Model-dependent realism

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In philosophy, model-dependent realism asserts that there is no "objective" or "unique" external reality, but reality consists at least in part of networks of models, or pictures that connect observations and their explanations.

A model or picture consists of the combination of a set of observations accompanied by theoretical concepts that explain and connect those observations. There is no requirement that a model be unique, or even that the data include all available observations. Data described equally well by different models all have equal claim to be valid. The universe of all observations possibly may be covered by a network of overlapping models and, where overlap occurs; multiple, equally valid, models exist.

Outline

Recently the connection between theory and observations has been explored by physicists Stephen W. Hawking and Leonard Mlodinow in their book: The Grand Design, where they propose the notion of a model-dependent reality.[1] They point out:

  • that either an earth-centered (Ptolemaic) or a sun-centered (Copernican) picture of reality can be made consistent with the motion of celestial bodies;
  • that goldfish physicists living in a curved bowl, though observing curved paths of motion of bodies that we observe as linear, could still formulate predictive laws governing motion as they see it;
  • that we cannot know whether we live in a simulated world, a virtual reality, one that the simulators rendered self-consistent.

Each of those models is not only data-dependent, but is theory-dependent.

Hawking/Mlodinow introduce a model as follows:

... a physical theory or world picture is a model (generally of a mathematical nature) and a set of rules that connect the elements of the model to observations. This provides a framework with which to interpret modern science.[2]

This quotation defines a "model". This concept of "model" is extended to a wider class of mental constructs in the metaphysical position of model-dependent realism as proposed below:

According to the idea of model-dependent realism...our brains interpret the input from our sensory organs by making a model of the outside world. We form mental concepts of our home, trees, other people, the electricity that flows from wall sockets, atoms, molecules, and other universes. These mental concepts are the only reality we can know. There is no model-independent test of reality. It follows that a well-constructed model creates a reality of its own.[2]

In comparing different models,

Model-dependent realism short circuits all this argument and discussion between the realist and anti-realist schools of thought. According to model-dependent realism, it is pointless to ask whether a model is real, only whether it agrees with observation. If there are two models that both agree with observation,...then one cannot say that one is more real than another. (pp. 45-46)

If two different models agree with the observations, to consider one more true than the other, to say that one gives a truer picture of reality than the other, involves considerations outside the concept of model-independent reality, to consider possibly subjective matters such as which may be more convenient to employ in a given situation, more elegant, more intriguing, or otherwise more appealing.

Some find the ambiguity introduced by alternative equivalent model-dependent realities to be a defect of the concept of model-dependent realities.[3] That position, however, is based upon outside criteria, and an example of such criteria is provided shortly.

It should be emphasized that there is no restriction that a model use only observable or measurable constructs. The alternatives:

Do unobservable theoretical entities such as quarks and gluons really exist in the physical world, as objective entities independent of human will, or exist merely as human constructions for their utility in organizing our experience and predicting future events?[4]

are addressed by Hawking/Mlodinow in their definition of a model as follows:

QCD [Quantum chromodynamics] also has a property called asymptotic freedom, which we referred to, without naming it, in Chapter 3. Asymptotic freedom means that the strong forces between quarks are small when the quarks are close together but increase if they are farther apart, rather as though they were joined by rubber bands. Asymptotic freedom explains why we don’t see isolated quarks in nature and have been unable to produce them in the laboratory. Still, even though we cannot observe individual quarks, we accept the model because it works so well at explaining the behavior of protons, neutrons, and other particles of matter [Emphasis added]. [5]

Therefore, the definition of a model adopts any unobservable constructs as aspects of the model.[Note 1] With this interpretation of a model, the alternatives posed by Cao above[4] are confronted by the metaphysical position of model-dependent realism first by rejection of any posit of "objective" reality and restriction of reality to networks of constituent models, and second, like the models themselves, model-dependent realism accepts any unobservable entities used to connect selected observations.

