Humana_Mente 13 Physics and Metaphysics

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ISSUE 13 - A PRIL 2010

Physics and Metaphysics

EDITED BY C LAUDIO C ALOSI


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EDITORIALMANAGER: ALBERTOPERUZZI- UNIVERSITY OFFLORENCEDIRECTOR: DUCCIOMANETTI- UNIVERSITY OFFLORENCE

VICEDIRECTOR: SILVANOZIPOLICAIANI- UNIVERSITY OFMILAN

INTERNATIONALEDITORIALBOARD

JOHN BELL- UNIVERSITY OFWESTERNONTARIO

GIOVANNIBONIOLO- INSTITUTE OFMOLECULARONCOLOGYFOUNDATION

MARIALUISADALLACHIARA- UNIVERSITY OFFLORENCE

DIMITRID'ANDREA- UNIVERSITY OFFLORENCE

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MASSIMOINGUSCIO- EUROPEANLABORATORY FORNON-LINEARSPECTROSCOPY

GEORGELAKOFF- UNIVERSITY OFCALIFORNIA, BERKELEY

PAOLOPARRINI- UNIVERSITY OFFLORENCE

JEANPETITOT- CREA, CENTRE DERECHERCHE ENPISTMOLOGIEAPPLIQUEPAOLOROSSIMONTI- ACCADEMIANAZIONALE DEILINCEI

CORRADOSINIGAGLIA- UNIVERSITY OFMILAN

CONSULTINGEDITORS

CARLOGABBANI- UNIVERSITY OFFLORENCE

ROBERTALANFREDINI- UNIVERSITY OFFLORENCE

MARCOSALUCCI- UNIVERSITY OFFLORENCE

Elena Acuti, Scilla Bellucci, Laura Beritelli, Alberto Binazzi, Matteo Borri,Giovanni Casini, Roberto Ciuni, Chiara Erbosi, Marco Fenici, Riccardo Furi,

Matteo Leoni, Stefano Liccioli, Umberto Maionchi, Daniele Romano

HUMANA.MENTE- QUARTERLY JOURNAL OF PHILOSOPHY

Editorial

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T ABLE OFCONTENTS

I NTRODUCTION

Physics and Metaphysics. Introduction p. III

R EPORTS

The Third Interdisciplinary Ontology ConferenceTokyo, Japan, 27-28 February, 2010reviewed by Michele Pasin p. XIX Winter School: "Open Problems in Philosophy of Sciences"

Cesena, Italy, 15-17 April, 2010reviewed by Pierluigi Graziani p. XXV

P APERS

Mauro Dorato Physics and Metaphysics: Interaction or Autonomy? p. 1

Gabriele Veneziano

String Theory: Physics or Metaphysics? p. 13 John NortonTime Really Passes p. 23

Sam Baron, Peter Evans, Kristie Miller From Timeless Physical Theories to Timelessness p. 35

Vincent Lam

Metaphysics of Causation and Physics of General Relativity p. 61Claudio Garola, Sandro Sozzo Realistic Aspects in the Standard Interpretation of QuantumMechanics p. 81

Giovanni Macchia Expansion of the Universe and Spacetime Ontology p. 103

Adriano Angelucci, Vincenzo FanoOntology and Mathematics in Classical Field Theories and Quantum Mechanics p. 139

Tracy Lupher Not Quite Particles, Not Quite Fields p. 155


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Friedel Weinert Relativistic Thermodynamics and the Passage of Time p. 175

BOOK R EVIEWS

Bastiaan C. Van Fraassen - Scientific Representation: Paradoxes of Perspectivereviewed by Bradley Monton p. 193

Yuri Balashov - Persistence and Spacetimereviewed by Lorenzo Del Savio p. 201

Steven French and Decio Krause - Identity in Physics: a Historical,Philosophical and Formal Analysisreviewed by Giovanni Casini p. 209

Tim Maudlin - The Metaphysics Within Physicsreviewed by Emanuele Coppola p. 213

Carlo Rovelli - Anaximanderreviewed by Umberto Maionchi p. 219

COMMENTARIES

A Structural Interpretation of Pure Wave Mechanicsedited by Jeffrey Barrett p. 225

Metaphysical Language, Ordinary Language and Peter van Inwagen'sMaterial Beingsedited by Daniel Nolan p. 237

Michael Lockwood - The Labyrinth of Time: Introducing the Universecommented by Giuliano Torrengo p. 247

Robert Geroch - General Relativity from A to Bcommented by James Weatherall p. 259

I NTERVIEWS

Adolf Grunbaum p. 267


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IntroductionPhysics and Metaphysics

Claudio Calosi *

[email protected]

1. PHYSICS AND METAPHYSICS. A N OVERVIEW

It is notoriously difficult to define Metaphysics1, its content, its method, itslanguage, its scope. Thus I will not even try an attempt here. I will rest content to point out some widely held characterizations. A long and highly influentialtradition maintains that Metaphysics is the study of being qua being. It isconcerned with what there is, what kind of things are the things that there are, what properties do they have, how they are related. In this sense Metaphysicsdeals with the more general features of reality, the most fundamental categoriesof being. Call this traditionGeneral Metaphysics .

