages in the world today, including sign languages, which are complete languages of their own.
• Logocentrism The habit, in Western thinking, of treating speech and direct presence as more real or trustworthy than writing or other signs. It is like believing a spoken promise holds the 'true' meaning, while a written one is just a copy. The word dates from the 1920s, but the French philosopher Jacques Derrida made it famous in 1967, arguing that meaning is never fully present in any form.
• Ludwig Wittgenstein Ludwig Wittgenstein (1889–1951) was an Austrian-British philosopher who worked mainly on language and logic. His early work argued that sentences picture facts, and that we should stay silent about what can't be said. Later he changed his mind: the meaning of a word is how people use it, in "language games" tied to daily life, just as the meaning of a chess piece depends on the game's rules.
• Marshall McLuhan A Canadian thinker (1911–1980) who studied how media, meaning the tools we use to communicate, change us. His famous line 'the medium is the message' means the form matters more than the content: television changed daily life more than any single show did. He also predicted a 'global village', a world tied together by electronic media, decades before the internet.
• Martin Heidegger Martin Heidegger (1889–1976) was a German philosopher whose Being and Time (1927) asked what it actually means for something to exist. He argued we are always already involved in the world, not detached observers: you notice a hammer only when it breaks, not while you use it. He also wrote about technology and our awareness of death. His support for the Nazis remains controversial.
• Maurice Merleau-Ponty A French philosopher (1908–1961) who argued that we understand the world first through our bodies, not through pure thinking. A typist's fingers know where the keys are before the mind could say. In Phenomenology of Perception (1945), phenomenology meaning the study of experience as it is lived, he showed that seeing, touching and moving are already a kind of knowing.
• Meaning What a word, sign or sentence stands for or communicates. 'Dog' means a certain kind of animal, while a red light means stop without using any words at all. Philosophers ask where meaning comes from: from the things words point to, from what the speaker intends, or, as Ludwig Wittgenstein suggested, from how people actually use words in daily life.
• Mediation The idea that we rarely meet the world directly; something always stands in between and shapes what reaches us. You learn about a faraway war through a news camera, an editor and a screen, and each one shapes the story. In Marxist thought, mediation also describes how things like money or the market connect people while shaping their relationships.
• Meditation A practice of training attention, often by sitting quietly and focusing on the breath, a word or a feeling. When the mind wanders, as it always does, you notice and gently bring it back, a bit like teaching a puppy to stay. It has ancient roots in Hindu, Buddhist and other traditions, and today is widely used to reduce stress.
• Meta-narrative A big story that claims to explain everything else, like the idea that history is steadily progressing toward freedom, or that science will eventually answer every question. Smaller stories get their meaning by fitting into it. In 1979, the French philosopher Jean-François Lyotard described our era as one of 'incredulity toward meta-narratives': people no longer trust any single grand story.
• Metacognition Thinking about your own thinking. It is what you do when you notice you don't understand a paragraph and go back to reread it, or realize you learn better by drawing diagrams. The psychologist John Flavell named it in the 1970s. Good metacognition helps people plan, check their work and know the limits of what they know.
• Metonymy A figure of speech where something is called by the name of a thing closely linked to it. When people say 'the Crown' for the monarchy, or 'Hollywood' for the American film industry, that is metonymy. It differs from metaphor, which links things by likeness; metonymy links them because they are connected or close together.
• Metropolis A very large city that is the main centre of a region or country, pulling in people, money and culture from all around. Toronto, Paris and Tokyo are examples. The word comes from Greek for 'mother city', once meaning a city that founded colonies. In 1903, the German sociologist Georg Simmel wrote about how big-city life makes people guarded and reserved.
• Michel Foucault Michel Foucault (1926–1984) was a French philosopher and historian of ideas. He studied how power works not just through kings and laws but through everyday institutions like prisons, hospitals and schools, which watch, sort and train people. In Discipline and Punish (1975) he argued that being constantly observed teaches us to police ourselves. He also showed that knowledge and power support each other.
• Mimesis The Greek word for imitation, used for the way art copies or represents the world. A painting of a bowl of fruit or a play about a family quarrel is mimesis. Plato distrusted it as a copy of a copy, far from the truth. His student Aristotle defended it, saying humans learn by imitating and enjoy seeing things well represented.
• Modernism A movement in art, writing, music and design, roughly from the 1890s to the 1950s, that broke with old traditions to capture modern life. Instead of painting a scene as it looks from one spot, a Cubist painter might show it from many sides at once. Driven by cities, machines and war, its spirit is often summed up by the slogan 'Make it new.'
