Philosophy
Logic, ethics, metaphysics, and deep questions. Every concept visualized with interactive 3D animations.
A Priori vs A Posteriori Knowledge · Justification before experience vs after
A priori knowledge is justified independently of sensory experience: 2 + 3 = 5, the law of non-contradiction, “all triangles have three sides.&r
EpistemologyAbstract Objects & Platonism · Are numbers as real as rocks? The case for a non-physical universe of mathematical things
Platonism in metaphysics is the view that abstract objects — numbers, sets, propositions, properties — exist mind-independently outside space and time
MetaphysicsAnalytic vs Synthetic Distinction · Truth by meaning vs truth by world
An analytic truth is true purely in virtue of the meanings of its terms — “all bachelors are unmarried” needs no fact-checking. A syntheti
EpistemologyAnimal Ethics · Sentience, suffering, and the moral status of non-human animals
Animal ethics is the branch of moral philosophy that asks whether non-human animals have moral status and what humans owe them. The modern field cryst
EthicsAristotle's Four Causes · Four answers to "why is it so?"
Aristotle held that to know a thing fully, you must give four kinds of explanation: what it's made of, what it is, what brings it about, and what it's
Ancient PhilosophyAristotle's Golden Mean · Virtue as the mean between two opposing vices
The Golden Mean (mesotēs) is Aristotle's doctrine that each moral virtue is a mean between two corresponding vices — one of excess, one of deficiency.
Ancient PhilosophyBehaviorism · Mind as Behavior
Early 20th century: ignore inner mental states; catalog stimulus-response patterns. Skinner's pigeons, Pavlov's dogs, reinforcement schedules. Eventua
Philosophy of MindBrain in a Vat · A skeptical scenario — and Putnam's argument that you can't even think it
The Brain in a Vat is a modern reformulation of Cartesian skepticism: could you be a disembodied brain receiving simulated stimuli, with no real body
EpistemologyBuddhism's Four Noble Truths · Suffering
Dukkha (suffering exists), tanha (craving is its root), nirvana (cessation is possible), and the Eightfold Path (how). The Buddha's diagnosis and pres
Asian PhilosophyCare Ethics (Feminist) · Morality grounded in relationships, not rules
Care ethics is a feminist moral theory that locates the foundation of ethics in particular caring relationships — between parent and child, nurse and
EthicsCategorical Imperative · Kant
3D grid of people each performing an action. Animate testing if the action can become a universal law: if everyone lies, trust collapses (grid turns r
EthicsCausation · Hume on Constant Conjunction
We see A followed by B, over and over. The causal connection itself is invisible — we project necessity onto pattern. Hume's analysis still shapes phi
MetaphysicsChinese Room · Searle's Argument Against Strong AI
A person in a room follows rules to manipulate Chinese symbols without understanding them. Outside observers think the room speaks Chinese. Searle: sy
Philosophy of MindCogito Ergo Sum · I think therefore I am
3D visualization of Descartes' method of doubt. Objects in the scene disappear one by one (senses deceive, world might be a dream) until only a glowin
EpistemologyCoherence Theory of Truth · Truth is fitting in — not pointing out
The coherence theory of truth holds that a proposition is true if and only if it belongs to a maximally coherent system of beliefs. Defended by F.H. B
EpistemologyCompatibilism (Free Will) · Free will and determinism, both at once
Compatibilism is the view that free will and causal determinism are compatible. The free agent isn't one who escapes causation; she's one who acts fro
MetaphysicsConfucius & Ren · Humaneness & the Relationships
Ren (humaneness) cultivated through five reciprocal relationships: ruler-subject, parent-child, husband-wife, elder-younger, friends. Filial piety as
Asian PhilosophyCorrespondence Theory of Truth
The correspondence theory of truth holds that a proposition is true if and only if it corresponds to a fact about the world. The dominant Western view
EpistemologyCosmological Argument · Why is there something rather than nothing?