Background

The "reality" of science, even when restricted to the interpretation of observations and measurements, has been much discussed. Pierre Duhem (1861-1916) held that while physical theory was no more than an aid to memory, summarizing and classifying facts by providing a symbolic representation of them, the facts of physical theory are to be distinguished from common sense and metaphysics. His views were further developed by W. V. O. Quine (1908-2000), who suggested "“our statements about the external world face the tribunal of sense experience not individually, but only as a corporate body”. It is impossible to test a scientific hypothesis in isolation, but only as part of a system. These two authors were much concerned with how a theory was coupled to concrete observation and measurement, and how it morphed with admission of new data.[6][7]

The evolution of science forms part of this discussion. For example, Thomas Kuhn connected changes in scientists' views of reality to "revolutions" in science and changes in "paradigms".[8] As an example, Kuhn suggested that the "Copernican revolution" replaced the views of Ptolemy not because of empirical failures, but because of a new "paradigm" that exerted control over what scientists felt to be the more fruitful way to pursue their goals. Such historical analysis goes beyond the concept of a model-dependent reality itself to involve comparisons, a critique of overlapping model-dependent realities, and an assessment of their roles.

The matter is made more complicated by attempts to extend observations of scientific practice to wider realms, including religious systems, in an attempt to compare them. A key author in this arena was Barbour who proposed an approach called critical realism.[9] The word "critical" refers to reflection and analysis. This broad extension lies outside the realm of model-dependent realism itself, and falls into a much vaguer and more tendentious arena.

Model assessment

Many models may be proposed, and the issue of comparing, ranking, and generally critiquing them arises.

For example, quantum mechanics, which is a model describing (among other matters) atomic interactions, despite its experimental success, is commonly called incomplete as it is "not accompanied by an interpretation that is widely convincing."[10] Steven Pinker discusses this question using several quotations, including one from Murray Gell-Mann that describes quantum theory as: "that mysterious, confusing discipline which none of us really understands but which we know how to use."[11] These reservations about quantum mechanics appear to seek something more than a model, what might be called physical intuition, or visualization.[Note 2]

Hawking/Mlodinov do not address the intuitive qualities of a model, or scientists' personal opinions of them, but they do raise the question of what constitutes a good model. They suggest a "good model" has these characteristics:(p. 51[1])

  1. It is elegant
  2. Contains few arbitrary or adjustable elements
  3. Agrees with and explains all existing observations
  4. Makes detailed predictions about future observations that can disprove or falsify the model if they are not borne out.

The features of a "good" theory have been debated for centuries.[Note 3] The last criterion on this list is related to the criterion proposed by Popper:[12]

It must be possible for an empirical scientific system to be refuted by experience.

Five somewhat similar criteria were proposed by Kuhn as what he called "the shared basis for theory choice", a list selected "not because they are exhaustive, but because they are individually important and collectively sufficiently varied to indicate what is at stake."[13]

These desiderata of a "good model" allow a critique of different models. These "principles of comparison" may have a justification beyond mere general acceptance.[Note 4]

Unfortunately, even the most successful model of modern science, the Standard Model of particle physics, satisfies only the last criterion. As said by Hawking/Mlodinov (p. 52[1]):

..many people view the "standard model" ...as inelegant. ...it contains dozens of adjustable parameters whose values must be fixed to match observations, rather than being determined by the theory itself.

The Standard Model fails the third criterion in not encompassing gravitation. Hawking/Mlodinov (p. 58[1]) deal with the failure of a theory to encompass all observations using the notion of a network of overlapping theories, each describing some observations and agreeing with one another where the theories overlap. To quote:(p. 58[1]):

No single theory within the network can describe every aspect of the universe... Though this situation does not fulfill the traditional physicists' dream of a single unified theory, it is acceptable within the framework of model-dependent realism.

