Science

1
Science Its Pretenders

• Cf. Reading List for core and suggested readings.

2
Topics

• The Amazing Power of Science A Very Brief
  Reflection
• Science Pseudoscience Poppers Demarcation
  Criterion
• Comments on Poppers Falsificationism
• Hypothesis Evidence
• Criteria of Adequacy
• Further Example Evolution vs. Creationism

3
The Amazing Power of Science A Very Brief
Reflection

• Influence every aspect of our lives tremendously.
• Change the world with an exceedingly fast pace.
• Produce scientific knowledge with astounding
  breath and depth.

4
Science Pseudoscience Poppers Demarcation
Criterion

• About 100 yrs ago, people were deeply interested
  in theories like
• Alfred Adlers (1870-1937) individual psychology
• An inborn sense of inferiority
• Strive for superiority
• Seemed to be able to explain everything within
  its field of inquiry!

5

• Albert Einsteins (1879-1955) theory of
  relativity
• Relativistic spacetime e.g. simultaneity is
  relative.
• E mc2
• One of the two pillars of modern physics.

6

• Both claimed to be scientific.
• Science signifies __________, ___________,
  ___________.
• Yet, Karl Popper (1902-1994) held that theories
  like Alders is actually not scientific.

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• He raised the demarcation problem
• When should a theory be ranked as scientific?
• Is there a criterion for the scientific status of
  a theory?

Scientific / Pseudoscientific
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• His criticism of theories like Adlers
• Adlers theory could easily explain two
  diametrically opposite cases, e.g.
• A man pushes a child into the water with the
  intention of drowning it.
• A man sacrifices his life in an attempt to save
  the child.
• How?
• By appealing to the idea of inferiority feeling,
  . . .

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• Its explanatory power is just a disguise of its
  interpreting power.
• Points for analysis in your paper, e.g. How is
  this interpreting power harmful to a theory?
  (Hint meaning shift of some key concepts)
• This apparent strength - capable of explaining
  everything - is in fact a weakness.

10

• Arthur Eddingtons confirmation (1919) of
  Einsteins theory was different
• The light-bending prediction
• Might be refuted not always confirmatory!

11

• Consequently, Popper proposed
• The criterion of the scientific status of a
  theory is its
• falsifiability,
• or refutability,
• or testability.
• Is this criterion adequate?

12
Comments on Poppers Falsificationism

• Two senses of falsifiability
• Falsifiability as a logical property of
  statements
• Falsifiable, e.g.
• It never rains on Wednesdays.
• All substances expand when heated.

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• Unfalsifiable, e.g.
• Luck is possible in sporting speculation.
• There is a ghost in this room which cannot be
  sensed, directly or indirectly.
• Falsifiability as a methodological prescription
  of how scientists should act
• E.g. try to make all substances expand when
  heated unfalsifiable in this sense.
• But both these senses are problematic!

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• 1. The logical sense
• Too _______
• Suppose T is a theory having testable
  predictions.
• Let C be, say, there is a ghost in this room
  which cannot be sensed, directly or indirectly.
• Then T C has testable predictions and thus
  scientific in the logical sense!

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• 2. The methodological sense
• Too ________
• E.g. the discovery of Neptune
• Newtons theory of gravitation wrongly predicted
  the orbit of Uranus abandoned it?
• In fact, some scientists tried to rescue Newtons
  theory by postulating the existence of an unknown
  planet.
• Neptune was finally discovered at almost the
  exact place and time as predicted.

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• The failure of Popper's criterion throws up an
  important question
• Is it possible to find some common features
  shared by all the sciences, but not shared by
  anything else?
• Has science essential features?
• Popper assumed that the answer was yes.

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• Ludwig Wittgenstein (1889-1951) argued against
  essentialism.
• Family resemblance concepts like game have no
  essential features.
• Cf. His Philosophical Investigations, sections
  66-7.

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GAMES

• A B C D E
  F
• 1 ------------- --------
  -------
• 2 ------------------------------
• 3 ------- -------
  -------
• 4 -----------------------
  --------------
• 5 -------------- ---------------
  

FEATURES
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• The same may be true of science.
• Note the heterogeneity of science.
• If so, no simple criterion for demarcating
  science from pseudoscience.
• How actually should we choose among hypotheses
  scientific or pseudoscientific?

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Hypothesis Evidence
 

• The logic of hypothesis testing

Main hypothesis ( background assumptions)
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• Discussion - a daily example
• The problem
• A lamp does not light up.
• Hypothesis
• Implication
• Test
• Result

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• Positive evidence does not prove conclusively
  that a hypothesis is correct.
• There are always competing hypotheses that have
  the same set of positive evidence.

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• Negative evidence does not prove conclusively
  that a hypothesis is incorrect.
• A Modus Tollens
• (Hypothesis H Assumptions A) ? Implication I
• ? I
  .
• ? (H A)
• So maybe the trouble comes from A.

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• Example
• Columbus and the negative evidence against the
  flat Earth hypothesis
• Supporting the round Earth hypothesis

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• Saving the flat Earth hypothesis
• Assumption light travels in curved lines.
• Facts alone cannot decide which hypothesis to
  accept.
• Criteria of Adequacy are needed.

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• Discussion
• What do you think are the criteria of adequacy?