The development of science

1. The development of science Matthias Hoeh, Imperial College London, November 2005

2. The development of science The science of science Introduction Popper Kuhn Feyerabend Summary How does science “work”? This is a big questions first tried to answer in the 20th century! George Alfred Leon Sarton (1884-1956) is considered the founder of this discipline. The topic gained greater attention after World War II. Introduction Popper Kuhn Feyerabend Summary Today, there are 3 major models of the development of science.

3. Sir Karl Popper(1902 – 1994) The development of science Popper’s model of positivism Popper states: Progress is achieved through falsification of incorrect theories. The upcoming theory will then be nearer to the truth.  science as linear process, an accumulation of knowledge Introduction Popper Kuhn Feyerabend Summary The more recent theory contains the older one

4. Thomas Kuhn(1922 – 1996) The development of science Model of scientific revolutions The progess of science is not linear, but revolutionary. Old and new theories are incompatible. Introduction Popper Kuhn Feyerabend Summary This is the relevant concept today. First introduced 1962 in Kuhn’s book “the structure of scientific revolutions”

5. The development of science Introduction to Kuhn’s model A scientific community is defined by its common beliefs. Theories, methods, and standards their members have in common are called paradigm. normal science: scientific community claims to know how the world is like. An anomaly can undermine the existing tradition of scientific practice. Then, a scientific revolution can take place: a shift in professional assumptions (e.g. Copernicus revolution). A scientific revolution is a paradigm shift. Scientists will always try to resist such a change. New and old paradigm are incompatible. You can’t compare them (incommensurate). Introduction Popper Kuhn Feyerabend Summary

6. The development of science What is “normal science”? Normal science is based on past scientific achievements (paradigms) Normal science is puzzle-solving! To become a member of a scientific community students have to study its paradigm Normal science consists in • extending knowledge about facts that the paradigm describes. • increasing the consistency between nature and the predictions • further articulation of the paradigm itself to extend its application and accuracy Normal science brings all the well known problems: • determination of significant fact • matching of fact with theory • articulation and specification of the theory If there is a research, there is always an aim. No one will be just looking around. Unexpected results are first considered a failure or will often not be published. Of course, science does produce unexpected results! Introduction Popper Kuhn Feyerabend Summary

7. The development of science Paradigms for normal science The rules of normal science are always derived from one paradigm. There is no science without a paradigm. The scientist can disagree on the interpretation of the paradigm. Introduction Popper Kuhn Feyerabend Summary

8. The development of science Encountering anomalies If normal science is successful it produces no new theories and facts. Anyhow unsuspected phenomena come up and need to be dealt with. One possible aftermath: anomaly  discovery  …  paradigm-shift Introduction Popper Kuhn Feyerabend Summary

9. The development of science Opposing anomalies Novelties are always opposed by manifested expectations. Normal science first tries to suppress novelties. Introduction Popper Kuhn Feyerabend Summary Example 1: the Michelson-Morley-Experiment Example 2: Playing card experiment what card is being shown?

10. The development of science Crises in normal science First, if the puzzle is not solved, it discredits only the scientist and not the theory. But a continuously resisting anomaly can indicate a failure in an existing theory. That can lead to a crisis! • Invention of new theories boosts Introduction Popper Kuhn Feyerabend Summary

11. The development of science Crises in normal science Example: The Ptolemaic system of sun, stars and planets Old system: Introduction Popper Kuhn Feyerabend Summary Copernicus’ idea was not yet necessary New system (with epicycles) Generally more than one construction can be placed over a given collection of data Once a paradigm has established, others are strongly resisted. Only another crisis gives the opportunity to rethink.

