the dependence of objects on structure: tailoring our metaphysics to fit the physics
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The Dependence of Objects on Structure: Tailoring our Metaphysics to Fit the Physics. Steven French Dept. of Philosophy University of Leeds. Acknowledgments. Thanks to Jos and Richard for organising such a congenial workshop and to the Lorentz Centre for funding, facilities, food âŚ. - PowerPoint PPT PresentationTRANSCRIPT
The Dependence of Objects on Structure: Tailoring our Metaphysics to
Fit the Physics
Steven FrenchDept. of PhilosophyUniversity of Leeds
Acknowledgments
⢠Thanks to Jos and Richard for organising such a congenial workshop and to the Lorentz Centre for funding, facilities, food âŚ.
⢠Thanks also to James Ladyman, Angelo Cei, Terry Horgan, Kerry McKenzie, Laurie Paul, David Wallace and all⌠for helpful discussions.
Part, Whole and Composition
⢠General Composition Question:What is composition?
â Special Composition QuestionIn which cases is it true of certain objects that they compose something?
â Inverse Composition QuestionIn which cases is it true of an object that there are objects that compose it?
(P. Inwagen, Material Beings, Ithaca NY: Cornell University Press, 1990, pp. 39-48 )
Part, Whole and Composition: Double Standards
⢠Double Standardsâ answer to GCQ (but not SCQ or ICQ) must be a conceptual
truth⢠e.g. xs compose y iff no two of the xs occupy overlapping regions of
space and y occupies the sum of the regions of space occupied by the xs.
⢠fails because counter-example is conceivable⢠why adopt such âhighâ standards? (K. Hawley, âPrinciples of Composition and Criteria of Identityâ, Australasian Journal
of Philosophy, 84.4 (2006), 481-93)
⢠revelatory of problems with metaphysics?â cf. Hacking: âblandâ metaphysical assertion not enough(Hacking, I. (1975), âThe Identity of Indiscerniblesâ, Journal of Philosophy, 72, pp.
249-256)
Part, Whole and Composition: Two Desiderata
⢠Two Desiderata (T. Horgan and M. Potrc, Austere Realism, MIT Press 2008, p. 18)
â Unitary answers⢠answers to the above questions should be general and
systematic
â Mesh with common sense and/or physics⢠answers should yield an ontology that conforms
reasonably well to pre-theoretic and scientific beliefs
â Unitarity trumps Meshing⢠further problem for metaphysics?
Part, Whole and Composition: Double Standards and Unitarity
⢠Double standards and unitary answers:â Hawley: cf criteria of identity⢠just as criteria of identity can differ for different kinds of
thing, so can answers to the GCQ
â Ladyman and Ross (Everything Must Go, OUP 2007, p.21)⢠different scientific domains, different composition
relations
Part, Whole and Composition: Double Standards and Unitarity
âIt [the general composition relation] is supposed to be the relation that holds between the parts of any whole but the wholes mentioned above are hugely disparate and the composition relations studied by the special sciences are sui generis. We have no reason to believe that an abstract composition relation is anything other than an entrenched philosophical fetish.â (L&R p. 21)
Part, Whole and Composition
⢠Meshingâ Satisfy naturalist tendencies (cf Ladyman and Rossâs PNC)â Problem: underdetermination of metaphysics by physics
⢠e.g. identity and QM (S.French & D. Krause, Identity in Physics, OUP 2006)
â Example of âmetaphysical humilityâ⢠extensive array of metaphysical âfactsâ about which we can have
no knowledge
â Response: be less humble⢠rule out such âfactsâ (esp. those problematic for realist)
(Modest but Not So Humble) Structuralism
⢠Shift in ontological focusâ objects structures
(see S. French and J. Ladyman, âIn Defence of Ontic Structural Realismâ, forthcoming in A. Bokulich and P. Bokulich, Scientific Structuralism, Boston Studies in the Philosophy of Science; Springer)
