Physics and the 'Real Patterns' theory of ontology' _'Emergence in

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					Physics and the ‗Real Patterns‘
      theory of ontology‘

            James Ladyman
  Thanks to Joss and Richard
    and the Lorentz Centre
• The document that describes the topic of the
  conference does a great job of identifying a
  lot of important and fascinating issues.
• Thanks to the physicists for informing us
  about the relevant phenomena.
• My ideas owe a lot to my co-authors Steven
  French and Don Ross.
• The material on phlogiston is forthcoming in a
  paper in Synthese
               Three Ideas
1. Structure is retained on theory change even
   when ontology is not.
2. Structuralism about a domain involves the
   idea that the entities in the domain are
   mutually dependent on each other for their
   existence/individuation.
3. Real Patterns

  – In the case of physical structures I contend that
    these three ideas all centrally involve modality.
 Of what is everything made?
• Western philosophy allegedly started when
  the pre-Socratics asked this question.
• This is a metaphysical question physics is
  supposed to answer.
• It presupposes that the world comes in a
  hierarchy of levels and that there is a
  fundamental level with a few basic kinds of
  entities.
• The most naïve picture is one of physical
  objects ordered by (spatial) size and
  ultimately composed of elementary particles.
                   Levels
• There is not necessarily a single hierarchy

• Ordering by spatiotemporal scale
• Ordering by energy
• Ordering by composition

• Anomalous sciences: evolution, game theory,
  economics, thermodynamics,
        Scepticism about Levels
• Spatiotemporal scale may not be a fundamental feature of
  reality. It is an open question whether quantum gravity will take
  the spatiotemporal manifold as primitive rather than emergence.
• The same may be true of the energy scale.
• The levels structure based on the composition relation is
  undermined by the fact that the notion of composition does not
  translate well into physics:

•   Of what are quasiparticles composed?
•   Are particles composed of quantum fields?
•   What composes a black hole?
    1. Theory Change as a
  Motivation for Structuralism
• Antirealism: science saves the phenomena
• Realism: science describes the furniture of
  the world
• Structural Realism: science tells us about the
  structure of the world - more than merely
  saving the phenomena but less than full
  ontological commitment
  – Example: even the existence of central theoretical
    entities is necessary for more than empirical
    adequacy.
    The Theory of Phlogiston
• Burning is a process in which a principle of
  combustion is given off by the fuel and enters
  the air.
     The Theory of Phlogiston
• Burning is a process in which a principle of
  combustion is given off by the fuel and enters the air.
• All flammable substances are supposed to contain
  phlogiston and it is what all metals have in common.
     The Theory of Phlogiston
• Burning is a process in which a principle of
  combustion is given off by the fuel and enters the air.
• All flammable substances are supposed to contain
  phlogiston and it is what all metals have in common.
• There is no such substance and ordinary combustion
  is the addition of oxygen to something and not the
  emission of something by the fuel.
     The Theory of Phlogiston
• Burning is a process in which a principle of combustion is given
  off by the fuel and enters the air.
• All flammable substances are supposed to contain phlogiston
  and it is what all metals have in common.
• There is no such substance and ordinary combustion is the
  addition of oxygen to something and not the emission of
  something by the fuel.
• So it seems obvious that phlogiston theory must be bad science.
            The Theory of Phlogiston (heyday 1700-1790)



• Becher (1635-1682) proposed combustible earth (as one of
  three earths composing ordinary substances).
               The Theory of Phlogiston (heyday 1700-1790)

•   Becher (1635-1682) proposed combustible earth (as one of three
    earths composing ordinary substances).
•   Stahl (1660-1734) proposed phlogiston in 1697 (also year the world‘s
    first heat engine was built): parallels between metals heated in air
    (calcination) and ordinary combustion – creation of dust and light often
    given off, lots of air needed. Phlogiston given off in combustion - flames
               The Theory of Phlogiston (heyday 1700-1790)

•   Becher (1635-1682) proposed combustible earth (as one of three
    earths composing ordinary substances).
•   Stahl (1660-1734) proposed phlogiston in 1697 (also year the world‘s
    first heat engine was built): parallels between metals heated in air
    (calcination) and ordinary combustion – creation of dust and light often
    given off, lots of air needed. Phlogiston given off in combustion - flames
•   Wood turns to ash when burnt (phlogiston must therefore have mass).
•   Iron rusts to calx also giving off phlogiston.
•   Charcoal combusts almost completely so charcoal is very nearly pure
    phlogiston.
               The Theory of Phlogiston (heyday 1700-1790)

