What Is Real?

What is real?

A rock seems real.

A dream seems less real.

A number is real in a different sense.

A corporation can:

• own property,
• sign contracts

without being a physical object like a chair.

Reality may not be one simple category.

Ontology

Ontology asks:

what exists?

It is one of the oldest branches of metaphysics.

The question is not merely:

What can we observe?

It is:

What kinds of things must we say are real?

Ontological Commitment

When a theory says:

electrons exist,

it commits to electrons.

When mathematics quantifies over:

numbers, sets,

does it commit us to those too?

This is the problem of ontological commitment.

Quine

W. V. O. Quine famously linked ontology to quantification.

Roughly:

to be is to be the value of a bound variable.

If our best theory says:

there exists an x such that…

we take x seriously.

Reality and Observation

We observe:

instrument readings, tracks, effects.

We rarely observe fundamental entities directly.

Reality therefore extends beyond immediate perception.

Electrons

No one sees an electron with naked eyes.

We infer electrons from:

• repeatable experiments,
• successful theory.

Indirect evidence can support realism.

Scientific Realism

Scientific realism says successful scientific theories aim to describe a mind-independent world.

Unobservable entities such as:

• electrons,
• fields

can be genuinely real.

Instrumentalism

Instrumentalism is more cautious.

A theory may be a useful predictive instrument without literally describing hidden reality.

The equations work.

Ontology may be secondary.

No-Miracles Argument

Realists ask:

Why are mature scientific theories so predictively successful?

One answer:

because they approximately describe real structure.

Otherwise success would seem miraculous.

Pessimistic Meta-Induction

Critics point out that many past successful theories contained entities later rejected.

Examples include:

• phlogiston,
• caloric.

Success does not guarantee ontology.

Structural Realism

A compromise is structural realism.

Perhaps science reliably captures:

relations, structure

even when its picture of underlying entities changes.

Entity Realism

Another view says we should be realist about entities we can manipulate reliably.

If electrons can be used to produce controlled effects, that supports their reality.

Mind-Independent Reality

A central realist intuition is:

the world does not disappear when nobody looks.

Mountains existed before humans.

Reality is not created by ordinary observation.

Observer Dependence

Yet some properties depend on observers.

Color depends partly on:

• visual systems,
• illumination.

Does that make color unreal?

Not necessarily.

Relational Reality

A property can be real as a relation.

Velocity is relative to reference frame.

That does not make velocity imaginary.

Observer-dependence and unreality are different.

Social Reality

Money has value because people collectively treat it as valuable.

Its social status is constructed.

But bank balances have real effects.

Social construction does not mean fiction.

Institutional Facts

John Searle distinguished brute facts from institutional facts.

A piece of paper is physically paper.

Within institutions it can be:

currency.

The second fact depends on collective rules.

Corporations

A corporation is not one physical object.

It is a legally and socially organized entity.

It can:

• persist,
• own assets,
• incur obligations.

This is a real higher-level pattern.

Nations

Nations depend on:

• people,
• institutions,
• borders,
• narratives.

They are socially constructed.

Yet wars and laws show their causal reality.

Emergent Reality

Earlier we saw that higher-level properties can be real without being fundamental.

Temperature is real.

It emerges from molecular dynamics.

Reality can be layered.

Reduction Does Not Eliminate

If temperature reduces to molecular statistics, it does not become unreal.

Likewise:

mind, life, economy

may be real at higher levels.

Dennett’s Real Patterns

Daniel Dennett proposed that a pattern is real when it supports:

• compression,
• prediction.

A chess strategy is not a particle.

But recognizing it explains behavior.

Pattern Realism

This suggests reality includes stable higher-level patterns.

Not every real thing must be fundamental.

Fictional Entities

Sherlock Holmes does not exist as a historical detective.

Yet statements about Holmes can be:

• true within the fiction.

Fiction has structure without literal external existence.

Possible Worlds

Modal logic talks about:

possible worlds.

Are these real?

David Lewis famously defended modal realism:

possible worlds are as real as ours.

Most philosophers find this ontologically expensive.

Abstract Objects

What about:

• numbers,
• sets,
• propositions?

Platonists say abstract objects are real.

Nominalists reject them as independent entities.

Mathematical Platonism

On Platonism:

2

exists independently of minds.

Mathematics discovers abstract reality.

Nominalism

Nominalists try to explain mathematics without committing to abstract entities.

Numbers may be:

• symbols,
• linguistic devices.

The debate remains open.

Fictionalism About Mathematics

Mathematical fictionalists treat mathematical discourse as useful without literal commitment to abstract objects.

The mathematics can work even if numbers are not entities.

Properties

Does:

redness

exist?

Or only red things?

Realists about universals say properties are real.

Nominalists say categories are constructed from particulars.

Universals

A universal is a repeatable property:

redness, triangularity.

How can the same property occur in many objects?

This is the problem of universals.

Tropes

Trope theory says each object has its own particularized property instance.

This apple has:

this redness.

Another apple has:

another redness.

Similarity links them.

Events

Are events real?

A storm is not an object in the same way as a rock.

It is a temporally extended process.

Ontology may need:

• objects,
• events.

Processes

Process philosophy emphasizes change rather than static substances.

Maybe the fundamental reality consists of:

events, relations.

Objects become relatively stable processes.

Fields

Modern physics describes fields extending through space.