⢠Physics and Philosophy in the 20th C.â Duhem, PoincarĂŠ, Cassirer, Russell, Eddington, Born ⌠⢠reconceptualisation of physical objects via structure⢠characterisation of structure via group theory (
objectivity)
Two Forms
⢠ESR: All that we know is structure⢠Agnosticism about âobjectsâ humility
⢠(J. Worrall, 'Structural Realism: The Best of Both Worlds?', Dialectica 43 (1989) pp. 99-124)
⢠OSR: All that there is, is structure⢠(J. Ladyman, 'What is Structural Realism?', Studies in History and
Philosophy of Science, 29 (1998) pp. 409-24; S. French, âStructure as a Weapon of the Realistâ, Proceedings of the Aristotelian Society 106 (2006) pp. 170-187.J. Ladyman et. al., Everything Must Go, OUP 2007)
Two Variants
⢠Eliminativist OSRâ structure, no objects
⢠French, Ladyman
⢠Non-Eliminativist OSRâ structure + âthinâ objects
⢠identity given contextually⢠e.g. relationally via âweak discernibilityâ (fermions; bosons
contentious)⢠Ladyman, Saunders
(Muller, F., and M. Seevinck (2009), âDiscerning Elementary Particlesâ, Philosophy of Science 76: 179â200.; Ladyman, J. and Bigaj, T. (2010), âThe Principle of the Identity of Indiscernibles and Quantum Mechanicsâ, Philosophy of Science 77: 117â136)
Issues
⢠What is structure?
⢠What is the relationship between structure and (putative) objects?
What is structure: laws and symmetry
⢠Structuralist methodology:â theories present laws, symmetries âŚâ laws: relations between properties⢠identity of properties given by nomic role
â resist further step of positing (metaphysically robust)objects
â putative objects (eg particles) reconceptualised andcharacterised via symmetry groups
(E. Castellani, 'Quantum Mechanics, Objects and Objectivity', in C. Garola and
A. Rossi, The Foundations of Quantum Mechanics â Historical Analysis and
Open Questions, pp. 105-114, Kluwer, 1993)
What is structure: laws and symmetry
⢠Objects (metaphysically) dependent on structures (role of symmetries)
⢠Properties (metaphysically) dependent on laws (inc. conservation laws)
⢠Structure (putative) objects and properties⢠âTop downâ metaphysics rather than âbottom upâ
(see A. Cei and S. French, âGetting Away from Governance: A Structuralist Approach to Laws and Symmetriesâ)
What is the relationship between structure and objects: tables and particles
⢠Eddington and his two tablesâ Stebbing: object of scientific description â âtableââ Thomasson: â⌠scientific theories ⌠do not use sortals such as
âtableâ, and if science and common sense are using sortals of different categories, the âthingsâ picked out by the two descriptions cannot be identical.â (A. Thomasson, Ordinary Objects, OUP 2997, p. 142)
No conflict inflationary ontology
What is the relationship between structure and objects: tables and particles
⢠Response: eliminativism (about ordinary objects)
⢠Dilemma: Tables donât existbut
âTables existâ appears to be true!
What is the relationship between structure and objects: tables and particles
⢠Option 1: revise semanticsâ adopt error theoretic approachâ âTables existâ is simply falseâ but can still pragmatically use such sentencesâ cf. mathematics
⢠Option 2: revise truth and/or ontologyâ Account for appearance in terms of:
derivative existence, truth as indirect correspondence, truthmakers âŚ
What is the relationship between structure and objects: tables and particles
⢠(Intuition) Derivative existence:â âTables existâ is true but the sense of âexistâ is derivativeâ cf. Eddington: âTables exist âŚâ = unfinished sentence
⢠cf. quasi-particles ⌠(B. Falkenburg, Particle Metaphysics (The Frontiers Collection), Berlin: Springer 2007, esp. pp. 243-46)
â What finishes it is structure structural conception of existence⢠What about â(Fundamental) structure exists âŚâ?⢠Nothing further added to knowledge by saying âand the physical
universe/world structure exists.â(see S. French, 'Scribbling on the Blank Sheet: Eddington's Structuralist
Conception of Objects', Studies in History and Philosophy of Modern Physics 34, pp. 227-259, 2003.)
