Ideas

The Arche (the underlying stuff)

What is the one substance behind the many things we see?

Logos

The rational order through which the world coheres.

Flux

Everything flows; nothing stays.

Being

What is, is. What is not, is unthinkable.

Atomism

The world is made of indivisible particles in empty space.

The Socratic Method

Ask, don't tell. Define and refute until knowledge proves itself or fails.

The Examined Life

The unexamined life is not worth living.

The Forms

Eternal, perfect originals of which everything in this world is a copy.

The Allegory of the Cave

We mistake shadows for the real world.

The Philosopher-King

Cities will know peace when philosophers rule, or kings learn philosophy.

The Four Causes

What it's made of, what it is, what made it, what it's for.

Virtue Ethics

The good life is the life of cultivated excellence of character.

The Unmoved Mover

There must be a first cause that itself is uncaused.

Ataraxia

Tranquillity. Freedom from disturbance.

Stoic Virtue

Virtue is the only good. Everything else is preferred or dis-preferred 'indifferents'.

The One

Beyond being. The unsayable source from which everything emanates.

The Inner Self

I have become a great question to myself.

Evil as Privation

Evil is not a thing. It is the absence of a good that should be there.

The City of God

Two cities, founded by two loves: the love of God and the love of self.

Essence vs. Existence

What a thing is, vs. that it is.

The Five Ways

Five compact arguments for the existence of God.

Natural Law

Moral law is rooted in human nature and accessible to reason.

Ockham's Razor

Do not multiply entities beyond necessity.

Nominalism

Universals are names, not things.

Realpolitik

Politics by what works, not by what ought.

Fortuna & Virtù

Half is chance; the other half is what you do with chance.

Induction

Build up from observed particulars to general laws.

Idols of the Mind

Four families of cognitive bias that distort human reasoning.

Cogito, ergo sum

I think, therefore I am.

Mind-Body Dualism

Mind and body are two essentially different kinds of stuff.

Methodic Doubt

Doubt everything that can be doubted until you find what cannot.

Substance Monism

There is only one substance. Everything is a mode of it.

Deus sive Natura

God, or Nature — two names for the same thing.

Tabula Rasa

The mind at birth is a blank slate, written on by experience.

Natural Rights

Life, liberty, and property — by nature, not by grant of the state.

Consent of the Governed

Legitimate authority comes only from those it governs.

Best of All Possible Worlds

A perfect God chose this world; therefore it is the best one possible.

The Monad

An indivisible, perspectival, soul-like atom of reality.

Principle of Sufficient Reason

Nothing happens without a reason why it is so rather than otherwise.

The Bundle Theory of the Self

There is no inner observer. Only a bundle of perceptions.

Causation as Custom

We don't perceive causes. We perceive sequences and form habits.

The Is-Ought Problem

You cannot derive an ought from an is.

The Noble Savage

Humans are born good. Society corrupts them.

The General Will

The collective will aimed at the common good — not the sum of private wills.

The Social Contract

Legitimate society is a contract among equals to live by a common will.

Things-in-Themselves

What things are independent of how they appear to us. Forever unknown.

The Synthetic A Priori

Knowledge that is both genuinely informative and known independent of experience.

The Categorical Imperative

Act only on a maxim you could will to be universal law.

The Dialectic

Every concept generates its opposite. Their tension resolves at a higher level.

Geist (Spirit)

The collective mind of humanity, gradually realizing its own freedom.

The Master-Slave Dialectic

Self-consciousness arises only through being recognized by another.

The Will to Live

Beneath the world of appearance, a blind, purposeless striving.

Philosophical Pessimism

Existence is a problem to be endured, not a gift to be celebrated.

The Leap of Faith

Some commitments cannot be made on the basis of reasons.

Anxiety (Angst)

The dizziness of freedom.

Alienation

Under capitalism, workers become strangers to their work, their products, and themselves.

Truth Is Subjectivity

What matters most cannot be known objectively. It can only be lived.

Class Struggle

All hitherto existing history is the history of class struggles.

The Harm Principle

The only legitimate use of power against an individual is to prevent harm to others.

Historical Materialism

Material conditions of production shape consciousness, not the other way around.

The Principle of Utility

The right action is the one that maximizes the happiness of those affected.

Higher and Lower Pleasures

It is better to be Socrates dissatisfied than a fool satisfied.

God Is Dead

We have killed Him — and we do not yet know what we have done.

Eternal Recurrence

Live so that you could will to live this same life over, infinitely.

The Übermensch

The human being who creates their own values rather than inheriting them.

Will to Power

All life is the will to grow, expand, dominate, become more.

Phenomenology

The rigorous description of experience from the first-person point of view.

Intentionality

Consciousness is always consciousness of something.

Theory of Descriptions

'The present king of France is bald' is meaningful — because it is logically complex.

Epoché (Bracketing)

Suspend the assumption that what you experience is or is not real.

Logical Atomism

Reality breaks down into the simplest facts; the world is everything that is the case.

Picture Theory of Language

A sentence is true if it pictures the world correctly.

Dasein

Being-there: the kind of being that we are, for whom Being is a question.

Being-Toward-Death

Authenticity comes from resolutely facing one's own finitude.

Thrownness (Geworfenheit)

We did not choose to be born, in this body, into this language, this century.

The Absurd

The collision between our hunger for meaning and the universe's silence.

The Myth of Sisyphus

One must imagine Sisyphus happy.

Bad Faith (mauvaise foi)

The lie one tells oneself in order to escape freedom.

Radical Freedom

We are condemned to be free.

Existence Precedes Essence

First we exist, then we make ourselves.

Ethics of Ambiguity

We are at once free subjects and conditioned objects. Ethics begins there.

The Other

Identity is constructed in relation to the one who is not Me.

One Becomes a Woman

Womanhood is a situation, not a destiny.

Metaphysical Revolt

I rebel, therefore we are.

Language-Games

Meaning is use within a form of life.

The Private Language Argument

A language only you could understand is not a language at all.