Presumably, each theory included in a network provides concepts for a "model-dependent reality", though that reality is restricted to the domain of data to which it applies. Where these model-dependent realities overlap, multiple interpretations of reality are available of equal value.

Data collection

...the measuring device has been constructed by the observer, and we have to remember that what we observe is not nature in itself but nature exposed to our method of questioning.
—Werner Heisenberg, Physics and Philosophy[14]

The definition of a model given by Hawking/Mlodinow is pretty straightforward if one has in mind a particular set of data to explain. Either the model explains the data or it doesn't, and if two models explain the data differently, any claim for the concepts employed by either as more true of "reality" must be based upon criteria lying outside the reach of model-dependent reality, such as the desiderata for a "good model" listed earlier.

The matter is less clear when one considers the selection of just what "data" must be explained. Our senses are limited, and we accept that we cannot see and hear everything that comprises reality. So we supplement the senses, for example, by using a telescope or a microscope. Historically the issue arose as to whether such instruments deceived us, and gradually they have been accepted as extensions of our natural capacities.[15][16]

The gathering of "data" supplementing our senses has gone far beyond the primitive telescope to its modern version (for example, the Hubble telescope) and the microscope to its modern version (for example, the scanning tunneling microscope).[17][18] Today experiments may require expensive apparatus not available to all, involving observations not even interpretable by many. Examples are the colliders of high-energy physics,[19] and the sophisticated electronic image acquisition of modern astronomy, guided by elaborate computer processing and filtering.[20] One might reasonably ask how well the acquisition of "data" is separated from the "theory" that explains how the acquisition process works, and that often suggests where to look for new "data". The process by which data is allowed into the theory influences what is incorporated into "reality".

The gathering of data is complicated by the limited access to these data-acquisition instruments, both in a required training that could be seen as indoctrination (not necessarily deliberate, but de facto), and in limitations upon who, and what investigations, are worthy to use the instruments, as determined by various funding agencies and corporate laboratories. Although censorship is not the motivation directing government and corporate support, a preoccupation with popular and/or commercially attractive projects draws resources and talent away from less conspicuous goals potentially of more significance to a comprehensive "reality".[21][22][23] In effect, the expense and expertise of modern research result in blinkers.[24][25][26]

The analysis as well as the gathering of data is becoming more complicated as our very notion of thinking, even of mathematical proof, is modified by technology, for example, by computers. Theoretical predictions are made by computer simulations that perform calculations beyond human capacity. The concepts entering a model-based reality may be only implicit in a computer programmable code, in open-ended algorithms, and may not be concepts the human mind is aware of directly.[27]

To a limited degree, the shaping of "reality" based upon modeling of selected data is a public enterprise, with all the foibles that implies. The public does not engage reality at a specialized deeply technical level, but at a metaphoric level:

All theories have metaphorical dimensions...that give depth and meaning to scientific ideas, that add to their persuasiveness and color the way we see reality."[28]

An explicitly metaphoric public participation is "eco-consciousness".[29] Metaphorical involvement also is evident in arenas such as gene research and genetically altered organisms, and investigations of stem cells, where the public is actively engaged.[30] Another example is archaeology and the limitations exerted upon examination of burial sites.[31][32] In some cases public participation leads to simple clamor, as in the case of global warming.[33][34] This broad public engagement, frequently informed by vested interests and oversimplifications, facilitates manipulation by groups with their own objectives, similar to the censorship found in the times of Vesalius and Galileo although lacking some of that institutional authority.[35]

Although the above examples suggest an indictment of metaphor as a foible of public participation in shaping reality, public engagement in some form is necessary and desirable, and ultimately a goal of the entire enterprise.