• Moral courage The courage to do what you believe is right even when it might cost you friends, a job or your reputation. Physical courage faces danger to the body; moral courage faces disapproval or loss. Speaking up when a classmate is being mocked, or reporting wrongdoing at work, are everyday examples. It often means acting alone, before anyone else agrees.
• Morphological analysis A method for solving complicated problems by breaking them into their main parts and listing every option for each part. To design a new chair, you might list materials, numbers of legs and seat shapes, then mix and match to find combinations no one has tried. The Swiss astronomer Fritz Zwicky developed the method in the 1940s.
• Narrative A story: an account of connected events, usually with a beginning, middle and end, told from some point of view. It is not just what happened, but how it is told. The same hockey game becomes a different story when told by the winning side or the losing side. People also use narratives to make sense of their own lives.
• Nature The physical world and everything in it that humans did not make: plants, animals, weather, rivers and the laws that govern them. The word can also mean a thing's basic character, as in 'human nature'. Where nature ends and culture begins is often debated: is a planted garden or a farmed field natural? Many thinkers argue the line is blurry.
• Neurosis An older term for long-lasting mental distress, like anxiety, obsessions or phobias, in which a person still stays in touch with reality. Someone who checks the stove twenty times before leaving, knowing it is off, was once called neurotic. Sigmund Freud saw neuroses as coming from hidden inner conflicts. Doctors today mostly use more specific terms, such as anxiety disorder.
• New media Art and communication made with digital or electronic technology, such as computers, video, the internet, games and interactive installations. Unlike a painting that just hangs on a wall, a new media work might change when you move, click or speak near it. The term took hold in the 1990s, when home computers and the web made these tools widely available.
• Nihilism The view that life has no built-in meaning, purpose or value, and that nothing is truly right or wrong. It comes from the Latin nihil, 'nothing'. Imagine realizing that the rules of a game were simply made up: nihilism applies that feeling to all of morality. Friedrich Nietzsche warned it would spread as religious belief faded, and looked for ways past it.
• Origin / copy The question of what makes an original different from a copy, and whether the difference still matters. A handwritten letter feels special in a way a photocopy doesn't, but a digital file can be copied endlessly with no loss. The French thinker Jean Baudrillard used the word simulacrum for a copy with no original, like a theme-park 'Main Street' modelled on a town that never existed.
• Parody An imitation that exaggerates the style of something to make fun of it or comment on it. A spoof movie trailer that copies every action-film cliché, from slow-motion explosions to the deep-voiced narrator, is parody. It only works if the audience recognizes the original. It goes back to ancient Greece, and in Canada parody is protected as fair dealing under copyright law.
• Pattern Something that repeats in a regular, predictable way, whether in shapes, sounds, numbers or events. The stripes on a zebra, the beat of a song and the way traffic builds every weekday at 5 p.m. are all patterns. Spotting patterns helps us predict what comes next, which is why the human brain is so quick to find them, sometimes even seeing faces in clouds.
• Performance Art where the work is an action done live by a person, in front of an audience or a camera, rather than an object like a painting. The body, time and place become the materials. A piece might be someone sitting silently for hours, or a staged event on a busy street. It grew into its own form of art in the 1960s and 1970s.
• Philosophy The practice of asking basic questions and reasoning carefully about them: What is real? What can we know? How should we live? Unlike science, it often tackles questions experiments can't settle, such as whether it is ever right to lie. The word comes from Greek for 'love of wisdom', and it began in several places, including ancient Greece, India and China.
• Play Activity done for its own sake, freely and for enjoyment, rather than to reach a goal. Children playing house, a pickup game of hockey or doodling on a napkin are all play. It often has its own made-up rules and a separate 'pretend' space. The Dutch historian Johan Huizinga argued in 1938 that play is older than culture and helps shape it.
• Polycultural The idea that cultures have always mixed and borrowed from each other, so no culture is pure or separate. Pizza, reggae and the English language all grew out of many sources. It differs from multiculturalism, which pictures cultures as distinct groups living side by side. The historians Robin D. G. Kelley and Vijay Prashad argued for this view around 1999 to 2001.
• Post-colonialism The study of how colonialism, when powerful countries ruled other lands and peoples, still shapes the world after those empires ended. It looks at lasting effects on borders, languages, wealth and how people see themselves. Why do so many countries in Africa use English or French? That is one question it asks. Edward Said's book Orientalism (1978) was an early landmark.