Particles may be excitations of fields.

Everyday object ontology may be far from fundamental physics.

Quantum Fields

In quantum field theory, particle number can change.

Fields appear more fundamental than classical particles.

But interpreting the ontology of QFT remains philosophically difficult.

Wavefunction

Is the quantum wavefunction real?

Some interpretations treat it as physical.

Others treat it as:

• information,
• knowledge.

Quantum ontology is contested.

Spacetime

General relativity treats spacetime geometrically.

Is spacetime a substance?

Or merely relations among events?

This revives the old substantivalism–relationalism debate.

Relationalism

Relationalists say space is constituted by relations among physical things.

No independent container is needed.

Substantivalism

Substantivalists treat spacetime points or structure as real in their own right.

Modern physics does not automatically settle the metaphysics.

Consciousness

Is subjective experience real?

Even illusionists must explain:

• reports,
• self-models.

Phenomenal realists say experience is among the most undeniable realities.

The Self

Is the self real?

It may not be a simple indivisible substance.

But a constructed self-model can still be a real causal pattern.

Illusion ≠ Unreal Process

If the self is an illusion, the mechanisms generating that illusion are real.

The word “illusion” often hides ontological ambiguity.

Levels of Reality

We can distinguish:

• fundamental,
• biological,
• psychological,
• social.

Reality may be plural across levels.

Dependence

A social fact depends on physical systems.

This does not make it nonexistent.

Dependence is not unreality.

Grounding

Metaphysicians use grounding for relations of metaphysical dependence.

Example:

the fact that a table exists may be grounded in arrangements of particles.

Grounding is not ordinary causation.

Grounding vs Causation

Particles do not cause the table to exist in the same temporal sense that fire causes smoke.

They constitute or ground it.

This mirrors earlier brain–consciousness distinctions.

Fundamentality

Some entities may be more fundamental than others.

But:

less fundamental

does not mean:

less real.

A hurricane is real despite depending on molecules.

Ontological Parity

Some philosophers resist ranking reality.

If an entity participates in true explanations, perhaps it is simply real.

Fundamentality is one property among others.

Realism About Everyday Objects

Physics tells us tables are mostly empty space.

Does that mean tables are not real?

No.

“Solid table” is a higher-level description of electromagnetic and quantum structure.

Manifest Image

Wilfrid Sellars distinguished the manifest image:

the world of:

• people,
• objects,
• colors.

from the scientific image:

theoretical scientific ontology.

Scientific Image

Science describes:

• fields,
• particles,
• spacetime.

The challenge is integrating both images.

Neither can simply be ignored.

Eliminativism

Sometimes science removes an entity.

Phlogiston was abandoned.

So some higher-level concepts genuinely fail.

Reality should not be granted merely because a word exists.

Criteria for Reality

Possible criteria include:

• causal power,
• explanatory necessity,
• predictive value,
• independence from belief.

No single criterion works perfectly for every domain.

Causal Criterion

If something has causal effects, it seems real.

But abstract numbers appear causally inert.

Are they therefore unreal?

The criterion has limits.

Explanatory Criterion

If an entity appears indispensably in our best explanations, perhaps we should accept it.

This supports scientific realism.

Indispensability Argument

Quine and Putnam argued that because mathematics is indispensable to science, we should accept mathematical entities along with scientific ones.

The argument is controversial.

Fictional Use

Critics reply that a concept can be useful without literal ontological commitment.

Models often idealize nonexistent objects.

Utility alone is insufficient.

Mind Dependence

Some things exist only because minds exist.

Examples:

• laws,
• money,
• games.

They are still real within social systems.

Objective vs Subjective

Reality is not divided cleanly into:

objective = real, subjective = unreal.

Pain is subjective and real.

Currency is intersubjective and real.

Intersubjective Reality

An intersubjective fact exists because many agents coordinate around it.

Institutions belong here.

This is a distinct mode of reality.

Virtual Objects

A digital object can have:

• persistence,
• ownership,
• causal effects.

Does a file exist?

Certainly in an ordinary sense.

It is realized through physical states.

Software

Software is not identical to one physical device.

The same program can run on different hardware.

It is a real abstract-functional pattern.

Multiple Realizability Again

A real entity may be realized in many physical forms.

This supports higher-level ontology.

Reality and Models

A model is not the world.

But models may successfully refer to real structures.

We need not choose between:

perfect representation

and:

pure fiction.

Approximate Truth

Scientific realism often accepts approximate truth.

A model can be wrong in detail while capturing important structure.

Newtonian mechanics is the classic example.

Reality Beyond Access

A mind-independent world may contain structures humans cannot directly perceive or conceptualize.

Epistemic limits do not imply ontological limits.

Humility

We should separate:

what exists

from:

what we can currently know exists.

Ontology exceeds epistemology.

The Beginning of Part XIX

The final section returns to our opening questions.

After:

• physics,
• information,
• mind,
• belief,

we ask what all these descriptions are descriptions of.

The Philosophical Lesson

Reality is not one homogeneous category.

It may include:

• fundamental entities,
• emergent patterns,
• subjective experiences,
• social institutions.

The hard task is deciding which ontological commitments our best explanations genuinely require.

The Next Question

Even if reality exists independently of us, we never encounter it without mediation.

We encounter:

appearances.

How should we distinguish what seems to be from what is?

The next essay is:

Reality and Appearance.