12. The development of science Extraordinary science… …a response to a crisis! Theory and paradigm-testing period. Crisis loosens rules and theoretical stereotypes. Indicates important data for fundamental new theories. Introduction Popper Kuhn Feyerabend Summary 3 ways to close a crisis: • Normal science finally solves the puzzle and returns to normal research. • The problem is set aside due to a lack of necessary tool for further investigation. A new candidate for paradigm emerges, and a battle over its acceptance ensues. A new candidate for paradigm emerges, and a battle over its acceptance ensues. …transition to a new paradigm “picking up the other end of the stick” “scientists do not see something as something else; instead, they simply see it”

13. The development of science Scientific Revolutions Normal research is cumulative, scientific revolutions are not! New paradigm is incompatible with the old one  different predictions (old problems are assigned to other sciences or declared unscientific) Normal science can have only 1 paradigm at a time. No paradigm = no science! Introduction Popper Kuhn Feyerabend Summary

14. The development of science How to chose a paradigm Each community uses its own paradigmatic language for its defence. • Evaluation of paradigms impossible! • Choice is made by logic and persuasive argumentation • Aesthetic reasons, like simplicity and elegance, influence the choice The question is not whether or not a theory fits, but which one fits better. The important idea of a new paradigm is often brought by newcomers! Introduction Popper Kuhn Feyerabend Summary Why does a shift in view occur? Because the existing paradigm fails to fit!

15. The development of science The invisibility of revolutions The support for a new paradigm has to grow. Competent supporters will upgrade the paradigm. It is a long process, until the resistance of the old tradition supporters fades. Once a new theory is accepted the old ones tend to simply disappear. Example: In Textbooks revolutions are not indicated, although books have to be rewritten Introduction Popper Kuhn Feyerabend Summary "A science that hesitates to forget its founders is lost". (A.Whitehead)

16. The development of science Where is the progress? Linear progress takes place during normal science. Introduction Popper Kuhn Feyerabend Summary …until the paradigm fails! Then a scientific revolution (non-linear) is necessary to make another period of progress in a new paradigm possible. “truth” is not the ultimate criterion for science.  Paradigm changes don’t bring scientist closer and closer to the truth. Process of science is not going towards something. Example: evolution of organisms, which proceeds without a special goal!

17. The structure of scientific revolutions Nature New theories to conserve the old paradigm Experiment Theory Anomaly Discovery Crisis Adjusted theory Extraordinary science Normal science Theories on the basis of a certain Paradigm Paradigm shift / scientific revolution No solution (due to lack of ideas or possibilities for further investigation. Problem is set aside) New paradigms The development of science Overview of Kuhn’s model Introduction Popper Kuhn Feyerabend Summary

18. The development of science Relevance today Kuhn’s model is the most accepted concept about the development of science. Nevertheless it was extensively criticised and it still is. Some people blamed him for divorcing science from truth. Introduction Popper Kuhn Feyerabend Summary

19. Paul Feyerabend(1924 – 1994) The development of science Feyerabend’s opposing model Paul Feyerabend, Pluralistic philosopher and former physicist, went further than Kuhn did. He developed one of the major opposing models, which is much more radical. Introduction Popper Kuhn Feyerabend Summary New theories have little to do with previous theories. They are incoherent and inconsistent.

20. The development of science Against method Feyerabend is against falsification - it would enable any theory to rise, even if it brings many unsolved problems. Lack of consistent methodologies makes it impossible to label inquiries “scientific” or “non-scientific”. Suggestion: pluralistic methodology for the investigation of knowledge. Many forms of knowledge which were formerly considered as “non-scientific” were later accepted. Introduction Popper Kuhn Feyerabend Summary

21. The development of science Today’s view on science Many theories have been published in the decades after Kuhn’s. They can be classified somewhere in between the 3 presented models. Introduction Popper Kuhn Feyerabend Summary Feyerabend Popper non-coherent (too radical for most scientists) linear accumulation of facts (formerly predominant ) Kuhn revolutionary processes (today’s point of view) Revolutionary processes in Kuhn’s model were no new idea itself. They have been successfully used to describe art, some social sciences and politics. The new idea was to apply it to science.

22. Other questions? … “What must the world be like in order that man may know it?” (Thomas Kuhn)