It is well known that empiricism of any sort 2 has always been very skepticalof the very possibility of such an enterprise, at least one it considered anenterprise that should be carried out a- priori. Kants transcendentalismsomehow endorsed this skepticism about General Metaphysics yet it did not dispense with Metaphysics in general. Metaphysics, according to this Kantianstandpoint, is nothing but the clarification of the most general structures at work in our knowledge of the world. Call thisTranscendental Metaphysics .

Strawson (1959) famously introduced a distinction betweenDescriptive andrevisionary, orPrescriptive Metaphysics . Descriptive Metaphysics aims todescribe the most general features of our conceptual scheme. PrescriptiveMetaphysics, on the other hand, attempts to revise our ordinary way of thinking and our ordinary conceptual scheme in order to provide an intellectually andmorally preferred picture of the world. It could be argued, though this might turn out to be a controversial claim, that in some sense Descriptive

* Department of Philosophy University of Florence1 See for example discussion in Loux 1998 and van Inwagen 2007. There is whole industry now

in the analytical community that deals specifically with such questions. It is called Meta-metaphysics.2 Both classical Empiricism of Locke and Hume and logical Empiricism of Carnap, Reichenbach,

Ayer.


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Metaphysics is the continuation, or a contemporary variant, of TranscendentalMetaphysics and that Revisionary Metaphysics is a continuation, or a contemporary variant of General Metaphysics. It remains the fact that bothtraditions are alive in contemporary analytical philosophy.3

Physics on the other hand might at first seems easier to define, at least sincethe publication of GalileosDiscourses and Mathematical Demonstrations relating Two New Sciences in 1638, that can as well serve as the birthmark of modern mathematical physics. A very rough characterization of it will probably mention the study of matter and motions of matter through spacetime. In a broader sense Physics deals with the general analysis of nature, the world andtheir components.4

It is immediately clear, even from these very sketchy presentations how wideand deep is the area of overlap between these two disciplines. For clearly,matter, space, time and so on do seem, at least at first sight, good candidatesfor the alleged general categories of being or general categories of humanunderstanding. Another, I believe straightforward, empirical argument in favorof the existence of such a deep an wide overlap, comes from a look at contemporary introductions to Metaphysics, even if it is a brief and quick look.5 They almost invariably contain materials on space, time, causation,constitution of material objects, identity, determinism and free will and so on.But these are the very notions Physics is supposed to be about.6

If my argument is sound then this overlap immediately raises deep issuesabout the relationship between Physics and Metaphysics. There is almost aninfinite variant of positions one might hold. I cannot do justice to them here.7 So I will rest content at rehearsing some of those. It seems to me that the twoextreme positions one might maintain can be labeledMetaphysical

3 I invite to read this claim not as a militant claim but rather as a pragmatical one. It just serves to purpose of delimiting boundaries that, even if artificial, are sometimes useful if not implicitly sustained.

4 I use these terms in a very loose way. Thus I do not want to suggest that there is a difference between the world and nature or that components should be understood as parts or participants forexample. Mine is a claim of humility. An introduction is not the place to settle discussions that haveshaped the very course of Western Thought.

5 See for example again Loux 1998 and references therein.6 Probably free will will not be explicitly mentioned in any physics textbook. However in

contemporary metaphysics the issue of free will is deeply connected to the issue of determinism, andthis is surely a topic physics deals with.

7 I refer the reader to the excellent Dorato (this volume).


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Foundationalism (MF) andPhysical Eliminativism (PE).8 According to MF,Metaphysics is the study of the most general feature of reality independently of any particular science. Metaphysics provides the general framework in whichany empirical considerations, physics included, become meaningful.9 ThusMetaphysics is the foundation of every empirical science, Physics included. Idoubt that anyone would endorse such an extreme version of foundationalismnowadays, although it could be argued that formal ontology is precisely a contemporary variant of such attitude.10

On the other hand PE maintains that there are no genuine metaphysical problems. There are only the empirical questions asked by Physics. Supposefor sake of argument that Physics could solve all of its problems. Then there will be no problems left to solve.

