Maxwell: Maxwell: Against EmpiricismAgainst Empiricism

Kareem KhalifaKareem Khalifa

Department of PhilosophyDepartment of Philosophy

Middlebury CollegeMiddlebury College

OverviewOverview

I.I. BackgroundBackground

II.II. Maxwell on the observable-Maxwell on the observable-unobservable distinctionunobservable distinction

I.A. MaxwellI.A. Maxwell’’s main s main line of attackline of attack

1.1. If antirealism is true, then there If antirealism is true, then there must be a clear distinction must be a clear distinction between observable and between observable and unobservable entities. unobservable entities.

2.2. There is no clear distinction There is no clear distinction between observable and between observable and unobservable entities.unobservable entities.

3.3. Therefore, antirealism is false.Therefore, antirealism is false.

I. B. Four kinds of I. B. Four kinds of antirealismantirealism

1.1. FictionalismFictionalism

2.2. InstrumentalismInstrumentalism

3.3. PhenomenalismPhenomenalism

4.4. EliminativismEliminativism

1. Fictionalism1. Fictionalism

FictionalismFictionalism: Beliefs about : Beliefs about unobservable unobservable entities are merely entities are merely useful fictions.useful fictions.

– They are psychological crutches They are psychological crutches that help guide scientists in that help guide scientists in devising experiments, but they devising experiments, but they need not be true or even need not be true or even meaningful in order to fulfill this meaningful in order to fulfill this function.function.

2. Instrumentalism2. Instrumentalism

Commitments to Commitments to unobservable unobservable entities are tools for organizing, entities are tools for organizing, predicting, and controlling predicting, and controlling observable observable entities. As a result, entities. As a result, they’re practical commitments, they’re practical commitments, not beliefs.not beliefs.

– Compare: hammers donCompare: hammers don’’t t meanmean anything; theyanything; they’’re re usedused for certain for certain things.things.

3. Phenomenalism3. Phenomenalism

Sentences about Sentences about unobservable unobservable entities are reducible to sentences entities are reducible to sentences about about observable observable entities. entities.

– Ex. Ex. ““Here are quarksHere are quarks”” is reducible to is reducible to statements about (energy level) statements about (energy level) E and E and (angle) (angle) , etc., etc.

– ““Here is a tableHere is a table”” is reducible to is reducible to statements about statements about ““Something brown Something brown appears to me,appears to me,”” ““Something seems firm Something seems firm to my touch,to my touch,”” etc. etc.

4. Eliminativism4. Eliminativism

Unobservable Unobservable entities should be entities should be removed from our vocabulary, removed from our vocabulary, primarily because there would primarily because there would be no loss in doing so.be no loss in doing so.

MaxwellMaxwell’’s main line of s main line of attackattack

1.1. If antirealism is true, then there If antirealism is true, then there must be a clear distinction must be a clear distinction between observable and between observable and unobservable entities. unobservable entities.

2.2. There is no clear distinction There is no clear distinction between observable and between observable and unobservable entities.unobservable entities.

3.3. Therefore, antirealism is false.Therefore, antirealism is false.

✔

II. MaxwellII. Maxwell’’s challenges challenge

All of these antirealisms depend All of these antirealisms depend on an observable-unobservable on an observable-unobservable distinction.distinction.

But what is unobservable today But what is unobservable today may be observable at a later time, may be observable at a later time, given technological advances, etc.given technological advances, etc.

So none of these antirealisms are So none of these antirealisms are tenable.tenable.

A. Three notions of A. Three notions of observabilityobservability

1.1. Something is observable iff it is Something is observable iff it is expressible as a expressible as a sense-data reportsense-data report..

2.2. Something is unobservable iff the Something is unobservable iff the theorytheory positing it, plus a theory of positing it, plus a theory of perception, entails that it is perception, entails that it is unobservable.unobservable.

3.3. Something is observable iff a Something is observable iff a human, human, unaided by technology,unaided by technology, could could observe it.observe it.

Sense-data approachSense-data approach

Something is observable iff it is Something is observable iff it is expressible as a expressible as a sense-data sense-data reportreport..

Sense data reports are statements Sense data reports are statements about about experiencing experiencing basic observable basic observable properties. Thus, properties. Thus, ““It It appears to meappears to me that something red is here nowthat something red is here now”” would be a sense-data report.would be a sense-data report.

MaxwellMaxwell’’s rebuttals to s rebuttals to the sense-data the sense-data approachapproachB.B. If this is right, then ordinary If this is right, then ordinary

physical objects are theoretical physical objects are theoretical (unobservable).(unobservable).

– That seems absurd!That seems absurd!C.C. The authority of sense-data The authority of sense-data

reports rests on the authority of reports rests on the authority of statements about ordinary statements about ordinary physical objects.physical objects.

– So, the latter can’t be derivative of So, the latter can’t be derivative of the former.the former.

More on Rebuttal CMore on Rebuttal C

1.1. There are “quickly decidable There are “quickly decidable statements,” i.e., statements of which statements,” i.e., statements of which ordinary people can ascertain the ordinary people can ascertain the truth/falsity with little controversy and truth/falsity with little controversy and difficulty. (1060) difficulty. (1060)

2.2. Sentences about Sentences about physical objectsphysical objects are are quickly decidable, and sense data appear quickly decidable, and sense data appear to be theoretical terms that explain these to be theoretical terms that explain these quickly decidable sentences.quickly decidable sentences.

