Van Fraassen’s Critique of
Scientific Realism
Kareem Khalifa
Department of Philosophy
Middlebury College
Overview
I. Defining Scientific Realism
II. Constructive Empiricism
III. Defending the Theory-Observation
‘Dichotomy’
IV. Critiquing Inference to the Best
Explanation (IBE)
I. Defining Scientific Realism
A. What realism is not
B. Realism defined
II. Constructive Empiricism
•
Two (overlapping) possibilities:
– Science aims to be true, but only once
properly (but not literally) construed.
– The language of science should be literally
construed, but its theories need not be true
to be good.
I choose the second option,
and dub it CONSTRUCTIVE
EMPIRICISM (CE).
Differences between the two
antirealisms
• Option 1 (non-literal construals of
theories): the quark theory doesn’t really
say that quarks exist.
– Rather statements like “Quarks exist” are
useful fictions for theory construction,
instruments for organizing data and prediction,
etc.
• CE: the quark theory says that quarks
exist, but it would still be a good theory
even if quarks didn’t exist.
Constructive Empiricism
• Science aims to give us theories which are
empirically adequate; and acceptance of
a theory involves as belief only that it is
empirically adequate. (1069)
• Contrast with realism: Science aims to
give us, in its theories, a literally true
story of what the world is like; and
acceptance of a scientific theory involves
the belief that it is true.
Empirical Adequacy vs. Truth
• The quark model would be false but
empirically adequate if quarks didn’t exist
but everything it said about observable
things and events is true.
– “Saving the phenomena” (1069)
• Applies to future observations, unobserved
but observable entities—in short, an
empirically adequate theory must save all
phenomena.
Acceptance, commitment, and
belief (1069-1070)
• Acceptance = pro-attitude toward a
theory, consists of:
– Belief = pro-attitude that statements in
the theory are true;
– Commitment = pro-attitude to “confront
any future phenomena by means of the
conceptual resources of the theory”
(1069); more pragmatic than belief
How this bears on realism and CE
• Both realism and CE demand that acceptance
entails the belief that a theory is empirically
adequate
• But realism also demands belief that the theory
is true
– This accounts for the value of explaining phenomena
by appeal to unobservables.
• In place of this, CE claims that acceptance
involves commitment.
– As a result, the value of explanation is mostly
pragmatic.
III. BvF & the Theory-Observation
Dichotomy
Van Fraassen replies to two
potential objections to CE:
A. Mediation Objection: If
electron microscopes
don’t yield direct
observation, then neither
does anything else.
B. Mutation Objection:
“Unobservability in
principle” = “Observability
under different
circumstances”
A. BvF’s reply to the Mediation
Objection
•
•
•
•
•
“Granted that we cannot answer this question
[about how to classify observable and
unobservable things] without arbitrariness, what
follows? That ‘observable’ is a vague predicate.’
(1073)
There are no problems with vague predicates so
long as there are clear cases of ‘observables’ and
clear cases of ‘unobservables.’
A clear case of an observable is anything seen with
the unaided eye
A clear case of an unobservable is a subatomic
particle in a cloud chamber
So the concept of unobservability, and hence
antirealism, is intelligible.
B. Maxwell’s
“Mutation Objection”
• The theory approach to
unobservability: A theoretical entity
is unobservable in principle if the
theory positing it entails that it is
unobservable.
• Maxwell: If we had different
perceptual capacities, any entity
that is unobservable in this sense
can be made observable. So there
is no difference between
“unobservable in principle” and
“observable under different
conditions than our own.”
BvF’s reply to the Mutation
Objection (1074-1075)
• This is just punning on any concept
involving “-able,” i.e., dealing with
possibility.
– Ex. Is the Empire State Building “portable”
because future architects could be much
more ingenious than we are?
• The proper frame of reference is with
respect to what is observable by us, our
limitations as human beings.
IV. Inference to the Best
Explanation (IBE)
A. Reminders
B. The Ordinary Practice
Argument
C. Smart’s First Argument
D. Smart’s Second Argument
E. Sellars’ Thought
Experiment
F. The Ultimate/No Miracle
Argument
A. What is IBE?
• A pattern of reasoning of the following form:
–P
– Q best explains P.
– Therefore Q.
• Example:
– I hear scratching in the wall; my cheese disappears.
– The best explanation of the scratching and the
missing cheese is that a mouse is in the house.
– Therefore a mouse is in the house.
B. The Ordinary Practice Argument
(1076-1077)
BvF’s Rebuttal to the Ordinary
Practice Argument
“we are always willing
to believe that the
theory which best
explains the evidence,
is empirically
adequate.” (1076)
C. Smart’s First Argument
(1077-1078)
BvF’s Reply to Smart’s 1st Argument
D. Smart’s 2nd Argument (1078-1079)
BvF’s Reply to Smart’s 2nd Argument
E. Sellars’ Thought Experiment
(1079-1082)
BvF vs. Sellars
F. The Ultimate/Miracle Argument
(1082-1084)
• Theories are empirically adequate.
• The truth of theories best explains their
empirical adequacy.
• Therefore, theories are true.
Van Fraassen’s Rebuttal to the
Miracle Argument
Recap
• Scientific realism is the view that scientific theories
aim for truth, and acceptance involves the belief that
it is true.
• Constructive empiricism is the view that theories aim
for empirical adequacy, and acceptance involves
belief in empirical adequacy + commitment
• There are two kinds of argument for scientific
realism:
– The critique of the theory-observation distinction
– The use of IBE
• Each argument for scientific realism can be
challenged.