•   Becher (1635-1682) proposed combustible earth (as one of three
    earths composing ordinary substances).
•   Stahl (1660-1734) proposed phlogiston in 1697 (also year the world‘s
    first heat engine was built): parallels between metals heated in air
    (calcination) and ordinary combustion – creation of dust and light often
    given off, lots of air needed. Phlogiston given off in combustion - flames
•   Wood turns to ash when burnt (phlogiston must therefore have mass).
•   Iron rusts to calx also giving off phlogiston.
•   Charcoal combusts almost completely so charcoal is very nearly pure
    phlogiston.
•   Phlogiston was supposed to have a metallic quality. Metal calx burnt in
    charcoal becomes ordinary metal - adding phlogiston adds the metallic
    quality to the true form (calx) of the metal (practical application to
    copper mining).
                 The Theory of Phlogiston (heyday 1700-1790)

•   Becher (1635-1682) proposed combustible earth (as one of three earths
    composing ordinary substances).
•   Stahl (1660-1734) proposed phlogiston in 1697 (also year the world‘s first heat
    engine was built): parallels between metals heated in air (calcination) and
    ordinary combustion – creation of dust and light often given off, lots of air
    needed. Phlogiston given off in combustion - flames
•   Wood turns to ash when burnt (phlogiston must therefore have mass).
•   Iron rusts to calx also giving off phlogiston.
•   Charcoal combusts almost completely so charcoal is very nearly pure
    phlogiston.
•   Phlogiston was supposed to have a metallic quality. Metal calx burnt in charcoal
    becomes ordinary metal - adding phlogiston adds the metallic quality to the true
    form (calx) of the metal (practical application to copper mining).
•   When something burns in a sealed container it uses up the oxygen in the air
    until eventually the fire goes out. This was explained in terms of the saturation of
    the air with phlogiston.
•   Combustion, respiration and calcification are all the same kind of reaction
    (oxidisation). (Animals in a sealed chamber phlogisticate the air (Boyle).)
                      The Theory of Phlogiston


Big Problem

• Since Rey (1630) it was known that the calx of a metal could be
  heavier than its metallic form.

• Some Stahlians posited negative weight for metallic phlogiston
  but most believed that impurities caused the weight increase.
              Priestley (1733-1804)

• Plants dephlogisticate the air (cycle between plants
  and animals).
• Air without any phlogiston is air whose potential to be
  burnt is maximal.
• Dephlogisticated air by heating a calx (red mercury)
  (1774)
• Scheele (1742-1786): ‗fire air‘ (1771-2, published
  1777)
• There is a clear sense in which the dephlogisticated
  air that Priestley describes breathing is oxygen.
                            Priestley (1733-1804)

•   Plants dephlogisticate the air (cycle between plants and animals).
•   Air without any phlogiston is air whose potential to be burnt is maximal.
•   Dephlogisticated air by heating a calx (red mercury) (Priestley 1774)
•   Scheele (1742-1786): ‗fire air‘ (1771-2, published 1777)
•   There is a clear sense in which the dephlogisticated air that Priestley
    describes breathing is oxygen.
•   Phlogisticated air is air saturated with phlogiston.
•   Inflammable air [hydrogen (Cavendish 1766)] is pure phlogiston not
    charcoal according to Cavendish.
•   Priestley burned metal oxide in inflammable air to make pure metal
    (and water) - reduction inverse of oxidisation.
•   But inflammable air is obviously not just ordinary air with phlogiston in
    higher concentration, since ordinary air becomes saturated with
    phlogiston during combustion and eventually the fire goes out.
•   Some of the phlogisticated air dissolves in water (carbon dioxide) and
    some does not (mostly nitrogen). Neither supports ordinary combustion
    (like Oxygen) or reduction (like hydrogen).
              Lavoiser (1743-1794)

• Oxygen (dephlogisticated air) and hydrogen
  (phlogisticated air) found in compound ordinary air
  and make up water.
• Burning, respiration and rusting of iron are all
  oxidisation.
• But he also thought all acids contain oxygen and that
  oxygen was a principle not an element.
                 Realists on Phlogiston

• Among philosophers ‗phlogiston‘ is a prime example
  of a non-referring theoretical term.

