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Realism vs Antirealism

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Light as transverse wave in an all-pervasive elastic medium, ether (??) 21 ... Light as quantons (??) wave-particle duality. 22 ... – PowerPoint PPT presentation

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Title: Realism vs Antirealism


1
Realism (???)vsAnti-realism (????)
2
Topics
  • The Problem of Unobservability (?????)
  • The No Miracles Argument
  • Reading Reference
  • The Observable / Unobservable Distinction
  • The Underdetermination (??????) Argument

3
The Problem of Unobservability (?????)
  • Observable ordinary objects
  • Unobservable theoretical entities (????)
  • Note theoretical ? unobservable, e.g. mass
    (??), element.

4
  • Questions
  • Do unobservable theoretical entities really exist
    and are their descriptions true?
  • Is theoretical knowledge about unobservables
    possible? (Cf. also the Problem of Induction)
  • Are unobservable theoretical constructs merely
    instruments (??) for making observable
    predictions without ontological import?
  • E.g. center of mass (??) does not refer to any
    physical objects, but a spatial point only.

5
  • Realist anti-realist interpretations of the
    kinetic theory of gases (???????)
  • It can correctly predict various observable
    behaviour of gases, e.g. Boyles Law (?????).

6
  • Realism
  • The aims of science are
  • to attain empirical adequacy
  • also to provide a true description of the
    unobservable part of reality.
  • These aims are attainable.

7
  • Antirealism
  • The aim of science is
  • to attain empirical adequacy only
  • For the unobservable part, only agnosticism
    (????) is possible.
  • Unobservable theoretical constructs should be
    taken merely as instruments for making observable
    predictions.

8
  • Copernicuss (???) theory was originally
    interpreted anti-realistically by Osiander
    (?????) who wrote the Preface for Copernicuss
    main work, On the Revolutions of the Heavenly
    Bodies (?????)
  • . . . it is the duty of an astronomer to compose
    the history of the celestial motions through
    careful and skillful observation. Then turning to
    the causes of these motions or hypotheses about
    them, he must conceive and devise, since he
    cannot in any way

9
  • attain to the true causes, such hypotheses as,
    being assumed, enable the motions to be
    calculated correctly from the principles of
    geometry, for the future as well as the past. The
    present author Copernicus has performed both
    these duties excellently. For the hypotheses need
    not be true nor even probable if they provide a
    calculus consistent with observation that alone
    is sufficient.
  • Also, some interpretations of QM.

10
The No Miracles Argument
  • The positive argument for realism is that it is
    the only philosophy that doesnt make the success
    of science a miracle Hilary Putnam (1926 - )

11
  • Main points of the argument
  • - What explains the theorys close fit with the
    observational data?
  • - Being an antirealist is akin to believing in
    miracles.
  • - So, realism is more plausible.

12
  • A historical reason for accepting the atomic
    thesis (???) in the early 20th century
  • Convergence on Avogadro's number (6.02 1023)
    under measurements in such diverse phenomena as
  • Brownian motion (????),
  • alpha decay (a??),
  • x-ray diffraction (X????),
  • electrolysis (??),
  • blackbody radiation (????), and so on.
  • What is the best explanation?

Ref. http//www.soc.iastate.edu/sapp/phil_sci_lec
ture18.html
13
  • Its an inference to the best explanation (IBE)
    (??????) / hypothetical induction (????)
  • P1 Phenomenon X Convergence on Avogadro's no.
  • P2 The atomic thesis explains X better than all
    its rivals.
  • C Hence, the atomic thesis is true.
  • (Recall the criteria of adequacy for best
    explanation.)
  • A sort of reasoning commonly used in daily life,
    e.g. the Sherlock Holmes (????) cases
  • http//etext.library.adelaide.edu.au/d/doyle/arthu
    r_conan/d75sc/chapter2.html
  • The Science of Deduction, in A Study in Scarlet.

14
  • ? - ????
  • I knew you came from Afghanistan. From long
    habit the train of thoughts ran so swiftly
    through my mind that I arrived at the conclusion
    without being conscious of intermediate steps.
    There were such steps, however. The train of
    reasoning ran, Here is a gentleman of a medical
    type, but with the air of a military man. Clearly
    an army doctor, then.

15
  • He has just come from the tropics, for his face
    is dark, and that is not the natural tint of his
    skin, for his wrists are fair. He has undergone
    hardship and sickness, as his haggard face says
    clearly. His left arm has been injured. He holds
    it in a stiff and unnatural manner. Where in the
    tropics could an English army doctor have seen
    much hardship and got his arm wounded? Clearly in
    Afghanistan. The whole train of thought did not
    occupy a second. I then remarked that you came
    from Afghanistan, and you were astonished (The
    Science of Deduction, A Study in Scarlet).

16
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17
  • An anti-realist response
  • the pessimistic meta-induction (from past
    falsity)
  • Counterexamples from the history of science
  • E.g. the phlogiston (??) theory of combustion
  • Widely accepted until the end of the 18th century

18
  • E.g. the extraordinary success of the ether (??)
    theories in the 1830s and 1840s
  • Various types of ether electrical ether, optical
    ether, caloric ether, gravitational ether,
    physiological ether, etc.
  • James Clark Maxwell (1831-1879) the ether was
    better confirmed than any other theoretical
    entity in natural philosophy.

19
  • But what do we mean by truth here?
  • Would the appealing to approximate truth rather
    than exact truth help?
  • Are empirically successful theories approximately
    true? Approaching to the ultimate truth gradually?

20
  • Difficulties from the history of optics (??)
    drastic changes of the conception of light
  • Newtons (1642-1727) theory
  • Light as beams of material corpuscles (????)
  • Fresnels (1788-1827) theory
  • Light as transverse wave in an all-pervasive
    elastic medium, ether (??)

21
  • (Modified) Maxwells (1831-1879) theory
  • Light as fluctuating electric and magnetic
    fields-in-themselves without medium
  • Quantum theory
  • Light as quantons (??) wave-particle duality

22
  • These theories were progressively empirically
    successful, but did they move closer and closer
    to the ultimate truth?
  • What is light?
  • Material particles
  • Waves in an elastic medium, ether
  • Fluctuating fields-in-themselves
  • Quantons even without clear status!
  • Next ???

23
  • Also, it seems problematic to regard, say,
    Fresnel's theory as approximately true, since
    ether a basic entity in the theory is now
    believed not to exist.
  • After all, what is approximate truth?

Would you think that this picture gives you an
approximately true depiction of the environment
if in fact there was no fog there?
24
  • Difficulties contributed by Thomas Kuhns
    (1922-1996) thesis of incommensurability (?????)
    of scientific paradigms
  • Early Kuhn Newton and Einstein were in effect
    speaking different physical languages. Comparison
    impossible.

25
  • Later Kuhn admitted the existence of common
    structure, but comparison, and hence theory
    choice, was still not fully objective.
  • So, subjective factors presumably corrupt the way
    progressing to the ultimate truth.

26
Reading Reference
  • Reading
  • French, Steven (2007). Science Key Concepts in
    Philosophy. London Continuum.
  • Chapter 7 Realism Chapter 8 Anti-realism.
  • Reference
  • http//plato.stanford.edu/entries/scientific-reali
    sm/
  • Scientific Realism
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