Notes

  1. ↑ One might ask how arbitrary concepts enter this view of reality. For example, in electromagnetic theory one can introduce a vector and a scalar potential, neither of which is unique, and is free to choose an admixture of the two called a "gauge". Apparently then, one could view each different gauge as a feature of reality in one of a family of overlapping realities, all of which describe the same observations. A contrasting view is found in: Gorden N Fleming (2004). Martin Carrier, Gerald J. Massey, Laura Ruetsche, eds: Science at century's end: philosophical questions on the progress and limits. Pittsburgh University Press, p. 244. ISBN 0822958201. “But the gauge-independent formalism would delineate the aspects of the the theory one could safely take seriously, the aspects one could tentatively invest with ontological content.” 
  2. ↑ Quoting Feynman about his creative process: "It is impossible to differentiate the symbols from the thing; but it is very visual. It is hard to believe it, but I see these things not as mathematical expressions but a mixture of a mathematical expression wrapped into and around, in a vague way, around the object. So I see all the time visual things associated with what I am trying to do." Silvan S. Schweber (1994). QED and the men who made it: Dyson, Feynman, Schwinger, and Tomonaga. Princeton University Press, p. 465. ISBN 0691033277.  A more technical description is provided by Adrian Wüthrich (2010). The Genesis of Feynman Diagrams. Springer, p.9. ISBN 9048192277. 
  3. ↑ For example, Einstein and Heisenberg had an extensive exchange over whether a good theory could contain unobservable quantities. Einstein said it was unavoidable, while Heisenberg's aesthetic was to have every item in the theory directly observable. See: Manjit Kumar (2011). Quantum: Einstein, Bohr, and the Great Debate about the Nature of Reality. W W Norton & Company, pp. 226 ff. ISBN 0393339882.  John Slater took the view that theory was experiment's handmaid: "Questions about a theory which do not affect its ability to predict experimental results correctly seem to me quibbles about words, ..." See James Gleick (1993). Genius: The Life and Science of Richard Feynman. Vintage. ISBN 0679747044. . Einstein felt that "elegance" was related to parsimony: the fewer the postulates the better. Lorentz thought it was related to adaptability to new observations. Feynman and Dyson had contrasting views as well: Feynman wanted a picture the mind could grasp expressing the unity of nature, while Dyson wanted only a theory that would work within set limits. A description of the encounter between Feynman and Dyson during a four-day drive to Albuquerque is found in: Walter Gratzer (2004). Eurekas and euphorias: the Oxford book of scientific anecdotes. Oxford University Press, p. 104. ISBN 019860940X. “Feynman distrusted Dyson's mathematics, and Dyson suspected Feynman's intuition.” 
  4. ↑ For further discussion of the appraisal of theories see, for example, W. Newton-Smith (1981). “Chapter V: TS Kuhn: from revolutionary to social democrat; §3: The five ways”, The Rationality of Science. Psychology Press, pp. 112 ff. ISBN 0415058775. “The fact that science is progressing in the sense of generating theories of greater verisimilitude provides reason for thinking that the methods employed (the principles of comparison) are in fact legitimate evidential principles.”  The four desiderata of a good model by Hawking/Mlodinov are expressed differently as "the five ways", a partial list of principles of comparison attributed to Kuhn, author of a well known book (called one of the most influential books since WW II by The Times Literary Supplement) Thomas S Kuhn (1966). The structure of scientific revolutions, 3rd ed. University of Chicago Press. ISBN 0226458083. .