  ―phlogiston refers to nothing‖ (Psillos)

  ‗Phlogiston‘ is a counterexample to the simple causal
  theory since then it would refer to oxygen (whatever
  is involved in combustion) (Bird)
                                   Phlogiston‘s Success

•   Explains loss of weight of wood, coal and ordinary substance when burnt.
•   Charcoal leaves hardly any ash because it is almost pure phlogiston.
•   Air saturated with phlogiston cannot support respiration.
•   Metal + heat (in air) = calx [metal oxide] + phlogisticated air [de-oxygenated air]
•   Calx + charcoal (source of phlogiston) = metal (+ fixed air [carbon dioxide (Joseph Black
    (1728-1799) 1754)])
•   So Metal = calx + phlogiston (explaining what metals have in common)
•   Charcoal = calx (fixed air) + phlogiston
•   Metal + acid = salt + inflammable air (note Lavoisier thought acids had to contain oxygen)
•   Metal + water = calx + inflammable air
•   (Water = inflammable air [hydrogen] + dephlogisticated air [oxygen])
•   Dephlogisticated marine acid (Scheele) = chlorine (Davy).
•   novel prediction: heat calx in inflammable air to get pure metal
•   novel prediction of new acids by Scheele (formic acid, lactic acid)
•   Animals and plants have opposite effects on the air - the former phlogisticate and the latter
    dephlogisticate
•   Metals are alike (lost by intermediary science between Priestley and electronic chemistry).
•   Phlogistication and dephlogistication are inverse chemical reactions (reduction and
    oxygenation)
• ‗phlogistication‘ and ‗dephlogistication‘ can be
  regarded as referring to the processes of
  oxidation and reduction, where these are
  understood in the general sense of the
  formation of an ionic bond with an
  electronegative substance, and the regaining
  of electrons respectively.
• ‗phlogistication‘ and ‗dephlogistication‘ can be
  regarded as referring to the processes of oxidation
  and reduction, where these are understood in the
  general sense of the formation of an ionic bond with
  an electronegative substance, and the regaining of
  electrons respectively.
• If the oxidising agent is oxygen, and the oxidised
  compound is a source of carbon then the product is
  carbon dioxide i.e. fixed air. (combustion of fossil
  fuels)
• If the oxidising agent is an acid, then hydrogen is
  emitted.
• ‗phlogistication‘ and ‗dephlogistication‘ can be
  regarded as referring to the processes of oxidation
  and reduction, where these are understood in the
  general sense of the formation of an ionic bond with
  an electronegative substance, and the regaining of
  electrons respectively.
• If the oxidising agent is oxygen, and the oxidised
  compound is a source of carbon then the product is
  carbon dioxide i.e. fixed air. If the oxidising agent is
  an acid, then hydrogen is emitted.
• We could go further and allow that ‗phlogiston rich‘
  and ‗phlogiston deficient‘ refer too, namely to strongly
  electro-negative and electro-positive molecules
  respectively.
• One could even argue that ‗phlogiston‘ refers to
  electrons in the outer orbital of an atom.
 Forgotten Wisdom: Whewell, History of
         the Inductive Sciences
• ―But we must not forget how natural it was to
  suppose that some part of a body was
  destroyed or removed by combustion…It
  would be easy to show, from the writings of
  phlogistic chemists, what important and
  extensive truths their theory enabled them to
  express simply and clearly.‖
• Combustion, respiration and calcination of
  metals are all the same kind of reaction and
  there is an inverse kind of reaction too.
                         Structural Realism

•   John Worrall (1989) introduced structural realism (although he
    attributes its original formulation to Poincaré). Using the case of the
    transition in nineteenth century optics from Fresnel's elastic solid ether
    theory to Maxwell's theory of the electromagnetic field, Worrall argues
    that:

    ―There was an important element of continuity in the shift from Fresnel
    to Maxwell – and this was much more than a simple question of
    carrying over the successful empirical content into the new theory. At
    the same time it was rather less than a carrying over of the full
    theoretical content or full theoretical mechanisms (even in approximate
    form) ... There was continuity or accumulation in the shift, but the
    continuity is one of form or structure, not of content (1989, 117).
                 More Structural Realism