Between these two extremes there is a wide range of options. One might uphold a sort of Naturalistic Attitude (NA). Proponents of NA do not deny that there are genuine metaphysical questions about, for example the nature of existence, but they do deny that those questions can be solved or evenformulated or even arise11 independently of any physical considerations.12 According to such an attitude whether God exist is not a genuine problem afterall13. But it is a genuine metaphysical problem whether the electromagneticfield exists and whether it supervenes or not on charged particles. But naturally this question does somehow depend on physical considerations, mainly

8 Here and in what follows I will not make any attempt to decide whether any particular philosopher would endorse any particular thesis.

9 I am perfectly aware that strictly speaking this claim does not follow from the previous one. But

I am not attempting to give a rigorous definition of Metaphysical Foundationalism here.10 One of the authors in the volume, Vincenzo Fano, has suggested me a different taxonomy of the possible relationships between Physics and Metaphysics. Here I briefly sum up his argument. i)Genuine metaphysical problems are just foundational problems of physics, or foundational problemsof natural science in general. It would be interesting to assess whether this is my NA. ii) There are genuine metaphysical problems but they have to be formulated keeping in mind the technicalresources used by physical sciences. Again, it is interesting whether this is an instance of my NA again.iii) Metaphysical problems are independent from physics in their formulation but they might be solved by physics. iv) Physics has no relevance whatsoever for metaphysics. This seems to be a stronger variant of my IT. v) There are no metaphysical problems. It is probably a strong variant of my PE.Thanks to Vincenzo Fano for helpful comments on a previous draft of this work.

11 Depending probably on the strength of such naturalistic attitude.12 Or broadly speaking independently of any considerations drawn from natural sciences in

general.13 Though this might be a strong controversial claim even for those who have naturalistic

inclinations. Some of them will probably argue that Physics do have something to say about that question. And some would go probably as far as saying that Physics does settle that question.


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classical electromagnetism and quantum electrodynamics. Another possibility would be to hold anIndependence Thesis (IT). IT

would probably claim that Physics and Metaphysics are two independent disciplines with their own language, their own methodological and theoreticalcomponents. Sometimes they do overlap. And when they do they are both best understood as incomplete descriptions of the same portion of reality.

Someone willing to accept the distinction in Strawson 1959 that I havementioned above might want to argue that Physics and Metaphysics are bothindependent and distinct and that the only viable Revisionary Metaphysics isPhysics and that the only viable Metaphysics is Descriptive Metaphysics. I leaveit to the reader to explore whether this option is just a variant of NA, IT or a combination of both.

It is clear however, or, at least it should be clear, that whatever thesis onemight hold about the relationship between Physics and Metaphysics this callsfor substantive argument.14

I am personally inclined to think that Metaphysics without Physics is blindand physics without metaphysics is crippled. This claim should be understoodtentatively along the following lines. Our metaphysical theories should beinformed by our best, experimentally successful physical theories. I would probably go as far as claiming that a contradiction with a well confirmed physical theory should be a reason good enough to seriously consider the possibility that a certain metaphysical theory is simply false But it is also thecase, I believe, that our best physical theories are not metaphysically transparent. To read off a particular metaphysics from a physical theory sometimes, if not always, requires substantive work that is not and cannot bedone by the physical theory itself. I would probably go as far as claiming that there are genuine metaphysical questions for which physics by itself does not have the answer. This conviction was what first motivated me to embark in the present work. It follows from this conviction that an interaction betweenPhysics15 and Metaphysics is necessary and should be welcome. In what followsI will provide what I take to be an interesting case of fruitful interaction between those two.

14 Again, see Dorato (this volume) and references therein.15 And naturally philosophy of physics.


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2. PHYSICS AND METAPHYSICS. A N EXAMPLE

My arguments in section 1 notwithstanding, it is a widely recognized fact that Metaphysics and Physics have been rather self isolated enterprises, even in theanalytical community. On one hand, metaphysical issues about identity,location, persistence through time, material composition, causation and so on have rarely been discussed within the framework of physical theories. On theother hand, Physics and philosophers of physics have somehow endorsed a form of skepticism along the lines I have sketched in section 1 about the possibility for Metaphysics to provide a consistent and valuable view of how the world is. In recent years however there has been a tendency to bridge the gap between the two. Considerations drawn from physical theories have played a major role in metaphysical disputes like the ontology of time, nature of persistence, theory of identity and even mereology, to name just a few. Thissection explores one particular case in which considerations drawn fromPhysics and philosophy of Physics have been fruitfully used to deepen, clarify,and arguably, solve classical metaphysical issues.16 The case I have in mind isSpecial Theory of Relativity 17, and its consequences for Metaphysics of Timeand Metaphysics of Persistence. I am choosing this example for different reasons. First of all providing a general and compelling argument about therelationship between Physics and Metaphysics is far beyond my possibilities. Ileave this problem to better hands than mine.18 Second this example is what Iam mostly concerned with. And finally it is briefly mentioned in various worksin the present volume19 yet not directly addressed by any of those. So hopefully this will not affect any reading of the papers, which are the main strength andshould be the main focus of the present issue. These seem to me good enoughreasons.

