PS2080 - Making theoretical Progress


Deduction v Induction

Deductive Reasoning

- top down

- more narrow

- concerned with hypothesis testing

- theory - hypothesis - observation - confirmation

Inductive Reasoning

- bottom up

- open-ended

- more exploratory

- observation - pattern - tentative hypothesis - theory

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Problems with verification

- induction Problem

- what about unobservable facts?

- our observations may be wrong

- our observations are not objective

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Popper (1902 - 1994)

- austrian born scholar

- member of the vienna circle

- professor at the london school of economics

- popper's initial interest was psychology

- falsification instead of verification

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Falsification instead of verification


- science constantly questions its explanations

- falsification - disproving a theory or hypothesis

- a scientific statement is one that could possibly be proven wrong

- falsifiability - criterion for demarcating sceince form non-science

- hypothetico - deductive method: observation - interpretation - hypothesis - test - observation etc

hypothesis should be directed at a possible falsification

Degrees of falsification: the more falsifiable a theory, the higher its scientific status

the more specific a statement, teh more proe to falsification, the higher the scientific status

e.g. wine sours because of organisms v wine sours because of bacteria coming from the air

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Criteria for choosing theories

- Scope: a good theory makes wide-ranging claims about the world

- Precision: the more precise a theory the more falsifiable it is

- Parsimony: among competing theories, the one that makes the fewest assumptions should be favoured

- Increasing falsifiability: the more falsifiable a theory the better. Theories should become more and more falsifiable: more content + more informative - a replacement theory should be more falsifiable than that which is replaced

- Fruitfulness: has the theory led to new empirical discoveries? does the theory lead to scientific progress? falsifying theories and offering more precise and falsifiable replacements leads to new discoveries

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ad hoc modifications

ad hoc modification = changes to a theory that makes the theory less falsifiable

What are allowable and unallowable modifications?

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Thomas Kuhn 1922 - 1996

- american physicist

- the structure of scientific revolutions

- science is a social activity

- scientifc paradigm - set of common views of what the discipline is about and how problems should be investigated

Kuhn's theory of scientific progress:

pre-science - normal science - crisis - revolution - new normal science - new crisis etc

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Kuhn: a paradigm determines

A paradigm determines:

what is to be observed and scrutinized

- what kinds of questions should be asked

- how the questions are to be structured

- how the results of scientific investigations should be interpreted

- how an experiment is to be conducted

- what equipment will be used

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Kuhn: structure of scientifc revolution

Pre-science: unorganised facts, observations and models to explain small scale phenomena

Normal science: researchers share paradigms. attempts made to falsify the theory. modification can be made

Revolution: confidence in paradigm decreases, crisis, scientific revolution and paradigm shift

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Implication of Kuhn's theory

- paradigms are ever changing

- revolution = progress?

- knowledge = relative and time dependent

- scientists engage in 'puzzle solving'

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Kuhn v Popper

  • Kuhn - normal science = important, Popper = noraml science does exist but does not = good science
  • Kuhn - scientists should criticise occasionally, Popper - scientific approach = criticial attitude
  • Kuhn - hypercriticial scientists don't get any work done + conformity and focused puzzle-solving are essential, Popper - criticism and non-conformity are essential
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Middle ground of Kuhn and Popper

Objective component, grounded in reality,  constant coupling of ideas to observations by using verification and falsification in a guarantee that the ideas will not be completely in contradiction with the reality as it can be observed

Science proceeds by trial and error and happens within a paradigm - people should always be criticial of scientific claims

rule of thumb: look at converging evidence

long series of different falsifcation attempts

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