What is the relationship between structure and objects: tables and particles
⢠Tweak Truth:
âNumerous statements and thought-contents involving posits of common sense and science are true, even though the correct ontology does not include these posits. âŚ
Truth for such statements and thought contents is indirect correspondence.â (T. Horgan and M. Potrc, Austere Realism, MIT Press 2008, p. 3)
(+ impossibility of ontological vagueness minimalist ontology: one concrete particular (the âblobjectâ) that manifests considerable spatio-temporal structural complexity and local variability)
What is the relationship between structure and objects: tables and particles
⢠âThere are tablesâ is true but there are no tablesâ âThere are tables is true, under the contextually
operative standards governing common usageâ âThere are no tablesâ is true, under the much rarer
âdirect correspondenceâ semantic standardsâ Worry: context dependence relativism (of
content)?
What is the relationship between structure and objects: tables and particles
⢠Try Truthmakersâ Retain truth and direct correspondence but reconsider
what makes statements true
â Armstrong: the truthmaker for âx existsâ is (always) x
â Cameron: the truthmaker for âx existsâ may not be x
(R. Cameron, âTruthmakers and ontological commitment: or how todeal with complex objects and mathematical ontology without getting into
troubleâ, Philosophical Studies (2008) 140:1â18)
What is the relationship between structure and objects: tables and particles
⢠âTables existâ is true but deny ontological commitment to tablesâ âTables existâ made true by âsimplesâ (arranged table-
wise)â retains literal (non-contextual) truth of sentencesâ captures intuition that complex objects exist, in a
derivative sense, but donât really existâ what really exist are the âsimplesâ
⢠Worry: simples? (cue meerkat) ⢠release from s-t constraint
What is the relationship between structure and objects: particles and structure
⢠Particles?â QFT concernsâ âParticles existâŚâ (expressed in âpractical language of
elementary particle dynamicsâ) in structural sense of existence; i.e. particles exist as aspects of structure
â âParticles existâ is (contextually) true in indirect correspondence sense; i.e. there are no particles (as objects), just structure or aspects thereof
â âParticles existâ is (literally) true but there are no particles as objects; i.e. truthmakers = structure or aspects thereof (arranged particle-like)
What is the relationship between structure and objects: particles and structure
⢠Simples = particles-as-objects?â No: recall motivations for structural realism
⢠Simples = quantum fields, s-t structureâŚâ monadic structuralism: there is only the âworld structureâ
⢠cf. Horgan and Potrcâs âblobjectivismâ⢠complexity recovered via âmanners of instantiationâ
â pluralistic structuralism: inter-related structures at fundamental level
â hierarchical structuralism: inter-related structures between levels ⢠instantiation? dependence??
What is the relationship between structure and objects: fusion?
⢠Stick with truth, resist truthmakers:⢠Mereological bundle theoryâ Key move: âour knee-jerk way of thinking about the
things physicists describe as âobjectsâ or âparticlesâ as little material-like hunks of stuff is fundamentally mistaken.â
(L.A. Paul, âParthood and Individuation in a One-Category Ontologyâ forthcoming)
⢠World not built from bottom up, âspatio-temporal hunk by spatiotemporal hunkâ
What is the relationship between structure and objects: fusion?
⢠Only category: propertiesâ âobjectsâ = bundles of propertiesâ bundling = qualitative compositionâ qualitative composition is restricted âMy personal preference is for a contingent, purely
qualitative mereological bundle theory where spacetime, as well as everything else there is, is constructed from fusions of properties.â
â Properties = polyadic structure⢠Worry: overlapping parts?
â role of contingent constraints
What is the relationship between structure and objects: fusion?
