Do Electrons Exist? — Céline Henne: Physicist’s Views on Scientific Realism & Instrumentalism

Physics helps get stuff done. Its application has put rockets in space, semiconductors in phones, and eclipses on calendars.

For some philosophers, this is all physics offers. It is a mere instrument, albeit of great power, giving us control over tangible things. It is a set of gears and widgets (wavefunctions, strings, even electrons) to crank out predictions. In contrast to instrumentalists, scientific realists argue that the success of theories shows that they map onto the structure of the world, symbols in equations carry the imprint of real entities.

This is an old debate in the philosophy of science. While we touch on some arguments for either position, this episode focuses on the phenomenology of physics researchers. What do physicists believe?

Céline Henne is a philosopher at the University of Bologna. Alongside Hannah Tomczyk and Christopher Sperber she has fielded the most comprehensive survey of the attitudes of physicists towards the reality of the objects of their study. From looking at the answers to dozens of questions from several hundred physicists, they have distinguished several camps of belief.

It’s an elegantly designed survey, simply reading the questions forces a consideration of one’s own position.

Take the survey at scientificrealism.multiverses.xyz to see if you are an instrumentalist or a realist (or a bit of both)

As we discuss in the episode, it’s intriguing to see how ChatGPT answers the survey assuming various personas, and reflecting fairly well the positions that philosophers and physicists do take on average.

ChatGPT survey responses

These chats took place using ChatGPT 4o on May 22nd 2024

James Robinson

Imagine you are a theoretical physicist, it has been 10 years since you completed your PhD and are now a tenured professor. I will ask you thirty questions, for each one please reply with a single number from 0 to 100 representing whether you disagree entirely (0) or completely agree (100). Reply “yes” to confirm you understand.

ChatGPT

Yes.

James Robinson

Here are the questions: “Our most successful physics shows us what the world is really like.”, “Physics uncovers what the universe is made of and how it works.”, “Our most successful physics is useful in many ways, … [removed to make this doc shorter] …  best theories represents the structure of the world.”, “Having mutually conflicting theories about the same phenomena is valuable for physics.”, “Our scientific knowledge is the product of the prevailing cultural traditions and historical periods in which they were formulated”, “Scientific theories and models are idealized structures that represent the world from particular and limited points of view.”

ChatGPT

Certainly, here are the responses with the corresponding questions:

  1. “Our most successful physics shows us what the world is really like.” – 75
  2. “Physics uncovers what the universe is made of and how it works.” – 90
  3. “Our most successful physics is useful in many ways, but physics does not reveal the true nature of the world.” – 30
  4. “The imperceptible objects that are part of our most successful physics probably exist. (with ‘imperceptible’ we mean objects that cannot be perceived with our unaided senses, e.g. electrons, black holes, …)” – 85
  5. “The imperceptible objects postulated by physics are only useful fictions.” – 20
  6. “Physicists discover imperceptible objects.” – 80
  7. “Communities of physicists construct imperceptible objects.” – 60
  8. “Our best physical theories are true or approximately true.” – 70
  9. “Physical theories do not reveal hidden aspects of nature. Instead, they are instruments for the classification, manipulation and prediction of phenomena.” – 40
  10. “The most important goal of physics is giving us true theories.” – 80
  11. “If there was a highly advanced civilization in another galaxy, their scientists would discover the existence and properties of many of the imperceptible objects of our current physics.” – 90
  12. “I expect the best current theories in physics to be largely refuted in the next centuries – in the same way that successful theories were largely refuted in the past.” – 50
  13. “Electrons exist.” – 95
  14. “Electrons, with all their properties, exist ‘out there,’ independently from our theories.” – 85
  15. “Our theories are getting closer to the real nature of the electron.” – 75
  16. “Electrons are postulated as real within our models; it does not make sense to ask whether they exist ‘outside’ or independently of the theory/model.” – 55
  17. “There is something in the world that behaves like (what we would define as) an electron.” – 70
  18. “Electrons are (at least) as real as toe-nails and volcanoes.” – 90
  19. “Phonons exist.” – 70
  20. “There really was a Big Bang.” – 80
  21. “General relativity is a true theory.” – 85
  22. “General relativity teaches us about the nature of spacetime.” – 80
  23. “General relativity is not the revelation of an underlying order of nature. It is a tool that helps us make predictions and construct GPS, for example.” – 40
  24. “Newtonian mechanics is a true theory.” – 60
  25. “If a phenomenon can be explained both by a classical model and by a quantum model, neither of the models is closer to the truth than the other.” – 50
  26. “We should build a particle collider that is bigger than the LHC.” – 70
  27. “A physical theory cannot tell us what the universe is really made of, but the mathematical structure of our best theories represents the structure of the world.” – 80
  28. “Having mutually conflicting theories about the same phenomena is valuable for physics.” – 65
  29. “Our scientific knowledge is the product of the prevailing cultural traditions and historical periods in which they were formulated.” – 60
  30. “Scientific theories and models are idealized structures that represent the world from particular and limited points of view.” – 75

Second chat (separate)

Imagine you are a philosopher of science, it has been 10 years since you completed your PhD and are now a tenured professor. I will ask you thirty questions, for each one please reply with a single number from 0 to 100 representing whether you disagree entirely (0) or completely agree (100). Reply “yes” to confirm you understand.

ChatGPT

Yes.

James Robinson

Here are the questions: “Our most …  of the prevailing cultural traditions and historical periods in which they were formulated”, “Scientific theories and models are idealized structures that represent the world from particular and limited points of view.”