• Post-digital A way of describing life after digital technology stopped being new and became ordinary, like electricity or plumbing. Nobody gets excited that a fridge has a computer chip; the digital is simply everywhere. The term also covers a renewed interest in the handmade and analogue, like vinyl records and film cameras. It came into use around 2000.
• Poststructuralism A movement in French philosophy from the late 1960s that argued meaning is never fixed or complete. Earlier structuralism said we could map the hidden rules behind language and culture, like a grammar. Poststructuralists replied that these structures shift, and depend on who is reading and when. Jacques Derrida, Michel Foucault and Roland Barthes are key names.
• Power The ability to make things happen or to get others to do what you want, even if they would rather not. A government passing a law, a boss setting schedules and a friend who always picks the movie all show power. The French philosopher Michel Foucault argued it is not just held by a few at the top; it runs through everyday rules and habits.
• Practice Doing something, as opposed to only thinking or talking about it. The Greek word praxis means action, and philosophers use it for turning ideas into real-world activity. Reading about swimming is theory; getting in the pool is practice. Karl Marx argued that the point of thinking is not just to understand the world but to change it.
• Production How a society makes the things it needs, and who owns and controls the means of making them. Karl Marx called this the mode of production. Under feudalism, peasants farmed land owned by lords; under capitalism, workers earn wages using factories and machines owned by others. Marx argued that the way things are produced shapes a society's laws, beliefs and politics.
• Psychic masochism An idea from psychoanalysis that some people unconsciously seek out defeat, rejection or suffering, and even get a hidden satisfaction from it. Think of someone who keeps landing in situations where they will be treated unfairly, then feels wronged all over again. The Austrian-American psychoanalyst Edmund Bergler made the idea central to his work in the 1940s and 1950s, calling such people 'injustice collectors'.
• Queer theory A way of studying gender and sexuality that questions the idea that they are natural, fixed categories. It asks why some identities, like being straight, are treated as 'normal' and others as different. Just as rules about who wears pink or blue are learned, it sees many ideas about gender as shaped by culture. It emerged in the early 1990s, with Judith Butler a key figure.
• Radical democracy The idea that democracy should go deeper than voting every few years, with ordinary people taking part in decisions and disagreement treated as healthy rather than a problem. Picture a neighbourhood assembly where people argue openly about how to spend the local budget. The political theorists Ernesto Laclau and Chantal Mouffe developed an influential version in their 1985 book Hegemony and Socialist Strategy.
• Rationality Thinking and acting according to good reasons: believing things that fit the evidence and choosing actions that serve your goals. If you want to pass a test, studying is rational; hoping for luck is not. As psychologists like Daniel Kahneman have shown, people are often less rational than they think, using mental shortcuts that lead to predictable mistakes.
• Realism An approach to art that shows ordinary life as it actually looks, without making it prettier or grander. Instead of gods and heroes, a realist painter might show farm workers, a crowded street or an unmade bed. The movement took off in France in the 1840s and 1850s, led by the painter Gustave Courbet, and the same idea shaped novels by writers like Gustave Flaubert.
• Reason Our ability to think things through step by step and reach conclusions we can back up. When you notice the ground is wet, rule out a sprinkler and decide it rained, you are using reason. Philosophers since ancient Greece have treated it as what sets humans apart, and in the 1700s the Enlightenment made reason, rather than tradition or religious authority, the main test of what to believe.
• Reference The link between a word, picture or sign and the actual thing it points to. The word "moon" and a drawing of a crescent both refer to the same object in the sky. Reference can also mean one work pointing to another, like a song quoting a famous line. Philosophers such as Gottlob Frege, around 1892, asked how words manage to hook onto the world at all.
• Relativism The idea that what counts as true or right depends on who you are and where you come from, not on one fixed standard. For example, table manners that are polite in one country can be rude in another. The idea goes back to the ancient Greek thinker Protagoras, who said "man is the measure of all things." Critics ask whether it applies to everything, including serious moral questions.
• Representation Using one thing to stand for another. A portrait represents a person, a map represents a city, and a stick figure on a door represents "washroom." A representation never copies its subject completely; it picks certain details and leaves others out, which shapes how we see the real thing. Thinkers since Plato and Aristotle have argued about how faithful, and how honest, representations can be.
• Resolution How much detail an image holds, usually measured in pixels, the tiny coloured squares a digital picture is made of. A photo 4000 pixels wide shows fine details like single hairs, while the same photo at 200 pixels wide looks blocky when enlarged. Screens, cameras and printers all have a resolution, and more pixels packed into each centimetre means a sharper picture.