16 Again, I leave it to the reader to judge if my own take of the problems is an instance of NA ornot.

17 STR from now on.18 And again here, see Dorato (this volume).19 See in particular Norton, Barons, Evans and Miller, Weinert, Torrengo and Dorato (this

volume).


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2.1 SPECIAL THEORY OF RELATIVITY AND METAPHYSICS OF TIME20

There are famously three different Metaphysical theories about Time21, namely Presentism, Possibilism and Eternalism. They can be roughly defined along thefollowing lines:

(1) Presentism i) Only the Present exist, the Past and the Future donot, and22 ii) Only Present Objects exist.23

(2) Possibilism i) Only the Present and the Past exist, the Futuredoes not, and ii) Only Present and Past Objects exist.24

(3) Eternalism i) Past, Present, Future, they all exist, and ii) Past,Present and Future Objects they all exist.

It is widely held that STR provides one of the most compelling argumentsagainst Presentism. If this is indeed the case25 then this is a clear example in which considerations drawn from a specific physical theory are used to solvetraditional metaphysical problems. It should be noted however that physicalconsiderations play a much subtler role than it is usually recognized. For they

do not enter only in the solution of the metaphysical problem. They enter, or better, I think they should enter, even in the formulation of it. Claims (1)-(3)are cast in temporal language. It is however controversial whether there is timeat all in a relativistic world.26 Startling as it might be this claim has authoritativedefenders.27 Even if someone is not willing to go as far as denying the existenceof time in a relativist world one might still worry about the fact that STR is best

20 This section is not supposed to be an exhaustive treatment of such issues. It should give the

reader a flavor, so to say, of how a fruitful interaction between Physics and Metaphysics might work.For a careful analysis see Calosi (unpublished).21 I am taking for granted that these debates are genuine metaphysical debates and not just

semantic debates in disguise. Those who are inclined to endorse such a semantical skepticism shouldread my claims counterfactually.

22 The justification for this conjunction is based upon some implicit technical assumptions about reducibility of objects to spacetime regions. It should be noted that the presentism eternalism debateis not to be confused with another classical debate in philosophy of time, namely the debate between A-theory of time and B-theory of time.

23 I am personally inclined to read this claim within the framework of a formal theory of location.Such a theory is a formal theory in the logic sense. It is a set of definitions, axioms and theorems in thelanguage of the first order calculus. See again Calosi (unpublished).

24 In what follows I focus on Presentism. Most of the arguments will apply to Possibilism too sothere is no need to distinguish here.

25 As I maintain it is.26 See the excellent Barons, Evans and Miller (this volume).27 Most notably Barbour, Pooley and Stein.


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understood as a spacetime theory that attributes a particular geometricstructure on the world, namely that of Minkowski spacetime.28 And Minkowskispacetime is not just space and time.29 Thus one might endorse some sort of Supervenience thesis according to which temporal facts supervene onspatiotemporal facts. If so, my formulation in (1)-(3) is, if not mistaken, at least misleading. Fortunately enough it is not difficult to find a formulation of such a debate that is more relativistic friendly. It can be reconstructed along thefollowing lines:

(4) Relativistic Presentism: i) There exists only one particularsubregion of Minkowski spacetime that is called the Present, andii) there exist only those objects that are located at that subregionof Minkowski spacetime that is mentioned in i).30

(5) Relativistic Eternalism: i) There is no ontological distinction between different subregions of Minkowski Spacetime, and ii)objects do not lose or acquire any particular ontological status just by be merely located at them.

There are at least two main relativistic arguments against Presentism, both asdefined as in (1) or (4). I label themThe Relativity of Simultaneity Argument and the No Spatially Extended Present Argument . Here is a brief reconstruction of both, starting with theRelativity of Simultaneity Argument :

(6) STR is true.(7) If STR is true there is no absolute, i.e., frame independent,

relation of simultaneity.31

(8)

If Presentism is true than there is absolute simultaneity.(9) Hence Presentism is false (by (6), (7), (8)).

The No Spatially Extended Present Argument instead runs roughly as follows:

28 That is a n-dimensional metric affine space with signature (1, 1-n) where n4.29 The reader should grant that for sake of argument, namely the fact that time is not just the

timelike submanifold of Minkowski spacetime and space is not just the spacelike submanifoldorthogonal to it. Again, to see how an argument towards this conclusion can be constructed, seeBarons, Evans and Miller (this volume).

