P160 Kuhn and his Critics

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•How are observations theory-laden?•What kind of progress can science make?•Responses to Kuhn’s account from Lakatos, Laudan, and Feyerabend.

•How are observations theory-laden?•What kind of progress can science make?•Responses to Kuhn’s account from Lakatos, Laudan, and Feyerabend.

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Relative importance of:

Relative importance of:•Unsolved puzzles?

•Solved puzzles?•Fit with data?•Puzzle-solving power?

•Unsolved puzzles?•Solved puzzles?•Fit with data?•Puzzle-solving power?

Answers depend on which paradigm you’re

in!


in!


Choose paradigm which best fits dataChoose paradigm which best fits data

Paradigm determines what the data are!

Paradigm determines what the data are!

Theory influences what

you see!

Theory influences what

you see!


Theory influences what you look forTheory influences what you look for


Don’t notice problem with card!

Don’t notice problem with card!

Don’t expect black eight of heartsDon’t expect black eight of hearts

Theory of deck: ranks: 2-10, J, Q, K, A

black suits: clubs, spadesred suits: hearts, diamonds

Theory of deck: ranks: 2-10, J, Q, K, A

black suits: clubs, spadesred suits: hearts, diamonds


Inverting gogglesexperiment:


What you’re looking at:What you’re looking at:


What you see (wearing the goggles):What you see (wearing the goggles):


But, after wearing the goggles long enough…But, after wearing the goggles long enough…


…see the world right-side up again!…see the world right-side up again!


Then, upon removing the goggles …Then, upon removing the goggles …


Things look upside down again!Things look upside down again!

WORLD + SENSE ORGANSWORLD + SENSE ORGANS

EXPERIENCEEXPERIENCE


Challenges our straightforward assumptions about observation:Challenges our straightforward assumptions about observation:

SAME EXPERIENCESAME EXPERIENCE

SAME STUFF IN WORLD + SAME SENSE ORGANSSAME STUFF IN WORLD + SAME SENSE ORGANS


Would be nice if we could be sure thatWould be nice if we could be sure that

DIFFERENT STUFF IN WORLD

DIFFERENT STUFF IN WORLD


DIFFERENT EXPERIENCE + SAME SENSE ORGANS

DIFFERENT EXPERIENCE + SAME SENSE ORGANS

Would be nice if we could be sure thatWould be nice if we could be sure that

WORLD-EXPERIENCE MATCH?WORLD-EXPERIENCE MATCH?

Different sensory input from world,SAME EXPERIENCE.

Different sensory input from world,SAME EXPERIENCE.

• Subject without goggles: tree right side up• Subject adjusted to goggles: tree right side up• Subject without goggles: tree right side up• Subject adjusted to goggles: tree right side up


Inverting goggles experiment makes us question one-to-oneInverting goggles experiment makes us question one-to-one


Same sensory input from world,DIFFERENT EXPERIENCE.

Same sensory input from world,DIFFERENT EXPERIENCE.

WORLD-EXPERIENCE MATCH?WORLD-EXPERIENCE MATCH?

• Subject without goggles: tree right side up• Subject adjusted to goggles who removes goggles: tree upside down

• Subject without goggles: tree right side up• Subject adjusted to goggles who removes goggles: tree upside down

Inverting goggles experiment makes us question one-to-oneInverting goggles experiment makes us question one-to-one


Theory influences what I experience!

Theory influences what I experience!

Theory influences how I interpret

what I experience

Theory influences how I interpret

what I experience


WORLD + SENSE ORGANS+ PARADIGM

WORLD + SENSE ORGANS+ PARADIGM

EXPERIENCEEXPERIENCE


In Normal Science:more and more solved puzzles.

In Normal Science:more and more solved puzzles.


• Truth?• Better predictions?• Better explanations?

• Truth?• Better predictions?• Better explanations?


Relative importance of:

Relative importance of:• Unsolved puzzles?

• Solved puzzles?• Fit with data?• Puzzle-solving power?

• Unsolved puzzles?• Solved puzzles?• Fit with data?• Puzzle-solving power?


in!


in!