• Responsive Compassion Compassion that notices someone else's suffering and actually responds to it, rather than just feeling sorry. Seeing a friend upset and sitting with them, listening, or helping them get what they need is responsive compassion. The word compassion comes from Latin for "suffering with." It is central to Buddhism, Christianity and many other traditions, and psychologists today study it as a skill that can be practised.
• Rhizome A way of picturing how things connect. Most knowledge is drawn like a tree: one trunk, with branches splitting off in order. A rhizome is like grass or ginger roots: no top, no centre, and any part can link to any other. The philosophers Gilles Deleuze and Félix Guattari used it in 1980 to describe things that grow sideways, like languages, cultures or the internet.
• Romanticism A movement in art, music and writing, roughly 1790 to 1850, that valued strong feeling, imagination and wild nature over cool reason and strict rules. Think of a lone figure on a cliff above stormy seas, or poems about a single flower stirring deep emotion. It grew partly as a reaction against the Enlightenment and factories, with figures like William Wordsworth, Caspar David Friedrich and Beethoven.
• Sam Harris Sam Harris (born 1967) is an American neuroscientist, philosopher and author. He became known with The End of Faith (2004), a sharp criticism of religion, and argued in The Moral Landscape (2010) that science can help answer questions of right and wrong by studying human well-being. He also argues that free will is an illusion and teaches meditation.
• Sampling Taking a piece of an existing recording and reusing it in a new piece of music. A producer might loop two seconds of a 1970s drum beat and rap over it, or cut up a singer's voice into a new melody. It became central to hip hop in the late 1970s and 1980s, once machines called samplers made it easy, and it has raised ongoing questions about copyright.
• Schizoanalysis A way of looking at desire, meant as an alternative to classic psychoanalysis. Freud tended to trace every wish back to the family, to mother and father. Schizoanalysis says desire is more like a factory: always producing, and plugged into money, politics, machines and society at large, not just home life. Gilles Deleuze and Félix Guattari proposed it in their 1972 book Anti-Oedipus.
• Science A way of learning how the world works by testing ideas against careful observation. You make a guess, called a hypothesis, then design a test that could prove it wrong, like checking whether plants grow faster with more light. If results hold up when others repeat the test, the idea gains support. The modern method took shape in Europe in the 1500s and 1600s with figures like Galileo.
• Self-reflexivity When something turns back and looks at itself. A film that shows its own camera crew, or a novel whose characters know they are in a book, is self-reflexive. For people, it means noticing how your own background and assumptions shape what you see, the way a researcher might ask how their presence changes the people they study. Sociologists like Pierre Bourdieu stressed it in the late 1900s.
• Semiotic Communication The idea that living things, not just humans, communicate through signs. A bee dances to show others where flowers are, a plant releases a chemical that warns its neighbours of insects, and a dog reads a wagging tail. Biosemiotics, a field that grew from the work of Jakob von Uexküll in the early 1900s and Thomas Sebeok later, studies life as a constant exchange of meaningful signals.
• Semiotics The study of signs: anything that stands for something else. A red traffic light means stop, a thumbs-up means good, and a logo stands for a company. Semiotics asks how these meanings are made and shared, often by habit and culture rather than nature. It was founded separately around 1900 by the Swiss linguist Ferdinand de Saussure and the American philosopher Charles Sanders Peirce.
• Sexuality The part of human life that has to do with sexual feelings, attraction and relationships, and how people understand themselves in those terms. It includes who someone is drawn to, how they express it, and how their culture treats it. Ideas about sexuality change over time; the French thinker Michel Foucault argued in 1976 that categories like "heterosexual" and "homosexual" were shaped by history, medicine and law.
• Sigmund Freud Sigmund Freud (1856–1939) was an Austrian neurologist who founded psychoanalysis, a way of treating mental distress by talking. His best-known idea is the unconscious: thoughts and wishes we are not aware of that still steer what we do, and slip out in dreams, jokes and slips of the tongue. He set this out in The Interpretation of Dreams (1899).
• Signification The process by which something comes to mean something. Smoke signifies fire, a wedding ring signifies marriage, and the word "dog" signifies a furry animal. In each case there is the sign itself and the meaning it calls up. Ferdinand de Saussure described this in the early 1900s, and later thinkers like Roland Barthes showed how everyday things, from ads to clothes, carry extra layers of meaning.
