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Philosophy of science II

From positivists to Thomas Kuhn

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Key concepts in the philosophy of science

• Positivism

• Logical positivism

• Falsificationism

• Paradigms

• Anarchy

• Social constructions

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Positivism Auguste Comte (1798-1857)

• 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 1902-1994

• 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 crisis- revolution…

• 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:– 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

• 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.