Metaphysics

Realism

The view that universals exist as repeatable entities independent of the particulars that instantiate them.

Nominalism

The rejection of universals; only particulars (or classes of particulars) exist.

Carnapian Non-Cognitivism

The claim that "external" questions about the reality of properties are pseudo-questions; choices between frameworks are based on practical utility, not theoretical truth.

Russell’s Theory of Descriptions

A method of analyzing sentences with definite descriptions (like "the current King of France") to show they are not names for existing entities but are instead existential quantifications.

The One Over Many Argument

A classic argument for realism stating that if multiple things share a common trait (like being "red"), there must be a single universal "Redness" they all share.

Just-Matter Theory

The claim that only quantities of matter exist; objects are identical to their parts.

Takeover Theory

The view that only one "sort" of object (e.g., a statue vs. clay) can control a group of particles at any given time.

Three-Dimensionalism

Objects are "wholly present" at every moment they exist.

Four-Dimensionalism

Objects are "spacetime worms" with distinct temporal parts spread throughout time.

Presentism

Only the present is real.

Eternalism

Past, present, and future events are all equally real in a 4D block universe.

Growing Block

The past and present are real, but the future is not.

Moving Spotlight

The universe is an eternalist block, but there is an objectively privileged "present" that moves across it.

Chisholm

Argues that objects (in a strict sense) do not survive the loss or change of their parts.

Kripke

Argues that objects exist in multiple possible worlds because names are "rigid designators" that refer to the same thing in every possible scenario.

Problem of the Many

The difficulty of identifying a single object (like a cloud) when there are many slightly different aggregates of particles that could qualify.

Grandfather Problem

A paradox of time travel where a traveler's actions in the past could prevent their own existence.

Modal Realism

The view that other possible worlds exist as concrete physical entities.

Actualism

The view that only the actual world is real; possible worlds are just abstract descriptions.

Humeanism

Laws are descriptive patterns—the "best system" for summarizing facts.

Anti-Humeanism

Laws are governing relations between universals that "make" things happen.

Theory of Causal Powers

The claim that properties are defined by the causal potentials they bestow upon objects.

Fatalism

The view that the future is fixed and inevitable.

"Open Future"

The view that future events are not yet settled.

Determinism

The thesis that the laws of nature and the past determine one unique future.

Compatibilism vs. Incompatibilism

The debate over whether moral responsibility can coexist with determinism.

Principle of Alternate Possibilities

The idea that you are responsible only if you could have done otherwise.

Frankfurt’s Counterexamples

Cases where an agent is responsible despite having no alternative (e.g., because a "counterfactual intervener" would have forced them to act if they hadn't chosen to do so on their own).

Autographic Art

Arts where the history of production matters and forgeries are possible (e.g., painting).

Allographic Art

Arts that use a notation system; any correct performance or "spelling" counts as the work itself (e.g., music or literature).