No paradigm-free way to get an objective comparison!

No paradigm-free way to get an objective comparison!


Value:•Predictive accuracy•Consistency with other theories•Ability to unify phenomena•New ideas, discoveries

Value:•Predictive accuracy•Consistency with other theories•Ability to unify phenomena•New ideas, discoveries


Across paradigms:no guarantee of getting closer to truth!

Across paradigms:no guarantee of getting closer to truth!


Across paradigms:more puzzle-solving power?



Doesn’t fit with the rest of Kuhn’s theory!

Doesn’t fit with the rest of Kuhn’s theory!




Kuhn is right.

So much for progress.

Kuhn is right.

So much for progress.


Kuhn is wrong. How does science make progress? How to counter claim that observations are theory-laden?

Kuhn is wrong. How does science make progress? How to counter claim that observations are theory-laden?


Issue with Kuhn’s view:


Makes scientific theory change rest on “mob psychology.”

Scientific choices really come from rational competition!

Makes scientific theory change rest on “mob psychology.”

Scientific choices really come from rational competition!


Research program:Research program: Hard core

(hypotheses that aren’t changed).

Hard core (hypotheses that aren’t changed).

Protective belt(auxiliary hypotheses, may be changed).

Protective belt(auxiliary hypotheses, may be changed).


Rules for change within a research program:Rules for change within a research program:

• No changes to hard core.

• Changes to protective belt must be progressive (i.e., predict novel facts).

• No changes to hard core.

• Changes to protective belt must be progressive (i.e., predict novel facts).


Hard core (3 laws of motion, law of universal gravitation).

Hard core (3 laws of motion, law of universal gravitation).

Protective belt (how many bodies, positions, masses, etc.).

Protective belt (how many bodies, positions, masses, etc.).


Don’t change hard core.Don’t change hard core.Make progressive change to protective belt.

Make progressive change to protective belt.

Bad prediction of orbit of Uranus.Bad prediction of orbit of Uranus.

Progressive changes = predict novel facts(NOT just correcting a bad prediction)Progressive changes = predict novel facts(NOT just correcting a bad prediction)


Hard core (as is).

Hard core (as is).

Protective belt (add a planet past Uranus).

Protective belt (add a planet past Uranus).


• Now predicts orbit of Uranus accurately.

• Now predicts orbit of Uranus accurately.• Predicts novel fact: existence of Neptune (confirmed by observation with telescope).

• Predicts novel fact: existence of Neptune (confirmed by observation with telescope).

Is this a good modification of the research program?



Possible rule for choice between research programs:

Possible rule for choice between research programs:

Always prefer progressive research

programs to degenerating ones.



But, Lakatos doesn’t impose this rule!But, Lakatos doesn’t impose this rule!


• Don’t change hard core.• Don’t change hard core.• Change to protective belt: predict new planet (Vulcan).

• Change to protective belt: predict new planet (Vulcan).

Bad prediction of orbit of Mercury.Bad prediction of orbit of Mercury.


Protective belt (add a planet between Sun and Mercury).

Protective belt (add a planet between Sun and Mercury).

Hard core (as is).

Hard core (as is).


• Now predicts orbit of Mercury accurately.





• But, no novel facts (hypothesized planet Vulcan never observed).

• But, no novel facts (hypothesized planet Vulcan never observed).






Possible rule for choice betweenresearch programs:

Possible rule for choice betweenresearch programs:





OK to keep degenerating research programs around

awhile.

OK to keep degenerating research programs around

awhile.Maybe they’ll become progressive later …Maybe they’ll become progressive later …


• Rational rules for modifying a research program.

• No rational rules for choosing between research programs.

• Rational rules for modifying a research program.

• No rational rules for choosing between research programs.

So, doesn’t really make science more rational than Kuhn’s paradigm shifts!So, doesn’t really make science more rational than Kuhn’s paradigm shifts!


• Thinks Kuhn makes science look irrational.• “Research traditions”(similar to research programs).

• Thinks Kuhn makes science look irrational.• “Research traditions”(similar to research programs).