The cosmological argument is a family of a posteriori arguments for God's existence that begin from the bare fact that the world exists. Where the ont
Philosophy of ReligionCynicism (Diogenes) · Train yourself to need nothing — and the powerful have nothing to offer
Cynicism is the ancient Greek school that took virtue ethics to its most uncompromising end: virtue is sufficient for happiness, virtue is living acco
Ancient PhilosophyDeontology · Duty-Based Ethics
Ethics is about following moral rules, not maximizing outcomes. Kant's universalizability test: if everyone did this, would the practice self-destruct
EthicsDeterminism · Past + laws → one and only one future
Determinism is the thesis that the complete state of the universe at any moment, together with the laws of nature, fixes the complete state of the uni
MetaphysicsDivine Command Theory · Right and wrong are constituted by what God commands
Divine Command Theory (DCT) is the position that an action is morally right because — and only because — God commands it. Wrongness is what God forbid
EthicsDoctrine of Double Effect · When a foreseen harm is permitted, but an intended harm is not
The Doctrine of Double Effect (DDE) holds that an action with both a good and a bad effect can be permissible if the bad effect is foreseen but not in
EthicsEmergentism · The whole becomes something its parts cannot fully explain
Emergentism is the view that some higher-level properties — life, consciousness, social structure — arise from lower-level physical systems but cannot
Philosophy of MindEmotivism (Ayer) · "Killing is wrong" is a boo, not a description
Emotivism is the meta-ethical view that moral utterances express emotional attitudes rather than state facts. A. J. Ayer's Language, Truth and Logic (
Meta-EthicsEnvironmental Ethics · Does a forest matter when no one is watching?
Environmental ethics is the branch of moral philosophy that asks whether the non-human natural world — species, ecosystems, mountains, rivers — has mo
EthicsEpicureanism · Tranquility through modest pleasure, materialist physics, and the Tetrapharmakon
Epicureanism is the Hellenistic philosophy founded by Epicurus (~341–270 BCE) at his Athenian school known as the Garden. Its goal is eudaimonia under
Ancient PhilosophyEthics of AI · Who is harmed and who is helped when systems learn to act
The ethics of AI asks how to build, deploy, and govern artificial systems whose decisions affect human lives. From Nick Bostrom's Superintelligence (2
EthicsEudaimonia (Aristotle) · Flourishing as the activity of a complete human life
Eudaimonia is Aristotle's term in the Nicomachean Ethics (~340 BCE) for the highest human good — usually translated "flourishing" or "living well." It
Ancient PhilosophyExistentialism (Sartre) · Existence Precedes Essence
Unlike objects, humans exist first and define themselves through choices. Radical freedom brings anguish and responsibility. 'Bad faith' is denying th
ExistentialismExternal World Skepticism · Descartes' Evil Demon
How do we know the external world is real? You could be dreaming, brain in a vat, or fed simulations by an evil demon. From inside, a perfect illusion
EpistemologyFalsifiability (Popper) · A theory worth its name forbids something — and risks being wrong
Falsifiability is Karl Popper's proposed criterion for distinguishing scientific from non-scientific theories. A theory is scientific, Popper argued i
Philosophy of ScienceFree Will vs Determinism · choice
3D forking paths at decision points. One side shows a deterministic chain of dominoes falling in a fixed sequence. The other side shows a person choos
MetaphysicsFunctionalism · Multiple Realizability
Mental states are defined by functional role — caused by inputs, causing outputs — not substrate. Any system playing the role has the state. The mind
Philosophy of MindGettier Problem · Justified True Belief Fails
A 3-page 1963 paper by Edmund Gettier broke the 2000-year definition of knowledge as justified true belief. Lucky coincidences can produce JTB without
EpistemologyHard Problem of Consciousness · Why Does Experience Feel Like Something?