30 Even this formulation is not satisfactory in many ways. I cannot enter into these subtleties here.31 This follows from the following facts about Minkowski Spacetime. Simultaneity is represented

geometrically by Minkowskian orthogonality, i.e., two events p and q are simultaneous relative to a timelike line L iff = 0 where u is an arbitrary timelike vector that spans L. Vectors are writtenin bold characters. But different timelike lines will single out different spacelilke submanifoldsorthogonal to them and so different events could count as simultaneous relative to different lines.


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(10) If STR is true there is no spatially extended present.32 (11) If Presentism is true then there is a spatially extended present.(12) Hence, Presentism is false (by (6), (10), (11)).

A careful and detailed analysis of such arguments is beyond the scope of thisintroduction. But it is important to note something about them. They seem33 toassume implicitly the following premise, where event should be taken to be,loosely speaking, as the content of a spacetime point.

(13) The Present of an event e1 is the region of spacetime that contains all and only those events that are absolutely simultaneous with e1.

Then, given (13) it is possible to derive the geometry of such a region fromthe geometry of Minkowski spacetime and go on to argue as in (7)-(9) and(10)-(12). But (13) is not supported by STR itself. It is rather a metaphysicalclaim that could be resisted on metaphysical grounds. Thus anyone who is willing to question (13) should be able to resist both the arguments I have

presented. If I am right this is a very nice example of how much subtler anddeeper the interrelations between physical and metaphysical considerationsare. I should note here that I do believe that a new, more compelling and moresophisticated relativistic argument can be given against Presentism. Here I canonly give a brief sketch of it.34

(14) If Presentism is true, on pain of contradiction, every event should belong to just one privileged subregion of Minkowski spacetimethat is suitable to represent geometrically the Present.

(15) If so the relation of belonging to such a subregion is anequivalence relation (by (14)).

(16) There are no equivalence relations that are definable in terms of the geometric structure of Minkowski spacetime35 beside theidentity relation and the universal relation (by the geometricstructure of Minkowski spacetime).

32 This claim is allegedly based upon the causal structure of Minkowski Spacetime.33 Though I know that this might be, again, a controversial claim.34 For a detailed presentation see Calosi (unpublished).35 This is due to facts about signature and facts about causal isomorphisms of Minkowski

spacetime, i.e., maps of the form: A A where A is the underlying affine space that preserves thecausal structure. Formally if pKq stands for p is causally connectible with q then invariance undercausal isomorphism can be written as pKq (p)K (q).


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(17) If the relation in question is taken to be the identity relation thenPresentism implies that there exists only one spacetime point.(by (1) or (4) and (16)).

(18) It does not exist only one spacetime point.(19) Thus the relation in question is the Universal Relation (by (16),

(17) and (18)).(20) If the relation in question is the Universal relation it follows that

every spacetime point is in the present of every spacetime point. And so every spacetime point is real. Thus Eternalism follows.

It is not possible to assess whether this argument is successful here.

2.2 SPECIAL THEORY OF RELATIVITY AND METAPHYSICS OF PERSISTENCE

While observations drawn from STR have played a considerable role inMetaphysics of Time at least since the seminal Gdel (1949) and Putnam(1967), they have been almost absent from another metaphysical debate,namely the one concerning Metaphysics of Persistence, until fairly recently.36 Things persist through time. This much seems uncontroversial. Thecontroversy is how they do so. Famously there are two main Metaphysics of Persistence37, namely three and four-dimensionalism. Let me start by giving a rough definition of a three and a four-dimensional object.

(21) x is a 3D object df x is a persisting object that persist throughtime by being wholly present at each time of its existence, thusnot having any temporal parts.

(22) X is a 4D object df x is a persisting object that persists throughtime by having a different temporal part at each time of itsexistence.

Then three and four-dimensionalism can be stated as

(23) 3D every material object is a 3D object.(24) 4D every material object is a 4D object.

36 Yuri Balashov is the one who first suggested a detailed relativistic argument in favor of a particular metaphysics of persistence, namely four-dimensionalism. This argument is improved in hisBalashov (forthcoming). See the beautiful Del Savios review in this volume.

37 I am leaving the possibility of stage theory or exdurantism aside. From a strict ontological point of view this theory can be seen as a variant of four-dimensionalism. From the metaphysical point of view there is however, I believe, room for disagreement.