Similar to LakatosSimilar to Lakatos


Research traditions:Research

traditions:Hard core (occasionally modified)

Hard core (occasionally modified)

Protective belt (frequently modified)

Protective belt (frequently modified)


Acceptance - treat theory as true.Acceptance - treat theory as true.Pursuit - explore consequences of theory (even if it seems unlikely to be true)

Pursuit - explore consequences of theory (even if it seems unlikely to be true)Can accept one theory and pursue another!Can accept one theory and pursue another!


Accept theory with most puzzle-solving power to date.

Accept theory with most puzzle-solving power to date.Pursue theory with bestcurrent rate of puzzle-solving.

Pursue theory with bestcurrent rate of puzzle-solving.

Rule for choice between research traditions:Rule for choice between research traditions:


Makes sense of how we might accept a well-testedtheory of bridge-building …Makes sense of how we might accept a well-testedtheory of bridge-building …


… but also pursue a new, untested theory of bridge-building, to find out what we can do with it.… but also pursue a new, untested theory of bridge-building, to find out what we can do with it.


Kuhn makes all normal science depend on believing the paradigm.

Kuhn makes all normal science depend on believing the paradigm.

Scientists can research theorieswithout believing they are true!

Scientists can research theorieswithout believing they are true!


Normal science makes scientists look narrow-minded and dogmatic.

Scientific work is creative!

Normal science makes scientists look narrow-minded and dogmatic.

Scientific work is creative!




Anything goes!

Anything goes!

Science is an aspect of human creativity.

Good scientists always think outside the box.

Science is an aspect of human creativity.

Good scientists always think outside the box.


Galileo’s thought experimentGalileo’s thought experiment

What do we expect if the Earth is stationary vs. orbiting the Sun?What do we expect if the Earth is stationary vs. orbiting the Sun?


If Earth orbits Sun, expect cannonball to land far from base of tower.If Earth orbits Sun, expect cannonball to land far from base of tower.


If Earth is stationary, expect cannonball to land at base of tower.If Earth is stationary, expect cannonball to land at base of tower.

Galileo says: If Earth is orbiting the Sun,the cannonball also has a component of circularmotion sweeping it along with the Earth.

So, the cannonball would still land at the base of the tower, and the experimentcannot distinguish between a moving Earthand a stationary Earth!

So, the cannonball would still land at the base of the tower, and the experimentcannot distinguish between a moving Earthand a stationary Earth!


Rule: Theory should be responsive to observations and fit with common sense.

Rule: Theory should be responsive to observations and fit with common sense.

Anything goes!Anything goes!

Galileo’s achievement:

abandoning this rule!

Galileo’s achievement:

abandoning this rule!


Principle of tenacity:

Keep theory around so it can be fully developed.

Principle of tenacity:

Keep theory around so it can be fully developed.

Principle of proliferation:

Develop multiple theories in any given field.

Principle of proliferation:

Develop multiple theories in any given field.



• No selection mechanism or way to remove bad theories.

• Lots of labor to fully develop so many theories.

• Which theory gets used to solve practical problems? Feyerabend has no advice here!Feyerabend has no advice here!


Science may be creative, but it’s not

Art!Scientific theories

need to fit with reality!


Lakatos and Laudan:Kuhn left out the rational rules; including rational rules ensures progress.

Lakatos and Laudan:Kuhn left out the rational rules; including rational rules ensures progress.

Kuhn is right.So much for progress.



Feyerabend:Rational rules are for sissies (and so is “normal science”).

Feyerabend:Rational rules are for sissies (and so is “normal science”).




Kuhn is wrong.

How does science make progress?

Kuhn is wrong.

How does science make progress?

(What’s a better description of

science?)

(What’s a better description of

science?)


• Describe how science actually works and what it actually achieves?

• Describe what science ought to do to be objective and make progress?

• Describe how science actually works and what it actually achieves?

• Describe what science ought to do to be objective and make progress?

P160 Kuhn and his Critics

Education

Transcript of P160 Kuhn and his Critics