⢠Bringing together the blob and the bundle:â blob = world structureâ âglobalâ bundling of polyadic properties structureâ âlocalâ bundling of polyadic properties âobjectsââ costs: manners, parts etc.â keep costs down: look to the physics⢠fundamental: dependence
What is the relationship between structure and objects: dependence?
⢠laws properties⢠group structure fundamental objects &
compositesâ e.g. development of the quark model from the
SU(3) approach â settling the structure effectively settles the
question of which hadrons exist (McKenzie, forthcoming)
â group theory as âanalysisâ of composition
What is the relationship between structure and objects: dependence?
⢠(ODS) Fundamental physical âobjectsâ depend on the relevant structure.(cf. Ă. Linnebo, (2008), âStructuralism and the notion of
dependenceâ Philosophical Quarterly, 58, 59â79)
⢠Dependence can take various forms(cf. E.J. Lowe, E. J., âOntological dependenceâ, Stanford Encyclopaedia of philosophy, (2005). http://plato.stanford.edu/entries/dependence-ontological/)
(See: S. French, âThe interdependence of structure, objects and dependenceâ forthcoming in Synthese)
What is the relationship between structure and objects: dependence
⢠Identity Dependence:⢠(ID) âobjectsâ depend for their existence on
structure =df necessarily, the identity of such objects is dependent on the structure
⢠Fits with Non-Eliminativist OSR (and Stachel on space-time)â Worry: if all properties + identity of bearers of
relations cashed out in terms of latter, then what is doing the bearing?
What is the relationship between structure and objects: dependence
⢠Constitutive Dependence:⢠(CD) âobjectsâ depend for their existence on
structure =df necessarily, the constitutive nature/ âessenceâ of such objects is dependent on the structure
⢠captures intuition behind derivative existence⢠Fits with Eliminativist OSR
Back to Composition
⢠Recall GCQ: what is composition?â van Inwagen: The xs compose y iff no two of the xs occupy
overlapping regions of space and y occupies the sum of the regions of space occupied by the xs.
â Donât need to go to distant possible world to have doubts about this
⢠Hawley: different answers for different things⢠But: cf identity criteria
â underdetermination abandon identity criteria (ElimOSR)â structuralism abandon (general) object based
composition
Simples, Blobs and Structures⢠SCQ as constraint: ârightâ ontology must provide systematic and general answer to
SCQ: When do several distinct objects compose an object?
â derivative existence: composite objects âexistâ, but not really⢠Answer to SCQ: never (no composite objects)
â blobjectivism: only one concrete particular⢠no composite objects⢠Answer to SCQ: never (only one real object)
â truth-makers: many simples⢠(putative) composite objects are âontological free lunchâ (Cameron,
Truth-Makers and Ontological Commitment)⢠Answer to SCQ: never (no collection of objects ever composes)
Simples, Blobs and Structures
â ElimOSR: no objects, composite or composing⢠Answer to SCQ: never (no composing objects)⢠monadic structuralism sim. to blob⢠pluralistic structuralism sim. to simples
â Non-ElimOSR: âthinâ objects⢠Answer to SCQ: never (objects too thin to compose)
Science, metaphysics and the philosophy of science
⢠Stating the obvious:
â physics-lite metaphysics runs the risk of floating free (L&R p. 9)
â metaphysics-lite realism runs the risk of incomprehension
Science, metaphysics and the philosophy of science
⢠Suggesting the less obvious (perhaps):â Humility allows insulation of metaphysics from
physics (cf. Ladyman and Ross p. 22, on Merricks)
⢠e.g. are simples individuals or not?⢠physics canât answer (underdetermination)
â Lower standards and suppress humility to accommodate physics⢠reduce no. of unknowable metaphysical facts by
reducing basis for such facts (e.g. objects)
Science, metaphysics and the philosophy of science
⢠Cut our metaphysical cloth to fit the physics, with the philosopher of science as tailor!