The 'easy problems' — how the brain processes information — yield to science. The hard problem: why is there subjective experience at all? Chalmers' e
Philosophy of MindHedonism · Pleasure as Highest Good
Epicurus distinguished sustainable tranquility (ataraxia) from intense short-lived pleasure. Simple food, friends, reflection over fame and luxury. Mo
Philosophy of LifeHeidegger's Being and Time · The hammer that disappears when you use it
In Sein und Zeit (1927), Martin Heidegger argues that the question of Being has been forgotten. He approaches it through Dasein — the human being whos
Continental PhilosophyIs-Ought Problem · Hume's Guillotine
You can't derive an 'ought' from an 'is' by pure logic. Descriptive facts don't entail normative conclusions without a normative premise. Central meth
EthicsJust War Theory · Jus ad Bellum & Jus in Bello
When is war justified (just cause, last resort), and how must it be fought (discrimination, proportionality, no evil means)? Augustine, Aquinas, and m
PoliticalLanguage Games (Wittgenstein) · Don't ask what a word means — ask how it's played
Ludwig Wittgenstein's later philosophy abandoned the picture theory of his Tractatus and replaced it with "language games" — meaning is use within a f
Philosophy of LanguageLiar Paradox · Five words that broke 2,400 years of logic
The liar paradox arises from a sentence that asserts its own falsity: this sentence is false. If it's true, it's false; if it's false, it's true. Pose
LogicLogical Fallacies · Common Bad Arguments
Ad hominem, straw man, false dichotomy, slippery slope. Bad arguments that feel persuasive by exploiting emotion, tribalism, and cognitive shortcuts.
LogicMarx's Theory of Alienation · Why your own labour can come to feel like a stranger
Marx's theory of alienation, set out in the 1844 Economic and Philosophic Manuscripts, claims that wage labour under capitalism severs the worker from
Political PhilosophyMary's Room (Knowledge Argument) · A black-and-white scientist meets red — does she learn something new?
Mary the colour scientist knows every physical fact about red but has lived her entire life in a black-and-white room. When she finally sees a red ros
Philosophy of MindMeta-Ethics · Do Moral Facts Exist?
Realism: moral facts are objective like math. Error theory: all moral claims are false. Expressivism: moral talk expresses emotion. Constructivism: mo
EthicsMind-Body Problem · Dualism vs Materialism
Is the mind a separate substance from the body? Descartes said yes (dualism); materialism says no — the mind IS the brain. Each view has intractable p
MetaphysicsModal Realism · All Possible Worlds Exist
David Lewis argued all logically possible worlds are as real as ours. Counterfactuals are made true by what happens in the nearest world where the ant
MetaphysicsModus Ponens · If P then Q, P, therefore Q
Classical logic's simplest valid form. Also: modus tollens (P→Q, ¬Q, therefore ¬P). Affirming the consequent is the sibling fallacy. These rules are t
LogicMoral Luck · Judged by Accident
Two drivers equally drunk. One arrives home. One kills a child. Same act, same character, wildly different judgment. Nagel showed morality is saturate
EthicsMoral Realism · Some moral claims are true — and not because we say so
Moral realism is the meta-ethical view that there are mind-independent moral facts and that some moral statements are objectively true. The realist ta
Meta-EthicsMoral Relativism · Ethics Varies by Culture
Different cultures hold different moral codes. Normative relativism says no culture is objectively better — tolerance at the cost of being unable to c
EthicsNatural Law Theory · A law above the laws — written into human nature, read by reason
Natural law theory holds that moral norms are grounded in human nature and accessible to reason — that there is a law above human law that no decree c
EthicsNatural Rights · Life
Locke's unalienable rights — possessed by every person in virtue of being human, not granted by government. Government's job is to protect them. Found
PoliticalNecessary vs Contingent Truths · What couldn't have been otherwise vs what could
A necessary truth holds in every possible world: 2 + 2 = 4, “triangles have three sides,” on Kripke's account “water is H₂O.&r
MetaphysicsNeoplatonism (Plotinus) · Reality as overflow from a source beyond being
Neoplatonism is a third-century philosophical synthesis founded by Plotinus (c. 204–270 CE) that recasts Plato's metaphysics around a single, ineffabl
Ancient PhilosophyNietzsche's Eternal Recurrence · Could you bear this life, exactly as it is, returning forever?
