Lecture 5 Kuhn

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Lecture 5Kuhn
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Some biographical facts

• Born in 1922.
• Entered Harvard in 1939 (studied physics).
• Received a Ph. D. in physics in 1949.
• Moved to Berkeley in 1957.
• Moved to Princeton in 1964.
• Moved to MIT in 1983.
• Retired in 1991
• Main works
• The Copernican Revolution, 1957
• The Structure of Scientific Revolutions,
  1962
• The Essential Tension, 1977
• Died in 1996.

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The Structure of Scientific Revolutions

• The most quoted book in humanities.
• Marked the end of logical positivism (although it
  was published in the Encyclopedia of Unified
  Science!)
• Made philosophy of science more interested in
  history of science.
• Started the propulsive field of social studies
  of science.
• Inspired anti-science attitudes and social
  constructivism.
• Influenced the popular culture by introducing the
  trendy expressions paradigm and paradigm
  shift.
• And it all actually started with Kuhn teaching a
  general education course at Harvard!

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Normal science

• According to Kuhn, science is usually
  characterized by what he calls puzzle-solving.
• There is a considerable consensus (agreement)
  among scientists about fundamental things, which
  are never put into question.
• The task is always to work on small, precisely
  defined problems that are to be solved by using
  methods that worked in similar situations in the
  past.
• Scientists dont ask big questions and dont even
  think about the possibility that some of the
  basic assumptions of their discipline might be
  false.
• They are trained (Kuhn sometimes says
  indoctrinated) to focus on questions that can
  be solved with current methods.
• Not finding a solution is blamed on a scientist,
  not science.

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Paradigm

• The word paradigm made Kuhns book famous.
• One critic listed 21 different meanings of that
  word in the Structure. What is a paradigm?
• Two things, basically. First, paradigm is all
  that theoretical background knowledge that is
  implicitly accepted by competent scientists in a
  given field.
• It is contained in textbooks or big books that
  one has to study and absorb, in order to be
  recognized as an expert. It is similar to
  Lakatoss hard core.
• Second, paradigm refers to standard examples
  and ways of solving problems. By going through
  these standard (textbook) examples one gets the
  practice and skills to attack similar problems
  and so to solve new puzzles.
• Becoming a scientist reduces to being exposed to
  many such examples, and applying the method to
  new situations.

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Paradigm (2)

• No paradigm is completely successful in solving
  all existing problems. Problems that stay
  unsolved for a long time are called anomalies.
• During the normal science period no one worries
  much about anomalies. The reason is that the idea
  of their approach being fundamentally wrong does
  not enter the scientists mind at all.
• There is an expectation that anomalies will be
  solved in some way later, or that they will
  perhaps be shown to be pseudo-problems, based on
  some misunderstanding.
• If anomalies accumulate and puzzle-solving fails
  in many cases, this can produce a crisis.
• Scientists may start looking for an alternative
  general perspective (paradigm).

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Revolutionary science

• A crisis can lead to the emergence of a new
  paradigm, and if the new paradigm wins,
  paradigm-shift will happen.
• Ptolemaic-Copernican, phlogiston-Lavoisier,
  Newton-Einstein, classical physics quantum
  physics.
• Scientific revolutions are similar to political
  revolutions. In the period of normal politics
  changes are continuous, and introduced with the
  help of assumptions that are agreed upon by all
  and never questioned. Revolutions are
  discontinuous and represent a break, fundamental
  change, sometimes a complete failure of
  communication between the opposing parties.
• Disagreements cannot be resolved by relying on
  common political standards. Force is used, not
  the negotiation.

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Paradigm shift

• The clash of paradigms in science is also
  characterized by the break of communication.
• The perspectives of rival paradigms are so
  fundamentally different that Kuhn sometimes said
  that scientists belonging to different paradigms
  actually live in different worlds.
• This is the part that led to radical
  interpretations of Kuhn in the spirit of social
  constructivism, which he disavowed.
• In more guarded moments, he says that basic
  concepts in rival paradigms have different
  meanings.
• They speak different languages, or as he used to
  say, the rival theories are incommensurable (the
  term he shares with Feyerabend)
• Incommensurable means cannot be compared by a
  common measure. (The term comes from
  mathematics.)

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Incommensurable numbers
If the length of the side of the big (red) square
is a, and the side of the small square is b,
Pythagoras proved that a and b are
incommensurable they are not measurable by the
same measure.
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Paradigm shift (2)

• One thing giving rise to incommensurability is
  the difference in meaning. The languages are so
  different that they cannot be translated into one
  another.
• An additional problem is that a paradigm shift
  involves not only belief-change but also the
  change in standards of judgment (what makes
  science good or bad).
• If two camps use different standards to decide
  what is good or bad science, and if (as Kuhn
  believes) there is no external, paradigm-neutral
  standpoint to resolve this disagreement, then
  there is no objective method to decide who is
  right.
• The change of paradigm is not the result of
  argumentation or rational persuasion, but more
  like a change of perspective that cannot be
  explained as happening for a reason. It resembles
  a gestalt switch in perception.

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Duck or rabbit?
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Girl or old woman?
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Is observation the solution?

• The natural suggestion is to have observation
  resolve the conflict. Seeing is believing.
• But Kuhn claims that observation is
  theory-laden or infected with theory.
• There are no pure observation sentences. What we
  observe always depends on which theories we
  accept. Therefore, the idea that observation
  could be a neutral judge of theories is naïve and
  unacceptable.
• For example, although we see with our own eyes
  that sun is moving across the horizon,
  Copernicans managed to reinterpret this
  observation as a false belief imposed on us by
  wrong theory.

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Remember this card!
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Progress?

• Kuhn does not think that there is scientific
  progress in the sense that science moves closer
  and closer to the truth.
• He believes that there is no perspective-independe
  nt measure of how much truth different theories
  contain.
• He once called himself a Kantian with movable
  categories.
• Kant the categories of our mind are a
  precondition for any understanding or knowledge.
  We misattribute the necessity to the world, when
  it really comes from our subjectivity.
• Kuhn applies the same idea, with the difference
  that categories change during scientific
  revolutions.
• Some critics complained that Kuhn makes
  scientific change completely irrational, like a
  mass conversion.

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Summary

• The first stage in the development of a field is
  pre-paradigmatic. Research is not mature yet.
  There are constant debates about fundamental
  questions, no minimal consensus about methods,
  fruitful topics, or important results.
• In the second stage, one of the standpoints wins
  the upper hand, and gets established as the
  dominant opinion. The paradigm is born. Normal
  science begins.
• In the third stage (crisis), anomalies
  accumulate, the trust in the paradigm is
  weakened.
• In the fourth, stage, alternatives appear and one
  of them replaces the old paradigm (revolution).
• In the fifth stage, normal science (under the new
  paradigm) starts its long life.

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