• Silence The absence of sound, or the choice not to speak. Silence can mean many things: respect at a memorial, awkwardness in a conversation, or protest when someone refuses to answer. It also shapes sound itself, the way rests give rhythm to music. The composer John Cage's 1952 piece 4′33″, in which a performer plays nothing, showed that true silence is never really empty.
• Simulation A copy that no longer points back to any original, until the copy feels more real than the real thing. Think of a theme park's "Main Street" that looks more like an ideal old town than any actual town ever did. The French thinker Jean Baudrillard argued in his 1981 book Simulacra and Simulation that media and advertising now fill our world with such copies, called simulacra.
• Slavoj Žižek Slavoj Žižek (born 1949) is a Slovenian philosopher and cultural critic known for mixing psychoanalysis, Marxism and popular culture. He uses films, jokes and advertising to explain ideology, the hidden beliefs that shape how we see the world. One of his points is that we often know something is false, like a brand's promise, yet still act as if we believe it. He writes and speaks widely.
• Social construction The idea that many things we treat as natural are actually built by people agreeing on them. Money is a clear example: a banknote is just paper, but it has value because everyone accepts it does. Ideas like nationality, childhood, gender roles or race have changed a lot across times and places. The sociologists Peter Berger and Thomas Luckmann made the idea well known in 1966.
• Sociology The study of how people live together in groups and societies. Sociologists look at patterns bigger than any one person, like why some neighbourhoods are richer, how families change over time, or why certain fashions spread. The word was coined by the French thinker Auguste Comte in the 1830s, and the field was built up by Émile Durkheim, Max Weber and Karl Marx.
• Solipsism The idea that the only thing you can be sure exists is your own mind. Everything else, including other people, might be something like a dream you are having. You can't prove otherwise, since all you ever experience comes through your own thoughts and senses. Few philosophers truly believe it, but it is a famous puzzle that René Descartes' doubts in the 1600s helped sharpen.
• Spiritual Emergence A period of sudden, intense inner change, such as powerful visions, a sense of oneness or overwhelming emotions, that a person experiences as spiritual growth. When it becomes frightening or disruptive, it is called a spiritual emergency, or crisis. The psychiatrist Stanislav Grof and his wife Christina coined the terms in the 1980s, arguing such episodes can lead to healing rather than simply being a mental illness.
• Structuralism A way of studying things by looking at the hidden system of relationships behind them rather than each piece alone. Just as a chess piece means nothing without the rules and board, a word, myth or custom gets its meaning from how it fits a larger structure. It grew from Ferdinand de Saussure's linguistics and spread widely in 1950s and 1960s France through thinkers like Claude Lévi-Strauss.
• Style The recognizable way something is made, which lets you tell who or when it came from. You can often spot a Van Gogh from his thick, swirling brushstrokes, or date a building by its shapes and ornaments. Style can belong to one person, a group, a period or a whole culture. Art historians such as Heinrich Wölfflin, around 1915, tried to describe how styles change over time.
• Subjectivity Seeing things from a personal point of view, shaped by your own feelings, memories and experience. Whether a song is beautiful is subjective; whether it lasts three minutes is objective, meaning it holds true no matter who checks. Philosophers use "subjectivity" for what it is like to be a self with an inner life at all, a question sharpened by René Descartes in the 1600s.
• Superintelligence (ASI) A possible future computer system that would be far smarter than the smartest humans in almost every way, from science to planning to persuasion. Think of how much more a person understands than a mouse; superintelligence would stand in that relation to us. The Swedish philosopher Nick Bostrom's 2014 book Superintelligence made the idea widely discussed, along with the question of how to keep it safe.
• Surface/Depth A contrast between what is visible on the outside and what lies hidden underneath. We often assume the surface is shallow and the truth lies deeper, as when we say someone's smile hides their real feelings. Some thinkers, like Friedrich Nietzsche in the 1880s and later critics of modern culture, questioned this, suggesting surfaces, looks and appearances can matter just as much as any hidden depth.
• Synchronistic Describing a meaningful coincidence: two events that seem connected by meaning even though neither caused the other. You think of an old friend you haven't seen in years, and a minute later they call. The Swiss psychiatrist Carl Jung coined the term synchronicity in the 1920s and wrote about it in 1952, suggesting such moments reveal hidden patterns linking the mind and the outer world.
• Syncretism The blending of different beliefs, religions or cultures into something new. In the Caribbean, for example, Vodou mixed West African spiritual traditions with Catholic saints, so one figure could be both an African spirit and a Christian saint. Syncretism happens wherever cultures meet through trade, travel or conquest, and it is also seen in food, music and language.