The eternal recurrence is Nietzsche's thought experiment that this same life — every joy, every pain, every detail — repeats infinitely. He calls it t
Continental PhilosophyNietzsche's Übermensch · Beyond Slave Morality
After 'God is dead,' most settle into herd conformity (the 'last man'). Nietzsche's higher ideal: create your own values, overcome yourself, embrace e
ExistentialismNozick's Libertarianism · Why a million voluntary trades can wreck any pattern of justice
Robert Nozick's libertarianism, set out in Anarchy, State, and Utopia (1974), defends the minimal state on the basis of inviolable individual rights a
Political PhilosophyOccam's Razor · Among rival explanations, prefer the one that buys less ontology
Occam's Razor — also called the principle of parsimony or lex parsimoniae — says: when two hypotheses explain the same evidence, prefer the one that p
LogicOntological Argument (Anselm) · Proving God exists from the definition alone
The ontological argument is an a priori proof for God's existence that starts from the concept of God alone — no appeal to the world, no observed fact
Philosophy of ReligionPanopticon · Surveillance & Discipline
Bentham's circular prison design where inmates never know when they're watched — so they behave as if always watched. Foucault extended it: modern soc
PoliticalParadigm Shift (Kuhn) · How scientific worldviews break and replace each other
A paradigm shift is the wholesale replacement of one scientific worldview by another. Thomas Kuhn introduced the term in The Structure of Scientific R
Philosophy of ScienceParfit on Personal Identity · Why the question "is it still me?" might not be the question that matters
Derek Parfit's Reasons and Persons (Oxford, 1984) defends two surprising claims about the self. First, persons are nothing over and above interrelated
MetaphysicsPascal's Wager · Betting on infinity with a finite stake
Pascal's Wager is a 17th-century argument that belief in God is the rational bet because the possible payoff is infinite while the cost of being wrong
Philosophy of ReligionPersonal Identity · What Makes You You?
Body, memory, or psychological continuity? A teleporter that splits you into two copies reveals identity's fragility. Parfit argued continuity, not id
MetaphysicsPhenomenology (Husserl) · "To the things themselves" — describing experience before theory tells us what to find
Phenomenology, founded by Edmund Husserl, is the rigorous descriptive study of conscious experience as it is lived. Logical Investigations (1900–01) l
Continental PhilosophyPhilosophical Zombies · Conscious Without Consciousness
A p-zombie is physically identical to you but has no inner experience. Chalmers uses them to argue consciousness isn't reducible to physics. The very
MetaphysicsPhilosophy of Time · Presentism vs Eternalism
Does only the present exist (presentism), or do past, present, and future all equally exist (eternalism/block universe)? Einstein's relativity tilts t
MetaphysicsPlato's Cave · shadows
3D cave with prisoners chained facing a wall. Animate shadows projected by objects behind them, then one prisoner breaks free and turns to see the rea
MetaphysicsPlato's Theory of Forms · Eternal universals behind the changing world of appearance
Plato's Theory of Forms holds that the changing world of sensible particulars is not the deepest reality. Beyond it lies a realm of eternal, unchangin
Ancient PhilosophyPositive & Negative Liberty · Berlin's Two Concepts
Negative liberty: freedom FROM interference. Positive liberty: freedom TO achieve. Welfare programs trade some of the first for more of the second. Be
PoliticalPragmatism · Truth that has to earn its keep — the American tradition of judging ideas by what they do
Pragmatism is the American philosophical tradition that judges concepts and beliefs by their practical consequences. Founded by Charles Sanders Peirce
EpistemologyPrivate Language Argument · Why you can't name the unnameable feeling — even to yourself
Wittgenstein's private-language argument (Philosophical Investigations §§243–315) claims that a language whose words refer to inner sensations knowabl
Philosophy of LanguageProblem of Evil · If God is good and powerful, why does the world look like this?
The problem of evil is the most discussed objection to theism in the Western philosophical tradition. In its sharpest form it claims that God's existe
Philosophy of ReligionProblem of Induction · Hume's Challenge to Science
How do we justify that the future will resemble the past? Any answer seems to assume the principle it's trying to prove. Hume concluded induction is a
EpistemologyRawls' Theory of Justice · Fairness as the Veil of Ignorance
Design society not knowing your race, gender, wealth, or talents. You'd choose principles protecting the worst-off (difference principle). The most in
PoliticalRealism vs Anti-Realism · Is there a world out there, and do our theories really get it right?
