Structure of Scientific Revolutions, III

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Structure of Scientific Revolutions, III

• October 22, 2008

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Reminders

• Midterm Paper due 10/31
• Look over instructions.
• Look over sample.
• No more than 5 pages.
• Should include an argument in numbered form.

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SCIENTIFIC CRISIS AND THEORY CHANGE
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Crisis and Theory Change

• Weve seen paradigm normal science.
• Q How do these paradigms lead to their own
  destruction and necessitate change?
• Kuhn research under a paradigm must be a
  particularly effective way of inducing paradigm
  change. (52)

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Three examples

• AstronomyCrisis Ptolemaic system.Change Coper
  nican system.

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Ptolemaic System
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Copernican System
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From the preface to De Revolutionibus
I was impelled to consider a different system of
deducing the motions of the universe's spheres
for no other reason than the realization that
astronomers do not agree among themselves in
their investigations of this subjecttheir
experience was just like someone taking from
various places hands, feet, a head, and other
pieces, very well depicted, it may be, but not
for the representation of a single person since
these fragments would not belong to one another
at all, a monster rather than a man would be put
together from them.
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Three examples

• AstronomyCrisis Ptolemaic system.Change Coper
  nican system.
• CombustionCrisis Phlogiston theory.Change
  Lavoisiers oxygen theory.

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Phlogiston Theory
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Phlogiston Theory
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Problems with Phlogiston
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Three examples

• AstronomyCrisis Ptolemaic system.Change Coper
  nican system.
• CombustionCrisis Phlogiston theory.Change
  Lavoisiers oxygen theory.
• SpacetimeCrisis Ether theory.Change Einstein
  s theory of relativity.

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A Kuhnian Argument

• 1. Crisis is necessary for novel theories.
• 2. Paradigm normal science is necessary for
  crisis.------------------------------------------
  ---------
• 3. Thus, paradigm normal science is necessary
  for novel theories.

In other words, it is a good thing that there is
paradigm science. (e.g., Kuhn, p. 61)
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Kuhn and Confirmation

• No reason to change theories until crisis.
• This is a good thing.
• So, a theory can be rationally held onto just by
  being accepted, even if there are other competing
  theories.

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Kuhns Claim

• The paradigms are necessary for this kind of
  crisis and then change.
• Evidence these revolutionary theories were
  proposed in times of non-crisis, but not accepted.

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RESPONSE TO CRISIS
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Kuhns Ch. 8 Claim
Scientists do not reject a theory in response to
counter-instances.
Why not? Kuhn has two main reasons.
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Scientists do not reject a theory in response to
counter-instances

• 1. Scientists dont reject theory until there is
  an alternative.
• the act of judgment that leads scientists to
  reject a previously accepted theory is always
  based upon more than a comparison of that theory
  with the world. (77)

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Picture 1

• Consider Ptolemaic Astronomy (PA).
• If PA is true, then the moon should have been at
  such-and-such location last night (O). But it
  wasnt. So, we reject PA.

Counter-instance O is reason to reject PA.
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Picture 2

• Consider PA and Copernican Astronomy (CA).
• If PA is true, then the moon should have been at
  such-and-such location last night (O). But it
  wasnt. This is a puzzle.
• But according to CA, the moon should have been
  where it actually was. So, we reject PA and
  accept CA.

Counter-instance O is reason to reject PA,
relative to CA.
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Scientists do not reject a theory in response to
counter-instances

• 1. Scientists dont reject theory until there is
  an alternative.
• Picture 2 is correctO alone does not lead us to
  reject PA. Only with the alternative CA can it do
  this.

Kuhn what one scientist sees as a
counter-instance, the other sees as a puzzle.
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Kuhns Claim
There are, I think, only two alternatives
either no scientific theory ever confronts a
counterinstance, or all such theories confront
counterinstances at all times. (80) If this is
true, then counterinstances dont determine
rejection and accepting of scientific theories.
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Scientists do not reject a theory in response to
counter-instances

• 1. Scientists dont reject theory until there is
  an alternative.
• 2. Analogy with epistemology/philosophy of
  science.

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Analogy Argument

• Epistemological Theory 1 counter-instances
  should lead to theory rejection.
• Counterexample counter-instances that do not
  refute theories.
• Epistemological Theory 2 theories should be
  taken equally seriously if consistent with same
  data.
• Counterexample theories not taken seriously
  until crisis of accepted theory.

Kuhn Until there is an alternative philosophy of
science, you philosophers will keep modifying
your theories and adding ad hoc fixes to avoid
these counterexamples, thus not letting them
refute your theory.
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Analogy Argument

• Epistemological Theory 1 counter-instances
  should lead to theory rejection.
• Counterexample counter-instances that do not
  refute theories.
• Epistemological Theory 2 theories should be
  taken equally seriously if consistent with same
  data.
• Counterexample theories not taken seriously
  until crisis of accepted theory.