• Søren Kierkegaard A Danish philosopher and religious thinker (1813–1855), often called the first existentialist, meaning someone who starts from the lived life of a single person. He said no system or crowd can choose for you: each person must make their own commitments, especially about faith, without proof. He described anxiety as the dizziness we feel when facing our own freedom.
• Technology The tools, machines and methods people invent to solve problems or get things done. It covers everything from a stone axe and a wheel to smartphones and vaccines. Technology changes how we live and even how we think; the printing press, around 1440, reshaped how knowledge spread, much as the internet does now. The word comes from Greek for "the study of craft or skill."
• Television A system for sending moving pictures and sound over a distance to screens in people's homes. Working TV was first shown in the 1920s by inventors such as John Logie Baird and Philo Farnsworth, and it spread widely after the Second World War. Because families watched the same shows at the same time, it shaped news, politics and shared culture for decades, as the internet does today.
• The differend A disagreement that cannot be settled fairly, because the two sides do not share rules or even a language for judging it. Imagine a dispute over sacred land judged only by property law: one side's reasons simply do not count as reasons in that court. The French philosopher Jean-François Lyotard described this in his book The Differend (1983).
• The Enlightenment A movement in 17th- and 18th-century Europe that trusted reason, science and evidence over tradition and religious authority. Its thinkers argued for free speech, religious tolerance and the rights of individuals, ideas that fed the American and French revolutions. The German philosopher Immanuel Kant summed it up in 1784 with the motto "Dare to know": think for yourself.
• The individual A single person seen as separate and distinct from others, with their own thoughts, rights and choices. Many modern societies put the individual first, for example in the idea that each person gets one vote or can choose their own career. Other traditions put the family or community first. The balance between the two is an old debate in politics and ethics.
• The Real The part of life that can't be put into words or pictures. We make sense of the world with language and images, but something always slips through, like the shock of a sudden accident or loss that no explanation quite covers. The French psychoanalyst Jacques Lacan named this leftover "the Real" in the 1950s, separating it from the world of symbols and the world of images we build.
• The Unconscious The part of the mind that works without our awareness, holding thoughts, memories and wishes we can't directly reach. A slip of the tongue, a strange dream or a sudden fear with no clear cause might come from it. Sigmund Freud, the Austrian doctor who founded psychoanalysis around 1900, made the idea famous, arguing that much of what drives us is hidden from ourselves.
• Theatre A live art form where performers act out a story in front of an audience, in the same room at the same time. It uses actors, speech, movement, costume, lighting and a stage or other space. Unlike film, each performance is a little different. Western theatre traces back to ancient Greece around 500 BCE, while traditions like Japanese Noh and Indian Sanskrit drama grew separately.
• Theology The careful study of God, or the divine, and of religious belief. Theologians ask questions like why a good God would allow suffering, or what sacred texts really mean, and try to answer them with reasoning, history and scripture. It is often tied to a specific faith, such as Christian, Islamic or Jewish theology, and was a central subject in the first European universities in the 1100s.
• Tradition A belief, custom or way of doing things passed down from one generation to the next. Family holiday recipes, wedding rituals and folk songs are all traditions. They give people a sense of belonging and continuity, but they also change as they are handed on, and some that feel ancient are fairly recent. Historians Eric Hobsbawm and Terence Ranger called these "invented traditions" in 1983.
• Truth What makes a statement match how things really are. "It is raining" is true if it is actually raining outside. Philosophers disagree on what truth is: some say it is matching the facts, others say it is what fits with everything else we know, and others say it is whatever works in practice. The question goes back at least to Plato and Aristotle in ancient Greece.
• Versions Different forms of the same work or idea, each changed a little from the others. A song might exist as a demo, a studio recording, a live performance and a remix; a story might be retold many times with new details. Versions raise the question of which one is the "real" work, or whether the work is really the whole family of versions together.
• Virtuality Something that is real in effect or potential, even though it is not physically present. A video game world is virtual: you can move through it, but you can't touch it. Philosophers use the word more broadly for real possibilities not yet realized, the way a seed virtually holds a tree. Henri Bergson in the early 1900s and later Gilles Deleuze developed this idea.
• Yuval Noah Harari Yuval Noah Harari (born 1976) is an Israeli historian and author. In his bestseller Sapiens (2011) he argues that humans came to rule the planet because we can cooperate in huge numbers by believing shared stories, such as money, nations and laws, which exist only because we agree they do. His later books ask how technology may change humanity's future.