Sir Karl Popper, part II

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Sir Karl Popper, part II

• October 14, 2008

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Statements of Science

• Statements of science justified dogmatically.
• OR
• Justification results in a regress.

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The Trilemma

• Regress
• OR
• Dogmatism
• OR
• Psychologism

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The Trilemma

• Regress all statements need a justifier
• Dogmatism basic statements are justified on
  their own
• Psychologism experiences justify basic
  statements

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Popper against Psychologism
1. Observations cannot verify any statement.
Example Here is a glass of water. Here is
an object which has certain universal lawlike
properties that contains a kind of substance that
has different universal lawlike
properties. Experience alone doesnt verify
that.
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Popper against Psychologism
2. The problem from last time about sense
experience.
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Popper against Psychologism
Admittedly it is not incorrect to say that
science is an instrument whose purpose is to
predict from immediate or given experiences later
experiences, and even as far as possible to
control them. But I do not think that this talk
about experiences contributes to clarity. It has
hardly more point than, say, the not incorrect
characterization of an oil derrick by the
assertion that its purpose is to give us certain
experiences not oil, but rather the sight and
smell of oil not money, but rather the feeling
of having money. (115)
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Why is Popper Against Psychologism?

• I propose to look at science in a way which is
  slightly different from the way favoured by the
  various psychologistic schools I wish to
  distinguish sharply between objective science on
  the one hand, and our knowledge on the other.
  (113)

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The Trilemma

• Regress all statements need a justifier
• Dogmatism basic statements are just justified
  on their own
• Psychologism certain experiences justify basic
  statements

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If not Psychologism, then what?

• We decide to stop at easily observable basic
  statements. But nothing compels us to do this.
• Q What are easily observable basic statements?

Statements about personal sense-experience are
not basic statements. Such statements are not
easily observable by the scientific community.
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If not Psychologism, then what?

• For any basic statement can again in its turn be
  subjected to tests, using as a touchstone any of
  the basic statements which can be deduced from it
  with the help of some theory, either the one
  under test or another. This procedure has no
  natural end. Thus if the test is to lead us
  anywhere, nothing remains but to stop at some
  point or other and say that we are satisfied, for
  the time being. (p. 117)

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Response to the Trilemma?

• Dogmatism
• sort of.
• We decide what statements are basic and this
  justifies them.
• But we could always question these basic
  statements, so there is no absolute dogmatism.
• In support
• If we didnt agree on basic statements, science
  would be chaos.
• Scientists do (usually) agree on basic
  statements.
• Nothing could possibly force someone to accept a
  basic statement, so dont build that into your
  theory.

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Response to the Trilemma?

• Q What do we think about this view?
• Q If we simply decide whether or not to accept
  basic statements, why cant we decide whether or
  not to accept theories?

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Tension

• I admit, again, that the decision to accept a
  basic statement, and to be satisfied with it, is
  causally connected with our experiences
  especially our perceptual experiences. But we do
  not attempt to justify basic statements by these
  experiences. (118)

What Popper seems to need is some notion of
support and not just falsification.
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Falsification Worries

• Theory The chance of heads is ½.
• Q Do any observations deductively refute this
  theory?
• Q If not, then what should Popper say about
  this?
• Example Mendels Peas.

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General Moral

• Popper is pressured on many sides to embrace some
  sort of confirmation
• 1. for probabilistic theories (which cant be
  falsified) and
• 2. for observations (to get some sort of
  objectivity).