• Instructive historical examples:

 The transition from Fresnel‘s ether theory of light to Maxwell‘s
  electromagnetic field theory.
 The transition from Galilean relativity to Lorentz invariance.
 The transition from classical mechanics to quantum mechanics.
 The transition from Newtonian gravitation to General Relativity.
                 Modality
• We have been very focused on the
  composition of wholes by parts and have not
  addressed the key issue of the status of
  putative causal claims at different levels.
• More generally, I consider modality to be a
  central issue for the philosophy of physics.
  (Counterfactual definiteness + Locality is
  sufficient to prove Bell‘s theorem (cf. Tomasz
  Bigaj in SHPMP).)
                Modality
• Realism: physics tells us about
  causation, the laws of nature and deep
  metaphysics

• Antirealism: physics gives maximally
  general descriptions of regularities in
  the phenomena
                     Modality
• Realism: physics tells us about causation, the
  laws of nature and deep metaphysics

• Antirealism: physics gives maximally general
  descriptions of regularities in the phenomena

o Example: the speed limit of light speed - is it merely a
  generalization that is true or does it have some kind
  of necessary status?
                     Modality
• Realism: physics tells us about causation, the
  laws of nature and deep metaphysics

• Antirealism: physics gives maximally general
  descriptions of regularities in the phenomena

o Example: the speed limit of light speed - is it merely a
  generalization that is true or does it have some kind
  of necessary status?

o Example: the laws and the constants and the fine-
  tuning argument
     Is Physics Special and is
 fundamental physics special with
   respect to the rest of physics?

―In science there is only physics; all the rest is
   stamp collecting.‖
                         Ernest Rutherford
   The Incompleteness of the
       Special Sciences
• In all the special sciences it is acceptable to
  invoke entities and processes from more
  fundamental sciences in explanations.
• For example, the economy may be affected
  by the weather, living systems may be
  affected by radiation, chemical reactions may
  be affected by magnetic fields, and so on.
• There is a fundamental asymmetry between
  physics and the special sciences.
The Completeness of Physics
• Fundamental physics aspires to a kind of
  completeness in so far as it is never permitted
  to invoke entities or processes from the
  special sciences in an explanation of the
  behaviour of the the fundamentally physical.
• Physics is analytically complete since it is the
  only science that cannot be left incomplete.
            Fundamental Physics

• Measurements at all scales and at all
  locations in spacetime are potential
  falsifications or confirmations of fundamental
  physics.
• This is not true of any other science.
• Fundamental physics may not exist other
  than as a limiting ideal (if there is no
  fundamental level).
• (Many parts of physics are special sciences.)
    The Primacy of Physics Constraint (PPC)

•    Naturalists ought only to accept a form of physicalism that is motivated
     by reflection on the history of science and the nature and practice of
     contemporary science. Ladyman and Ross argue that this justifies
     nothing more than the PPC (methodological physicalism):

     ―Special science hypotheses that conflict with fundamental physics, or
     such consensus as there is in fundamental physics, should be rejected
     for that reason alone. Fundamental physical hypotheses are not
     symmetrically hostage to the conclusions of the special sciences.‖
     (2007, 44)

•    This leaves it open to the naturalist to believe both that the entities
     posited by the special sciences exist, and that the causal relations
     posited by them are genuine.
2. Structuralism and the Part-
        Whole relation
• The natural numbers are often said to
  ontologically depend on each other and the
  relations among them - so the parts depend
  on the whole.
• Cf. the identity and individuality of spacetime
  points depends on the metric field and hence
  again the parts depend on the whole.
• Structuralism: less than ontological
  commitment to the dressing theory is
  given; more than relations among the
  phenomena.
      Objects and Individuals

• What does it take to be an object?
• What does it take to be an individual?

