Transcript Philosophers of science

Philosophy of science II
From positivists to Thomas Kuhn
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Key concepts in the philosophy of
science
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Positivism
Logical positivism
Falsificationism
Paradigms
Anarchy
Social constructions
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Positivism
Auguste Comte (1798-1857)
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Facts
Facts
More facts
Generalize from those
facts
• = induction
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Comtes evolutionary stages
Law of three phases of civilisation’s evolution
• Theological
• Metaphysical
• Scientific
The final positive stage
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Logical positivism
• Vienna circle 1920’s- 1930’s
– Moritz Schlick, Rudolf Carnap, Otto Neurath,
A. J. Ayer
• Metaphysics ( = not science):
– All propositions that are neither verifiable by
empirical observation nor demonstrable as
analytic.
– Ex.: religious and ethical statements....
• Scientific method
– Induction and verifiability
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Alfred Ayer (1910-89) in his Language,
Truth and Logic first published in 1936.
The first claim of logical positivists is that a statement can
only be true only if either
• it is a self-evident analytic, deductive truth of the kind
found in mathematics and formal logic (e.g. ‘2+2=4’)
or because
• the statement matches reality precisely. A consequence
of this was that statements had to be verifiable to be
meaningful.
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Vienna circle project
• Develop an exact and unbiased language for
science.
– logic, mathematics.
• Demarcation problem
– make a clear distinction between science and
metaphysics (not science)
• Reductionism:
– Physics, the queen of science.
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Falsificationism
• Karl R. Popper 19021994
• Criticized inductivism
and verifiability:
– No number of cases of
“A being B” can
establish that “all A
being B”. All such
statements remain
disprovable.
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Principle of falsifiabillity
• Scientific theory can never be accorded more than a
provisional acceptance.
• A theory holds until it is disproved.
• Falsification, not verification is the appropriate object of
the observational and experimental procedures of science.
• Falsifiability is a necessary part of a scientific theory.
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Popper’s
hypothetico-deductive method
• Enlargements of our temporary knowledge begins
with the conversions of hunches or imaginative
insights into hypotheses.
• Then, once the conditions for falsification have
been established by the application of deductive
logic, such hypotheses must be tested through
sustained search for negative instances.
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Assignment
• Try to give an examples of theories which are
falsifiable and not falsifiable.
• What would Popper say about a theory which is
not falsifiable?
• Are popperianism or/and logical positivism
descriptive or normative theories of science? Argue
for your answer.
• What does this have to do with the problem of
demarcation?
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Post-Popperian theories
• Both The logical positivists and popperians
did not describe reality, they were creating
norms about how they thought science
should be practiced for the best ( most
effective ) results.
• Critics by
– Thomas Kuhn, Imre Lakatos, Paul
Feyerabend…
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Thomas S. Kuhn (1922–96)
• “Structure of the scientific
revolution” (1962)
• Paradigm theory
– Prescience - normal science
- crisis - revolution - new
normal science - new crisisrevolution…
• A theory based on study of
history of science
• Attempts to describe how
science develops in reality
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Kuhn's normal science
• Grand theory as a paradigm
• Praxis
– community of scientists
• social power-relations and structures in the scientific
community
– methodological school, exemplars
– puzzling reality in terms of the grand theory by
deduction
– increasing anomalies lead to crisis
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Paradigm shift
• In crisis there will be ‘extraordinary science’
where there will be several competing
theories
• One theory will win because it will get the
greatest number of supporters in the scientific
community
• ‘Paradigm shift is an ‘irrational’ process, such
as accuracy, scope, simplicity, fruitfulness,
and the ‘like’ of each paradigm
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Kuhns wiew on scientific revolution
• Not (unexpected) new results from research,
rather a new perspective or interpretation of
data.
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Assignment
• Exemplify the following concepts:
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Paradigm
Normal-science
Exemplars
Anomalies
Paradigm in crisis
Extraordinary science
Paradigm shift
incommensurability
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Imre Lakatos
• ‘Criticism and the methodology
of scientific research programs’
(1968 )
• Reacts to Kuhn’s views and
claims that
– there does exist an objective criteria
where scientists can make a rational
choice between two competing
theories
– it is due to dishonesty that some
scientists do not give up their
position
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Lakatos’ scientific research
programs
• Research programs are series of theories
which can be viewed in two ways
– a. negative heuristic that states a ‘untouchable
hard core’ of hypothesis with a protective belt
around it, protecting it from falsification
– b. positive heuristic declaring that the core can
be altered slightly in order to fit progression
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Positive heuristic
• is the good one from Lakatos point of view
– The development from Copernicus to Newton
is his good example
• Negative heuristic is the less good one
– Tyco Brahes geocentric theory is Lakatos
example here
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The Lakatos view ?
• He revised the Popperian view after Kuhn
• If the Popperian view had been practiced
through history none of the progressive
theories would have survived
• He wanted to save the sciences from Kuhn's
irrational grounds
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Anarchy
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Paul Feyerabend
No single correct method in science
Anything that works is fine
= epistemological anarchy
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Social construction of science
• “laboratory life” is disorganized
• Scientific logic vs. availability of
equipment, funds, careers etc.
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