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 Hawking SW, Mlodinow L. (2010). The Grand Design, Kindle edition. New York: Bantam Books. ISBN 978-0-553-90707-0. 
  2. ↑ 2.0 2.1 Hawking SW, Mlodinow L.. “Chapter 3: What is reality?”, cited work, pp. 42-43. ISBN 0553805371. 
  3. ↑ This argument is attributed to Thomas Kuhn in Tian Yu Cao (2010). From Current Algebra to Quantum Chromodynamics: A Case for Structural Realism. Cambridge University Press, p. 4. ISBN 0521889332. 
  4. ↑ 4.0 4.1 This question is a close paraphrase of a statement in Tian Yu Cao (2010). From Current Algebra to Quantum Chromodynamics: A Case for Structural Realism. Cambridge University Press, pp. 2-3. ISBN 0521889332. 
  5. ↑ See above reference: Hawking SW, Mlodinow L. (2010). “Chapter 5: The theory of everything”, The Grand Design, p. 110. ISBN 978-0-553-90707-0. 
  6. ↑ Roger Ariew (2011). Edward N. Zalta ed.:Pierre Duhem. The Standard Encyclopedia of Philosophy (Spring 2011 edition). Retrieved on 2011-08-26.
  7. ↑ Peter Hylton (2010). Edward N. Zalta ed.:Willard van Orman Quine. The Stanford Encyclopedia of Philosophy (Fall 2010 Edition). Retrieved on 2011-08-26.
  8. ↑ Thomas S Kuhn (1966). The structure of scientific revolutions, 3rd ed. University of Chicago Press. ISBN 0226458083. 
  9. ↑ Niels Henrik Gregersen (2004). “Chapter 4: Critical realism and other realisms”, Robert J. Russell, ed: Fifty years in science and religion: Ian G. Barbour and his legacy. Ashgate Publishing, Ltd, pp. 78 ff. ISBN 075464118X. 
  10. ↑ Gordon N Fleming (2004). “Limits and the future of quantum theory”, Martin Carrier, Gerald J. Massey, Laura Ruetsche, eds: Science at century's end: philosophical questions on the progress and limits of science. University of Pittsburgh Press, pp. 237 ff. ISBN 0822958201. 
  11. ↑ Steven Pinker (2003). The blank slate: the modern denial of human nature. Penguin, p. 347. ISBN 0142003344. 
  12. ↑ Karl Raimund Popper (2002). The logic of scientific discovery, Reprint of translation of 1935 Logik der Forchung. Routledge/Taylor & Francis Group, p. 18. ISBN 0415278430. 
  13. ↑ Thomas S Kuhn (2007). “Chapter 10: Objectivity, Value Judgement and Theory Choice”, Marc Lange (ed.): Philosophy of science: an anthology, Reprint of 1977 paper in The Essential Tension. Wiley-Blackwell. ISBN 1405130342. 
  14. ↑ Werner Heisenberg (2007). “Chapter III: The Copenhagen interpretation of quantum theory”, Physics and Philosophy: The Revolution in Modern Science, Reprint of Harper & Row 1962 ed. New York: Harper Perennial Modern Classics, p. 58. ISBN 0061209198. 
  15. ↑ Initially, many refused to believe the results of the telescope. Kepler wrote to Galileo that such persons were "stuck in a world of paper" , blind not by force of circumstance but of their own foolish will. Dan Hofstadter (2009). “Chapter 2: The telescope; or seeing”, The Earth Moves: Galileo and the Roman Inquisition. W W Norton & Co, pp. 53 ff. ISBN 978-0-393-06650-0. 
  16. ↑ Cautions abound concerning the deceptive nature of the microscope. For example, see Hermann Schacht (1855). The microscope: and its application to vegetable anatomy and physiology, 2nd ed. S. Highley, p. 57. “Seeing, as Schleiden justly observes, is a difficult art, and seeing with the microscope is yet more difficult...” 
  17. ↑ Hubble space telescope. NASA. Retrieved on 2011-07-30.
  18. ↑ The scanning tunneling microscope. Nobelprize.org. Retrieved on 2011-07-30.
  19. ↑ The large hadron collider. CERN. Retrieved on 2011-07-26.
  20. ↑ Most telescopic images are collected today using the charge-coupled device or CCD, and computer processed. See, for example, Steve B. Howell (2006). Handbook of CCD astronomy, Volume 5 of Cambridge observing handbooks for research astronomers; 2nd ed. Cambridge University Press. ISBN 0521617626.  In addition, the telescope itself is aimed and adjusted using computer programs.