• Quasi-particles, Bose Einstein Condensates, Cooper
  pairs, entangled photon pairs, quantum fields…
• Do they ‗exist‘ in the same sense as tables and
  chairs?
            Individuation
• PII and weak discernibility - structures
  admitting a non-trivial automorphism -
  complex plane, fermions in the singlet
  state (Michal)
• purely relational individuation
• an asymmetric graph of order 6: pure
  relations can give rise to absolute
  discernibility
                    Quasi-Particles
•   Bipolaron       a bound pair of two polarons
•   Chargon         a quasiparticle produced as a result of electron spin-charge separation
•   Configuron      an elementary configurational excitation in an amorphous material which
                                 involves breaking of a chemical bond
•   Electron hole   a lack of electron in a valence band
•   Exciton         a bound state of an electron and a hole
•   Fracton         a collective quantized vibration on a substrate with a fractal structure.
•   Holon           a quasi-particle resulting as a result of electron spin-charge separation
•   Libron          a quasiparticle associated with the librational motion of molecules in a
                                 molecular crystal
•   Magnon          a coherent excitation of electron spins in a material
•   Phason          vibrational modes in a quasicrystal associated with atomic
                                 rearrangements
•   Phonon          vibrational modes in a crystal lattice associated with atomic shifts
•   Plasmon         a coherent excitation of a plasma
•   Polaron         a moving charged quasiparticle that is surrounded by ions in a material
•   Polariton       a mixture of photon with other quasiparticles
•   Roton           elementary excitation in superfluid Helium-4
•   Soliton         a self-reinforcing solitary excitation wave
•   Spinon          a quasiparticle produced as a result of electron spin-charge separation
         3. Real Patterns


• macroscopic objects as relatively stable
  and enduring patterns that emerge
  within the structure of the quantum state
  of the world.
• On such a view, the world need not
  form a compositional hierarchy, with or
  without ultimate parts.
            Special Science Ontology
• In science one is only interested in recovering the statistical
  properties of low-level entities when tracking high level ones.
• Coarse-graining and approximation are necessary for special
  science ontologies to emerge. This explains why even token
  identities do not obtain between say a cat and its constituent
  atoms.
• In the special sciences one is usually interested in ‗universal‘
  forms of behaviour, where ‗universal‘ means independent of
  microphysical or lower level constitution. The identification of
  universality and the appropriate descriptive categories for
  tracking it is one of the principle tasks of the special sciences.
• The scale relativity of ontology (Ladyman and Ross)
• The renormalization group view of the world (Sokal and
  Bricmont): the renormalization group describes transformations
  that allow the number of degrees of freedom in the Hamiltonian
  of a system to be massively reduced while still recovering the
  critical behaviour of the system.
                     Complexity
• The special sciences are possible because the world is to some
  extent algorithmically compressible. At certain levels of
  description it is possible to use much less information to predict
  the behaviour of systems described in an approximate and
  probabilistic way, than would be needed to describe their
  microstates.
• For example, Kepler‘s laws, the ideal gas laws, the Hardy–
  Weinberg law,… In fact all laws in the special sciences are like
  this. The special sciences rely upon reduction in the degrees of
  freedom of the system.
• There are real patterns in the world that are only visible at the
  right scales of resolution and degrees of approximation. If you
  don‘t see them you are missing something about reality and that
  is good enough to allow us to say that the objects, properties
  and processes described by the special sciences are real.
Computational Approaches to
       Emergence
• between order and randomness
• logical depth, thermodynamic depth,
  statistical complexity, information
  theoretic entropy, algorithmic
  complexity,…
• complex systems involve hierarchical
  organisation.
                Real Patterns
• Daniel Dennett‘s notion of ‗real pattern‘ is a
  computational one.
• The idea is based on the compression of data and
  the reduction of information processing made
  possible by a high level description of a system that
  could in principle be described at a fine-grained level
  but at a much greater computational cost.
•   John Conway‘s ‗Game of Life‘ is based on a simple implementation of
    cellular automata that makes a particular range of stable dynamic
    attractors highly salient to people.
•   A person using the system naturally book-keeps its state sequences by
    reference to a typology of ‗emergent‘ objects—‗gliders‘, ‗eaters‘,
    ‗spaceships‘, etc.—that have only virtual persistence. (That is, two
    successive instances of ‗the same‘ glider share only structure, and
    common participation in structures larger than themselves.
•   A glider is clearly mereologically composed of a small number of
    illuminated cells. However, its successive instances are composed of
    different cells, and successive instances a few steps apart have no
    cells in common.)
•   Once this descriptive stance is adopted towards Life, almost all users
    spontaneously track the dynamics in terms of causal interactions
    among instances of these types—for example, a glider will be caused
    to disappear through interacting with an eater. That is, Life users
    naturally begin logging causal generalizations about the types of virtual
    objects, and thereby seem to commit themselves to their objective
    existence.

