The role of Experiment in scientific research Mikkel Willum Johansen [email protected].

The role of Experiment in scientific research

Mikkel Willum [email protected]

Two different roles1) Creation of phenomena (Ian Hacking)2) Testing of theory

The role of the experiment

The hypothetico-deductive method1) State a theory (a bold hypothesis)2) Deduce empirically testable consequences3) Conduct the test(s)4) Adjust, if your hypothesis is falsified

Scientific theories

Absolute truth

Time

Karl Popper’s picture of scientific development

Brahes and the parallax

Parallax

Brahes and the parallax

Brahes argument1. If the Earth revolves around the Sun, it

must be possible to observe a parallax with my instruments

2. It isn’t possible to observe a parallax∴ The Earth doesn’t revolve around the

Sun

Brahes and the parallax

Brahes argument1. If …

… the Earth revolves around the Sun… the Stars stand still… light travels in straight lines… the Universe is not ridiculously big……… then it must be possible to observe a parallax with my instruments

2. It isn’t possible to observe a parallax

∴ At least one of the hypothesis above must be false

The web of beliefs

“The totality of our so-called knowledge … is a man-made fabric which impinges on experience only along the edges ... A conflict with experience at the periphery occasions readjustments in the interior of the field. Truth values have to be redistributed over some of our statements. Reëvaluation of some statements entails reëvaluation of others, because of their logical interconnections … But the total field is so underdetermined by its boundary conditions, experience, that there is much latitude of choice as to what statements to reëvaluate in the light of any single contrary experience.”

(Willard V. O. Quine: ”Two Dogmas of Empiricism”, 1951)

Quine (1908-2000)

Experimenters regress

Experiments only tell us something, if they are donecompetently, but when is that?

In training: When we get the right result

In real time science: ?

To know the right answer, we must make successful experiments, but to know whether an experiments is successful or not, we most know the right answer

Edible knowledge

Planarian

Period: Late 1950s to mid-1970sMain figures: James McConnell and George UngarMcConnell’s experiment:

Edible knowledge

Period: Late 1950s to mid-1970sMain figures: James McConnell and George UngarMcConnell’s experiment:

Edible knowledge

+-

Period: Late 1950s to mid-1970sMain figures: James McConnell and George UngarMcConnell’s experiment:

Edible knowledge

Period: Late 1950s to mid-1970sMain figures: James McConnell and George UngarMcConnell’s experiment:

Edible knowledge

Trained worm

Period: Late 1950s to mid-1970sMain figures: James McConnell and George UngarMcConnell’s experiment:

The 1962 resultWhen trained worms are fed to untrained, the untrained worms become 1.5 times more likely to respond to light

Edible knowledge – the controversy

Which variables are important for the experiment?• Slime• Treatment of the worms• Species and size of the worms• Housing (dark or light?)• Nature of the electric shock• Barometric pressure • Skilled practice (golden hands)

Experimenter’s regress• It is unknown which factors might influence the experiment =>• It is unknown what constitutes a succesfull experiment

Edible knowledge – the controversy

(Collins & Pinch p. 16)

Scientific controversy

Scientists reasons for believing or disbelieving acontroversial experiment (based on interviews)1. Faith in a scientist’s experimental capabilities and honesty,

based on previous working partnership2. The personality and intelligence of experimenters3. A scientist’s reputation gained in running a huge lab4. Whether or not the scientist is worked in industry or academia5. A scientist’s previous history of failures6. Inside information7. Scientists’ style and presentation of results8. Scientists’ psychological approach to experiment9. The size and prestige of the scientist’s university of origin10. The scientist’s integration into various scientific networks11. The scientists nationality

(Collins and Pinch, p. 101)

James McConnell’s The Worm Re-Turns: The Best of from the Worm Runner’s Digest p.11

(Collins & Pinch p. 17)

The Hypothetico-deductive method1) State a theory (a bold hypothesis)2) Deduce empirically testable consequences3) Conduct the test(s)4) Adjust, if your hypothesis is falsified

Scientific theories

Absolute truth

Time

Karl Popper’s picture of scientific development

Perspectives and conclusion

Perspectives and conclusion

Experimenters regressTo know the right answer, we must make successful experiments, but to know whether an experiments is successful or not, we most know the right answer

Perspectives1) What happens when commercial interests enters

the debate?2) When are scientists dishonest?3) Uncertainty

Perspectives and conclusion

”The aim of this book is to explain the golem that is science. We aim to show that it is not an evil creature but it is a little daft. Goem Sceince is not to be blamed for its mistakes; they are our mistakes. A gollem cannot blamed if it is doing its best. But we must not expect too much. A golem, powerful though it is, is the creature of our art and our craft.”

(Collins & Pinch, p. 2)