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It is clear that this formulation of the debate over the Metaphysics of Persistence is centered about the existence of temporal parts. Call this way of formulating the problem Mereological Persistence. Even in this case STR has played a considerable role even in the formulation of the problem. As it turnsout the task of giving a precise formulation of the central notions in the debateover Mereological Persistence, namely the notion of temporal part and thenotion of being wholly present, is very far from trivial. This difficulty has raiseda considerable amount of skepticism over those notions and thus over theentire debate. STR itself proves a substantive argument in favor of a reformulation of the debate. The central notions are in fact again cast in purely temporal terms and thus they fall short of the Supervenience argument of the previous section. But STR itself, and more generally, spatiotemporal theories have proved to be fruitful instruments to recast the debate in different terms. An alternative formulation of the debate centers around the notion of location,in particular the notion of exact location.38 The driving intuition behind thenotion of the exact location is that an object and its exact location share all therelevant geometrical properties. Thus the exact location of my hand will be a hand shaped region, the exact location of a square with the side of one inch will be a square spacetime region whose sides do measure one inch and so on. Let me introduce some terminology. I will write39

(25) ExL (x,R) for x is exactly located at spacetime region R df x andR do have the same geometrical properties.

(26) OvF (x,R) for x overfills R df ExL (x, R 1) (R


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is multiply exactly located at different non overlapping temporally unextended43 spacetime regions while a four-object is an object that is singly exactly located at a temporally extended spacetime regions. These claimsactually capture the powerful intuition according to which three and four-dimensional objects do have different geometrical properties. The last piece of notation is grounded in the geometric structure of Minkowski spacetime. I will write

(28) Achr (R) for R is an achronal region of Minkowski spacetime

df ( p) ( q) (p R q R) pq is spacelike.44

Then a persisting object x is defined via

(29) Pers (x) for x is a persisting object df Achr (Path (x))

and three and four-dimensional objects can be given the following precisedefinitions:

(30) x is a 3D object df Pers (x) ( R 1) ( R 2) (R 1 R 2 ExL (x,R 1)

ExL (x,R 2) Achr (R 1) Achr (R 2) Achrn (R 1 R 2)).45

(31) x is a 4D object df Pers (x) ExL(x, Path (x)) (ExL (x,R) R

Path (x)).

Informally definitions (31) and (32) say that a 3D object is an object that ismultiply exactly located at different achronal subregions, while a 4D object isan object that is exactly located at a single non achronal subregion, namely its path.

Then three-dimensionalism and four-dimensionalism can be formulatedagain via (23) and (24). Call the present formulation of the debate LocationalPersistence.46 This long formulation of Locational Persistence is again a fineexample of a case in which physical considerations have proved fruitful inreformulating a typical metaphysical problem.

Within the background of locational persistence different relativisticarguments against three-dimensionalism have been put forward. In what

43 The relativistic counterpart of this notion is achronality. See later on.44 Where pq is spacelike iff < 0.45 Note that Pers (x) is redundant here. This definition of a 3D object can indeed be improved

upon, but I cannot refine it here.46 I cannot enter here into the subtleties about the relationships between Mereological

Persistence and Locational Perisistence.


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follows I briefly rehearse two of them, theExplanatory Argument due to YuriBalashov 47 and the Location Argument due to Cody Gilmore48, beforeaddressing one of my own relativistic arguments the Relativistic Argument from Change.

The Explanatory Argument is a typical inference to the best explanationarguments. It follows from STR and thesis about Locational persistence that the same object will have different 3D shapes relative to different frames.Three-dimensionalism will not have any explanation of why different and loose3D shapes form a remarkable unity and come together to form a smooth four-dimensional volume. Four-dimensionalism on the other hand has a ready andsimple explanation. This is due to the fact that different 3D shapes are just cross section of a four-dimensional object.49

The Location Argument maintains that three-dimensionalism cannot ans wer the so called Location question. Heres the location question. Let x be a material object. What subregions of Path (x) does x exactly occupy? Four-dimensionalism has a ready answer. Since x is a 4D object it will exactly occupy the only proper subregion of Path (x), namely Path (x) itself. But if x is a 3Dobject it exactly occupies just achronal slices of Path (x). But which ones?Gilmore suggests different answers to this problem and discard them all using arguments based on relativistic consideration. And this again suggests that four-dimensionalism is somehow favored by STR.

To conclude the section I will briefly sketch one of my own relativisticarguments. I can only give a rough presentation of it. I have labeled it elsewhere theRelativistic Argument from Change . Think for a moment to theclassical case. Suppose x is a 3D object that changes from having the property F at time t 1 to having the property F at time t 2. On pain of contradiction x cannot have two incompatible properties. Traditional three-dimensionalist solution to this problem maintains that properties should be somehow relativized to times. Let me write F-at-t 1 (x) for x has the property F at t 1. ThenF-at-t 1 and F-at-t 2 are not incompatible properties and the problem fromchange vanishes. Given Locational Persistence this strategy will involve that 3D

47 See his Balashov (forthcoming) reviewed in this volume. This work contains at least anotherinfluential relativistic argument in favor of four-dimensionalism, namely the so called coexistenceargument.