(All the above paragraphs are taken from Ladyman and Ross (2007), chapter 4.)
    – One should be cautious in using the Game of Life as a
      metaphysical model of the universe.
    – It is useful for the purposes to which Dennett puts it,
      because it shows how patterns can emerge at grains of
      analysis coarser than the grain at which what is analogous to
      the fundamental microphysical level is studied, even when
      all causal processes governing the latter are non-complex,
      known, measurable, and deterministic. Life is thus a good
      antidote to romantic interpretations of emergence.
    – However, because in Life there is an unambiguous
      fundamental level composed of the aggregation of a finite
      number of little things, and because no higher-level object
      types cross-classify the dimensions of any models of the
      game relative to classifications in terms of cells, Life differs
      greatly from the universe with respect to the kinds of
      reductionism sustainable in it. Life admits of complete
      decomposition; the universe might not.

(All the above paragraphs are taken from Ladyman and Ross (2007), chapter 4.)
      Definition of Real Patterns
               (Ladyman and Ross, 2007, chapter 3

       To be is to be a real pattern; and a pattern is real iff
I.     it is projectible under at least one physically possible
       perspective; and,
II.    it encodes information about at least one structure of events
       or entities S where that encoding is more efficient, in
       information-theoretic terms, than the bit-map encoding of S,
       and where for at least one of the physically possible
       perspectives under which the pattern is projectible, there
       exists an aspect of S that cannot be tracked unless the
       encoding is recovered from the perspective in question.
•   According to RP, the utility of the intentional stance is a special case of
    the utility of scale-relative perspectives in general in science, and
    expresses a fact about the way in which reality is organized—that is to
    say, a metaphysical fact. The fact in question is what we (but not
    Dennett) call the scale relativity of ontology.
•   Scale relativity of epistemology isn‘t controversial. To borrow an
    example from Wallace (2001), if you want to predict what a hungry tiger
    will do when confronted with a deer, you should study whole
    behavioural patterns of whole tigers, not individual tiger cells or
    molecules. It is clearly motivated by any thesis to the effect that models
    of complex systems are scientifically useful.
(All the above paragraphs are taken from Ladyman and Ross (2007), chapter 4.)
•   trade offs between scope, accuracy and simplicity
• Real patterns are preserved on theory
  change - cf. Butterfield on the Krebs
  cycle.
• Dennett‘s paper is notoriously unclear
  about whether ‗real patterns‘ should be
  regarded as real or as useful fictions.
• realism versus pragmatism -
  metaphysics versus epistemology
• Conservative metaphysicians would complain, the eater is a
  redundant causal factor, since the program underlying Life,
  which in its declarative representation quantifies only over cells,
  is strictly deterministic. We are reminded that an eater or a glider
  is, at any given time, ‗made of‘ cells and nothing else. Then we
  are invited to agree that a thing cannot have causal efficacy
  over and above the summed causal capacities of the parts with
  which it is allegedly identical. The result is supposed to be
  reductionism, and instrumentalism about gliders and eaters.

(The above paragraph is from Ladyman and Ross (2007), chapter 4.)
• Real patterns are defined modally.
• They are there to be discovered.
• David Wallace advocates what he calls a functionalist
  account of ontology based on the notion of real
  patterns in his elucidation of the Everettian
  interpretation of quantum mechanics.
• His ontology is two-tier in that only higher-order
  entities such as cats and tables are understood in
  terms of real patterns, whereas the wavefunction or
  whatever else proves to be fundamental in physics is
  understood in categorical rather than functional
  terms.
• On the other hand, James Ladyman and Don
  Ross (2007) advocate a real patterns account
  of ontology across the board.
• All real patterns are real but there is an
  asymmetric relation among them.
• The relation is not composition since
  emergent structure is not reducible to the
  sum of the parts - no building blocks (Healey)
• Real patterns theory can be developed in
  terms of the dynamics of phase spaces rather
  than in computational terms. (Jenann Ismael
  suggested this.)
• Reducing the number of degrees of freedom
  by finding ‗objects‘.
• There are synchronic patterns too of course
  but they could be represented in terms of
  laws of co-existence.

				
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