3.3. Thus the reason we believe in sense data Thus the reason we believe in sense data is because they explain quickly decidable is because they explain quickly decidable statements.statements.

ExampleExample

I see an apple.

Because something appears

red to me now.

Why do you think that you see an

apple?

Furthermore…Furthermore…

We can train ourselves to We can train ourselves to directly observe these directly observe these theoretical entities—sense data.theoretical entities—sense data.

So why canSo why can’’t we train ourselves t we train ourselves to directly observe other to directly observe other theoretical entities (e.g., theoretical entities (e.g., gravitational fields)?gravitational fields)?

The theory approachThe theory approach

Something is unobservable iff Something is unobservable iff the theory positing it, plus a the theory positing it, plus a theory of perception, entails that theory of perception, entails that it is unobservable. (1057)it is unobservable. (1057)

Ex. Electrons, quarksEx. Electrons, quarks

MaxwellMaxwell’’s rebuttals to s rebuttals to the theory approachthe theory approach

D.D. This is inconsistent with This is inconsistent with fictionalism and fictionalism and instrumentalism.instrumentalism.

– The statement The statement ““X is unobservableX is unobservable”” would have to be meaningful.would have to be meaningful.

E.E. Our theory of perception might Our theory of perception might be wrong or only right at time be wrong or only right at time tt..

– ““The mutation objectionThe mutation objection””

Rebuttal D: Rebuttal D: fictionalism, fictionalism, instrumentalism, & the instrumentalism, & the theory approachtheory approach

1.1. Theory Approach: Theory Approach: Something is unobservable Something is unobservable iff the theory positing it, plus a theory of iff the theory positing it, plus a theory of perception, entails that it is unobservable.perception, entails that it is unobservable.

2.2. Theories only entail meaningful statements.Theories only entail meaningful statements.

3.3. Fictionalism & instrumentalism deny that Fictionalism & instrumentalism deny that statements about unobservables are statements about unobservables are meaningful.meaningful.

So fictionalism, instrumentalism and the theory So fictionalism, instrumentalism and the theory approach are incompatible.approach are incompatible.

Rebuttal E: The Rebuttal E: The mutation objectionmutation objection

Recall: Recall: Something is Something is unobservable iff the unobservable iff the theory positing it, theory positing it, plus a plus a theory of perceptiontheory of perception, , entails that it is entails that it is unobservable.unobservable.

But our theory of But our theory of perception is a theory of perception is a theory of humanhuman perception, perception,and this is somewhat and this is somewhat arbitrary.arbitrary.

The unaided human The unaided human accountaccount Something is observable iff a Something is observable iff a

human, unaided by technology, human, unaided by technology, could observe it.could observe it.

Thus, there is no way of inferring Thus, there is no way of inferring that something observed that something observed through a microscope, telescope, through a microscope, telescope, etc. is a physical object.etc. is a physical object.

– They are only color patches, They are only color patches, shadows, etc.shadows, etc.

Do you see a Do you see a subatomic particle?subatomic particle?

MaxwellMaxwell’’s rebuttals to s rebuttals to the unaided human the unaided human accountaccountE.E. Every observation is mediated Every observation is mediated

through something, so nothing through something, so nothing would be observable if this would be observable if this response were true.response were true.– The mediation objectionThe mediation objection

F.F. The argument from contemporary The argument from contemporary chemistry.chemistry.– Modern chemistry poses no strong Modern chemistry poses no strong

distinction between observable and distinction between observable and unobservable molecules.unobservable molecules.

The mediation The mediation objectionobjection

1.1. If the unaided human account is If the unaided human account is true, then we cantrue, then we can’’t legitimately t legitimately infer the existence of physical infer the existence of physical objects from observations objects from observations involving: involving:

– Any sensory aid whatsoever—Any sensory aid whatsoever—opera glasses, bifocals, etc.opera glasses, bifocals, etc.

– Any medium whatsoever—Any medium whatsoever—seeing through atmospheric seeing through atmospheric conditions, windowpanes, etc.conditions, windowpanes, etc.

2.2. These inferences are legitimate.These inferences are legitimate.3.3. So the unaided human account So the unaided human account

is false. is false.

Thus, there is no firm distinction

between theory and observation—we clearly need a

theory of optics to treat anything we see as a “direct

observation.” (1056)

Contemporary Contemporary chemistrychemistry

1.1. There is a continuous transition There is a continuous transition from small from small ““unobservableunobservable”” molecules such as hydrogen, to molecules such as hydrogen, to ““medium-sizedmedium-sized”” ones (proteins), to ones (proteins), to large, directly observable ones (salt large, directly observable ones (salt crystals).crystals).

2.2. Thus molecules are neither clearly Thus molecules are neither clearly observable nor clearly observable nor clearly unobservable entities.unobservable entities.

Hydrogen Hydrogen AtomAtom

ProteinProtein Salt CrystalSalt Crystal

RecapRecap

Antirealism requires a strong Antirealism requires a strong distinction between observable distinction between observable and unobservable entities.and unobservable entities.

Three of its best attempts—the Three of its best attempts—the sense-data, theory, and unaided sense-data, theory, and unaided human approaches—all face human approaches—all face serious objections.serious objections.