48 See his Gilmore 2007 for a detailed presentation.49 This argument has been challenged many times. The interested reader should read Balashovs

own discussion in Balashov (forthcoming).


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objects have properties relativized to spacetime regions they occupy. I will write

(32) F-at-R 1 (x) for x has property F at spacetime region R 1.

Now suppose x is a 3D object that is exactly located at two different overlapping achronal subregions of Minkowski spacetime R 1 and R 2. The fact that x can be exactly multi-located at R 1 and R 2 follows directly from thedefinition of a 3D object. The fact that those regions can overlap comes fromthe fact that the best answer to the Location Question presented above a three-dimensionalist has is that x exactly occupies every achronal slice of Path (x).50 Then possibility of change implies that x can have incompatible properties at R 1 and R 2. Consider now the following property, being uniformly F, defined via

(33) UnF-at-R (x) ( R 1) (OvF(x,R 1) F-at-R 1(x)).

Claim (33) just says that if x is Uniformly F at one of its exact locations it is F at every subregion of that exact location. It follows from definition of Overfill that every region x does overfill is a subregion of its exact location. Now everything is in place for the new relativistic argument. I am presenting it in a shortened version.

(34) UnF-at-R 1 (x) (assumption).(35) Un F-at-R 2 (x) (from possibility of change).(36) ( R) (R


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structure of Minkowski spacetime. In a classical spacetime a 3D object will infact never be exactly multiply located at different but overlapping regions.There are ways to resist the argument but I contend that they all fail. It is not my intention to defend conclusively this argument of mine here. I just wantedto give it as an example of interaction between physical and metaphysicalconsiderations.

3. PHYSICS AND METAPHYSICS. STRUCTURE

The present volume of Humana.Mente embodies perfectly the spirit of the first two sections. It tries to bridge the gap between Physics and Metaphysics, bothin an historical52 and in a more theoretical perspective. It offers examples of theinteraction between Physics and Metaphysics at their very best. The volumecontains discussion of various physical theories ranging from Relativity Theory (Norton, Barons, Evans and Miller, Lam, Macchia), to Quantum Mechanics(Garola and Sozzo, Angelucci and Fano), from Thermodynamics (Weinert), toQuantum Field Theory (Lupher), from Electromagnetism (Angelucci andFano) to Quantum Gravity (Barons, Evans, Miller) to String Theory (Veneziano). Considerations drawn from these physical theories are used toclarify and solve traditional metaphysical issues. Among those who areexplicitly addresses in the volume we find the question of realism (Garola andSozzo), metaphysics of time (Norton, Barons, Evans and Miller, Weinert),causation (Lam), questions about cosmology (Macchia) and fundamentalontological questions regarding fields, particles and the spacetime structure(Lupher and Macchia respectively). Commentaries provide new takes onclassical texts on Physics and Metaphysics. They provide new challenging arguments on classical questions such as the relations between physicaltheories and phenomenology of experience (Barrett), the relations betweencomposition, strict metaphysical language and loose common sense language(Nolan), the relations between physics, mathematics and experience(Weatherall) and paradoxes of time travel (Torrengo). The volume alsocontains review of recent works that I am confident will provide a fundamentalcontribution to the discussion in the field for many years to come. These worksinclude authors such as Maudlin, Rovelli, French and Balashov.

52 See mainly Angelucci and Fano (this volume).


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Introduction Physics and Metaphysics XVII

Finally this issue has the privilege to have an interview with A. Grnbaum,that many will probably regard as one of the highest vertex when it comes to the philosophical enquiry on Physics and Metaphysics. And with this I leave thereader to the volume.

Acknowledgments I would like to thank all of the people that made this volume possible, all of the authors that

have written, all of those who have submitted papers, all of the referees that have done animpressive work. I would also like to thank people that have supported me and this work inmany different ways, among them Paolo Parrini, Achille Varzi, Paolo Valore and Cody Gilmore. Naturally this work could not have possibly seen the light without Duccio andSilvano. To them not only a thanks but a glass of wine.

REFERENCES

Aristotle (1991). The Metaphysics . (tr. by J. H. McMahon). Amherst:Prometeus Book.

Balashov, Y. (2010).Persistence and Spacetime . Oxford: Oxford University Press.

Calosi, C. (unpublished).Time and Objects in Minkowski Spacetime . Ph.D.Thesis. Florence: University of Florence.

Gilmore, C. (2007). Where in the Relativistic World are We?.Philosophical Perspectives, 20 (1), 199-236.