ChatGPT

Here are my responses:

  1. “Our most successful physics shows us what the world is really like.” – 60
  2. “Physics uncovers what the universe is made of and how it works.” – 70
  3. “Our most successful physics is useful in many ways, but physics does not reveal the true nature of the world.” – 50
  4. “The imperceptible objects that are part of our most successful physics probably exist. (with ‘imperceptible’ we mean objects that cannot be perceived with our unaided senses, e.g. electrons, black holes, …)” – 80
  5. “The imperceptible objects postulated by physics are only useful fictions.” – 40
  6. “Physicists discover imperceptible objects.” – 65
  7. “Communities of physicists construct imperceptible objects.” – 55
  8. “Our best physical theories are true or approximately true.” – 70
  9. “Physical theories do not reveal hidden aspects of nature. Instead, they are instruments for the classification, manipulation and prediction of phenomena.” – 45
  10. “The most important goal of physics is giving us true theories.” – 75
  11. “If there was a highly advanced civilization in another galaxy, their scientists would discover the existence and properties of many of the imperceptible objects of our current physics.” – 60
  12. “I expect the best current theories in physics to be largely refuted in the next centuries – in the same way that successful theories were largely refuted in the past.” – 70
  13. “Electrons exist.” – 85
  14. “Electrons, with all their properties, exist ‘out there,’ independently from our theories.” – 75
  15. “Our theories are getting closer to the real nature of the electron.” – 65
  16. “Electrons are postulated as real within our models; it does not make sense to ask whether they exist ‘outside’ or independently of the theory/model.” – 50
  17. “There is something in the world that behaves like (what we would define as) an electron.” – 80
  18. “Electrons are (at least) as real as toe-nails and volcanoes.” – 70
  19. “Phonons exist.” – 60
  20. “There really was a Big Bang.” – 85
  21. “General relativity is a true theory” – 70
  22. “General relativity teaches us about the nature of spacetime” – 75
  23. “General relativity is not the revelation of an underlying order of nature. It is a tool that helps us make predictions and construct GPS, for example.” – 55
  24. “Newtonian mechanics is a true theory” – 40
  25. “If a phenomenon can be explained both by a classical model and by a quantum model, neither of the models is closer to the truth than the other.” – 50
  26. “We should build a particle collider that is bigger than the LHC.” – 70
  27. “A physical theory cannot tell us what the universe is really made of, but the mathematical structure of our best theories represents the structure of the world.” – 60
  28. “Having mutually conflicting theories about the same phenomena is valuable for physics.” – 65
  29. “Our scientific knowledge is the product of the prevailing cultural traditions and historical periods in which they were formulated” – 50
  30. “Scientific theories and models are idealized structures that represent the world from particular and limited points of view.” – 65

In a third chat:

James Robinson

Imagine you are an Instagram influencer and performance poet. I will ask you thirty questions, for each one please reply with a single number from 0 to 100 representing whether you disagree entirely (0) or completely agree (100). Reply “yes” to confirm you understand.

ChatGPT

  “Our most successful physics shows us what the world is really like.”: 75,

    “Physics uncovers what the universe is made of and how it works.”: 80,

    “Our most successful physics is useful in many ways, but physics does not reveal the true nature of the world.”: 50,

    “The imperceptible objects that are part of our most successful physics probably exist.”: 85,

    “The imperceptible objects postulated by physics are only useful fictions.”: 40,

    “Physicists discover imperceptible objects.”: 70,

    “Communities of physicists construct imperceptible objects.”: 60,

    “Our best physical theories are true or approximately true.”: 65,

    “Physical theories do not reveal hidden aspects of nature. Instead, they are instruments for the classification, manipulation and prediction of phenomena.”: 55,

    “The most important goal of physics is giving us true theories.”: 90,

    “If there was a highly advanced civilization in another galaxy, their scientists would discover the existence and properties of many of the imperceptible objects of our current physics.”: 75,

    “I expect the best current theories in physics to be largely refuted in the next centuries – in the same way that successful theories were largely refuted in the past.”: 60,

    “Electrons exist.”: 95,

    “Electrons, with all their properties, exist ‘out there,’ independently from our theories.”: 85,

    “Our theories are getting closer to the real nature of the electron.”: 70,

    “Electrons are postulated as real within our models; it does not make sense to ask whether they exist ‘outside’ or independently of the theory/model.”: 50,

    “There is something in the world that behaves like (what we would define as) an electron.”: 90,

    “Electrons are (at least) as real as toe-nails and volcanoes.”: 80,

    “Phonons exist.”: 70,

    “There really was a Big Bang.”: 85,

    “General relativity is a true theory”: 75,

    “General relativity teaches us about the nature of spacetime”: 80,

    “General relativity is not the revelation of an underlying order of nature. It is a tool that helps us make predictions and construct GPS, for example.”: 65,

    “Newtonian mechanics is a true theory”: 60,

    “If a phenomenon can be explained both by a classical model and by a quantum model, neither of the models is closer to the truth than the other.”: 50,

    “We should build a particle collider that is bigger than the LHC.”: 70,

    “A physical theory cannot tell us what the universe is really made of, but the mathematical structure of our best theories represents the structure of the world.”: 65,

    “Having mutually conflicting theories about the same phenomena is valuable for physics.”: 55,

    “Our scientific knowledge is the product of the prevailing cultural traditions and historical periods in which they were formulated”: 75,

    “Scientific theories and models are idealized structures that represent the world from particular and limited points of view.”: 70

David Papineau: How Philosophy Serves Science

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