  21. ↑ For example, even in the very liberal environment of Bell Laboratories engaged in "fundamental research", experiments following discovery of the cosmic background radiation by Arno Penzias and Robert Woodrow Wilson were frowned upon. So was much of the research underlying the modern integrated circuit, research that had to be conducted in the wee hours of the morning, so as not to interfere with "important" corporate research.
  22. ↑ As Wilson gently recalled matters: "local management here decided that we had had our fun doing astronomy and that now we really ought to contribute something to the telephone company too". Quoted in Jeremy Bernstein (1987). “Chapter 14: Robert Wilson”, Three degrees above zero: Bell Laboratories in the information age. Cambridge University Press, p. 208. ISBN 0521329833. 
  23. ↑ Concerning the environment at Bell, see for example, Michael Riordan, Lillian Hoddeson (1997). Crystal fire: the birth of the information age. W. W. Norton & Company, p. 179. ISBN 0393041247. “But because they could not get even a small laboratory dedicated to them, they put it [their crystal-pulling apparatus] on a set of wheels so that it could be rolled into and out of a storage closet in the metallurgical lab. Working on their own time,..., they managed to "bootleg" their crystal growing program into existence.”  Corporate official "history" has glossed over these problems to present a view of great wisdom and encouragement.
  24. ↑ Derek J.De Solla Price (1986). Little Science, Big Science and beyond. Columbia University Press. ISBN 0231049560. 
  25. ↑ Lee Smolin (2007). “Chapter 16: How do you fight sociology”, The trouble with physics: the rise of string theory, the fall of a science, and what comes next. Houghton Mifflin Harcourt, pp. 261 ff. ISBN 061891868X. 
  26. ↑ Peter Woit (2006). “Chapter 16: The only game in town: the power and the glory of string theory”, Not even wrong: the failure of string theory and the search for unity in physical law. Basic Books, pp. 221 ff. ISBN 0465092756. 
  27. ↑ Timothy R. Colburn (2000). “Chapter 6: Models of the mind”, Philosophy and computer science. ME Sharpe, Inc., pp. 68 ff. ISBN 156324991X. 
  28. ↑ Brian Goodwin (2001). “The myth behind the metaphors”, How the Leopard Changed Its Spots: The Evolution of Complexity, Reprint with a new preface of 1994 ed. Princeton University Press, p. 33. ISBN 0691088098.  Title links to Google Books preview.
  29. ↑ Larson B (2011). Metaphors for Environmental Sustainability: Redefining Our Relationship with Nature. Yale University Press. ISBN 9780300151534..  Science magazine book review.
  30. ↑ Gregory Pence (2007). “Chapter 7: Recreating nature: Patenting human genes?”, Re-Creating Medicine: Ethical Issues at the Frontiers of Medicine. Rowman & Littlefield, pp. 137 ff. ISBN 084769691X. 
  31. ↑ David Hurst Thomas (2001). Skull Wars: Kennewick Man, Archaeology, and the Battle for Native American Identity. Basic Books. ISBN 046509225X. 
  32. ↑ Robert L. Kelly, David Hurst Thomas (2009). Archaeology, 5th ed. Cengage Learning, p. xxxiii. ISBN 0495602914. “How can we pursue this laudable goal if the very act of conducting research offends the living descendents of the ancient people being studied?” 
  33. ↑ For a discussion by a proponent of intelligent design, see for example Roy W. Spencer (2010). Climate Confusion: How global warming hysteria leads to bad science, pandering politicians and misguided policies that hurt the poor, Paperback version of 2008 ed. Encounter Books. ISBN 1594033455. 
  34. ↑ James Hoggan, Richard D. Littlemore (2009). Climate cover-up: the crusade to deny global warming. Greystone Books. ISBN 1553654854. 
  35. ↑ Andrew Dickson White (1896). A history of the warfare of science with theology in Christendom, Volume 2. D. Appleton & Co.. 
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