The realism debate asks whether there is a world independent of our minds, and whether our best theories describe it accurately. Realism affirms both;
MetaphysicsScience vs Pseudoscience · Popper's Falsifiability
Science makes risky, falsifiable predictions. Pseudoscience accommodates any outcome. Popper's demarcation criterion separates Einstein from astrology
EpistemologyShip of Theseus · identity
3D ship with planks being replaced one by one. Each old plank flies off and a new glowing plank takes its place. After all planks are replaced, ask: i
MetaphysicsSimulation Argument (Bostrom) · Extinction, disinterest, or — we are almost certainly simulated
Nick Bostrom's 2003 simulation argument is not "we live in The Matrix". It is a probabilistic trilemma: if any technologically mature civilisation run
MetaphysicsSisyphus & Absurdism · Camus
3D Sisyphus pushing a boulder up a hill. Each time it reaches the top, it rolls back down. But Sisyphus smiles — Camus says we must imagine him happy.
ExistentialismSocial Contract · Hobbes
Three philosophers imagining government's origin. Hobbes: a Leviathan to escape nasty nature. Locke: protect natural rights. Rousseau: express the gen
PoliticalSocratic Method · questions
3D dialogue tree branching outward. A central question node spawns follow-up questions, each answer reveals assumptions that get challenged. The tree
LogicSorites Paradox (Heap) · If you remove one grain, is it still a heap? — the puzzle of vagueness
The Sorites Paradox asks when a heap stops being a heap as you remove grains one by one. Either every grain matters (which seems false) or some grain
LogicStoicism · Control What You Can
Distinguish what you control (your judgments, effort) from what you don't (others, outcomes). Focus on the first. Epictetus: 'It's not events that dis
Philosophy of LifeSupervenience · No A-difference without a B-difference — dependence without identity
Supervenience is a relation of asymmetric dependence: A-properties supervene on B-properties when no two things can differ in A without differing in B
MetaphysicsTabula Rasa · Blank Slate
Locke argued the mind at birth is empty. All knowledge traces back to experience — no innate ideas. Simple sensations combine into complex concepts. E
EpistemologyTaoism & Wu Wei · Natural Action Without Force
Water flows around rocks and still carves canyons. Wu wei — effortless action aligned with the natural flow. Not passivity; efficacy through alignment
Asian PhilosophyTeleological Argument (Design) · From the watchmaker to fine-tuning
The teleological argument infers a designer from the apparent order, complexity, or purposiveness of nature. The Greek telos means "end" or "purpose";
Philosophy of ReligionThe Golden Rule · Do Unto Others
Treat others as you'd want to be treated. Confucius, Jesus, Hillel, Kant, and the Quran all have versions. Reciprocity as a near-universal moral princ
EthicsTrolley Problem · ethics
3D trolley on tracks heading toward five people. Animate the lever switch diverting it to a side track with one person. Show the moral choice: save fi
EthicsTypes of Knowledge · Knowing-That
Propositional (knowing Paris is in France), procedural (knowing how to ride a bike), and acquaintance (knowing the color red). Three kinds of knowing,
EpistemologyUtilitarianism · Greatest Good for Greatest Number
Right action maximizes happiness across all affected. Bentham and Mill's consequentialist theory underlies modern welfare economics and cost-benefit a
EthicsValid vs Sound · Argument Structure vs Truth
An argument is valid if structure guarantees the conclusion. Sound if valid AND premises are true. 'All birds fly; penguins are birds; penguins fly' —
LogicVeil of Ignorance · Rawls
3D figures behind a translucent veil, unable to see their own attributes (wealth, race, ability). They must design rules for society not knowing where
Political PhilosophyVirtue Ethics · Character Over Rules
Aristotle asked not 'what should I do?' but 'what kind of person should I be?' Virtues sit between deficiency and excess — courage between cowardice a
EthicsYin and Yang · balance
3D rotating yin-yang symbol with opposing forces flowing into each other. Light particles flow into dark and dark into light, showing how opposites co
Eastern PhilosophyZeno's Paradoxes · Why a runner can never finish — and what that says about infinity
Zeno of Elea's paradoxes — Achilles and the Tortoise, the Dichotomy, the Arrow — argue that motion and plurality are illusions. They survived 2,400 ye
Logic