Kuhns Response Look, youre accusing
scientists of being irrational by not dropping
theories in the face of apparent counterexamples.
But you look to be doing the same thing making
up ad hoc distinctions and holding onto the
theoryis it really so irrational?
ONE RESPONSE these examples are about how people
do act, but the theories are about how people
should act. So there is no conflict.
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The Structure of Scientific Revolutions, IV

• October 24, 2008

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Theory Change

• Kuhns important point Not every conflict of
  the theory with data leads to theory-rejection.
  Nor should it.
• But then a question When does conflict lead to
  theory- rejection? When should it?

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Theory Change

• But then a question When does conflict lead to
  theory- rejection? When should it?
• Kuhns apparent answer - When the conflict has
  become a crisis. - When we are in possession of
  an alternative theory.

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Theory Change

• 1. Not all conflicts provoke crisis.
• 2. What makes a conflict provoke a crisis is due
  to social aspects of science, non-observational
  facts.
• 3. Crisis is what provokes scientific change
• --------------------------------------------------
  ------
• 4. Thus, when science changes, it is due to
  social/non-observational facts.

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Theory Change

• 1. Not all conflicts provoke crisis.
• 2. What makes a conflict provoke a crisis is due
  to social aspects of science, non-observational
  facts.
• 3. Crisis is what provokes scientific change
• --------------------------------------------------
  ------
• 4. Thus, when science changes, it is due to
  social/non-observational facts.

Why? this is what we established last time
concerning counter-instances and puzzles.
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Theory Change

• 1. Not all conflicts provoke crisis.
• 2. What makes a conflict provoke a crisis is due
  to social aspects of science, non-observational
  facts.
• 3. Crisis is what provokes scientific change
• --------------------------------------------------
  ------
• 4. Thus, when science changes, it is due to
  social/ non-observational facts.

Why? p. 82. Lack of problem-solving ability plays
some role in crisis, but not complete role.
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Theory Change

• 1. Not all conflicts provoke crisis.
• 2. What makes a conflict provoke a crisis is due
  to social aspects of science, non-observational
  facts.
• 3. Crisis is what provokes scientific change
• --------------------------------------------------
  ------
• 4. Thus, when science changes, it is due to
  social/ non-observational facts.

Why? This is what Kuhn establishes in ch. VII.
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Theory Change

• 1. Not all conflicts provoke crisis.
• 2. What makes a conflict provoke a crisis is due
  to social aspects of science, non-observational
  facts.
• 3. Crisis is what provokes scientific change
• --------------------------------------------------
  ------
• 4. Thus, when science changes, it is due to
  social/ non-observational facts.

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Against Cumulativity

• The transition from a paradigm in crisis to a
  new one from which a new tradition of normal
  science can emerge is far from a cumulative
  process, one achieved by an articulation or
  extension of the old paradigm. Rather it is a
  reconstruction of the field from new
  fundamentals, a reconstruction that changes some
  of the fields most elementary theoretical
  generalizations as well as many of its paradigm
  methods and applications. (84-85)

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Against Cumulativity

• This should sound odd. Isnt science cumulative?
  Dont we learn more and more?

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Against Cumulativity Examples

• Some problems no longer require solution, either
  because they make no sense in the new paradigm,
  or they are simply rejected.
• Dalton.
• Ether.
• Some new entities are introduced along with the
  paradigm indeed, only make sense (i.e., can be
  conceptualized) when introduced as such.
• Oxygen.

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Against Cumulativity Examples

• Standards for evaluating scientific theories
  alter along with the problems that a theory must
  (according to the paradigm) solve.
• Newton and occult forces.
• Elements that are preserved may have an entirely
  different status.
• Speed of light.
• Newtons Second Law.

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Kuhns Analogy

• There is no cumulative scientific progress,
  because across paradigms, the facts, problems,
  and standards are different.

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Kuhns Analogy

• Ex You dont see things more completely when you
  see the duck/rabbit, or the random
  patterns/Dalmatian, you just see differently.
  There is no progress.
• The change is not brought on by evidence but is a
  conversion.

Scientific Change - Not solely determined by
evidence, but social/non- observational
facts. - Analogous to a religious conversion.
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Kuhns Analogy

• But
• We can switch back-and-forth. Scientists cannot.
• The parallel can be misleading. Scientists do
  not see something as something else instead,
  they simply see it.(85)

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Summary

• Two pictures of science, neither the standard
  pre-Kuhn pictures
• Normal Science
• Close-mindedDogmatic
• Revolutionary science
• Prompted by non-scientific things
• No cumulative gain in knowledge
• Like a conversion experience