Van Fraassen

1
Van Fraassens Critique of Scientific Realism

• Kareem Khalifa
• Department of Philosophy
• Middlebury College

2
Overview

1. Defining Scientific Realism
2. Constructive Empiricism
3. Defending the Theory-Observation Dichotomy
4. Critiquing Inference to the Best Explanation (IBE)

3
I. Defining Scientific Realism

1. What realism is not
2. Realism defined

4
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).
5
Differences between the two antirealisms

• Option 1 (non-literal construals of theories)
  the quark theory doesnt 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
  didnt exist.

6
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.

7
Empirical Adequacy vs. Truth

• The quark model would be false but empirically
  adequate if quarks didnt exist but everything it
  said about observable things and events is true.
• Saving the phenomena (1069)
• Applies to future observations, unobserved but
  observable entitiesin short, an empirically
  adequate theory must save all phenomena.

8
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

9
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.

10
III. BvF the Theory-Observation Dichotomy

• Van Fraassen replies to two potential objections
  to CE
• Mediation Objection If electron microscopes
  dont yield direct observation, then neither does
  anything else.
• Mutation Objection Unobservability in
  principle Observability under different
  circumstances

11
A. BvFs 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.

12
B. Maxwells 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.

13
BvFs 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.

14
IV. Inference to the Best Explanation (IBE)

• Reminders
• The Ordinary Practice Argument
• Smarts First Argument
• Smarts Second Argument
• Sellars Thought Experiment
• The Ultimate/No Miracle Argument

15
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.

16
B. The Ordinary Practice Argument(1076-1077)
17
BvFs Rebuttal to the Ordinary Practice Argument

• we are always willing to believe that the theory
  which best explains the evidence, is empirically
  adequate. (1076)

18
C. Smarts First Argument (1077-1078)
19
BvFs Reply to Smarts 1st Argument
20
D. Smarts 2nd Argument (1078-1079)
21
BvFs Reply to Smarts 2nd Argument
22
E. Sellars Thought Experiment (1079-1082)
23
BvF vs. Sellars
24
F. The Ultimate/Miracle Argument(1082-1084)

• Theories are empirically adequate.
• The truth of theories best explains their
  empirical adequacy.
• Therefore, theories are true.

25
Van Fraassens Rebuttal to the Miracle Argument
26
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.