Lange. M. (2002). An Introduction to the Philosophy of Physics . Malden:Blackwell Publishing.

Loux, M. (1998). Metaphysics: A Contemporary Introduction . New York:Routledge.

Strawson, P. F. (1959).Individuals . London: Methuen and Company.

Van Inwagen, P. (2007). Metaphysics.Stanford Encyclopedia of Philosophy .

Varzi, A. (2009). Mereology. InStanford Encyclopedia of Philosophy .


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Report Third Interdisciplinary Conference

InterOntology10* Keio University, Tokyo, 27-28 February 2010

Michele Pasin** [email protected]

The third Interdisciplinary Ontology Conference was held in Tokyo, Japan,from February 27 to February 28 2010. Organized by the Japanese Center forOntological Research (JCOR) and cosponsored by the Japanese Government sMinistry of Education and Science (MEXT), the stated goal of this forum is tosupport the exchange of ideas and state-of-the-art technologies for those working in the ontology domain from around the world. The event has a quiteunique flavor, for it gathers researchers from disciplines as disparate ascomputer science, logic and philosophy, as well as a variety of applicationdomains. The common thread is the discipline of ontology, which hasundoubtedly gone a long way since its early days in ancient Greece.

We all know that ontology began as a branch of philosophy, studying thetypes of entities in reality and the relations between them. In the seventies, theearly researchers in artificial intelligence borrowed the word from philosophy and applied it to their discipline. Consequently, if ontology used to be intendedas a systematic account of Existence, within this new context, what exists has become that which can be represented using a computer. Disciplines such asontology engineering were soon to be born, which investigated (among variousother more technical aspects) how to best employ the rich body of theory from philosophical ontology to the purpose of making conceptual distinctions in a systematic and coherent manner. Nowadays ontology has become anestablished branch of computer science, which offers solutions to problem inareas as disparate as data integration, information retrieval, natural language processing, industrial planning and many others.

* I would like to thank the Japan Society for the Promotion of Science (www.jsps.go.jp) for giving me the means to attend this conference.

** King s College London


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As already mentioned, it is not uncommon for this conference s attendeesto be almost unable to follow a talk, for it uses the word ontology in a way never heard before. This is, on the contrary, one of the most interesting aspectsof the strongly interdisciplinary meeting. In the review that follows we hope to give to the reader a small taste of this feeling, and a better appreciation of themany senses we can talk about ontology in 2010.

Achille Varzi s paper titledOn the Boundary Between Material and Formal Ontology sets the scene for the whole conference. Material ontology, the onemade popular by Quine, is concerned with the question of what there is, whileformal ontology, often related to the work of Brentano and Husserl, focuses not on what there is but on the formal structure of what there is. So, for example,the former may include debates on whether abstract particulars exist or not, orarguments in favor of the existence of holes. Instead under the heading of thelatter we might find issues such as whether an entity is self identical or not, orattempts to prove that no entity can consist of a single proper part. In general,the second type of ontology is concerned with the general features of what exists, independently of what that is. Thus, formal relations such as identity, parthood or dependence should be rightly investigated by formal ontology, andkept separated by the more specific problems of material ontology. This is thetraditional view on the subject but, Varzi challenges us, is the boundary soclear? With a well-developed argument, the author argues that one cannot pursue one sort of theory without also engaging in the other. In other words,the tasks of material ontology presuppose the backing of some formal-ontological theory, and that not always formal ontology can be in thematerial sense of the word, ontologically neutral.

Antony Galton with the paperHow is a Collection Related to its Members? gives us a first tasting of the depths of formal ontology by discussing the oftenneglected relationship of membership between an object and a collection too which it belongs. If a choir may be regarded as a collection of singers not just an arbitrary collection of singers, but a group of singer that have formed anagreement to come together for the purpose of performing certain types of music how shall we characterize the relationship between the choir and thesingers? The obvious first answer can be that the singers are the choir; howevera more rigorous ontological analysis would impose us to define what we mean by are in the previous statement. If are stands for an identity relation, then we would immediately have to face the problem of a singular thing being identical to a plural one. Galton takes us through two possible solutions to this


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problem, which are considering a collection equal to the mathematical set of itsmembers, or considering it equal to the mereological sum of its members, but in both cases he concludes that we have not gained any new ground. We must then admit that the collection issui generis , and cannot be identified withanything that we can specify independently. Consequently, a relation ot herthan identity seems to be needed here. According to Galton, we can approachthis issue by looking at an analogous ontological problem about which therelevant literature is much more abundant. In fact, the relationship between a collection and its members is analogous to the relationship between a materialobject and the matter it is made of, and the relation between an assembly and itscomponents. Therefore a thorough consideration of the principal philosophical positions related to the latter problems (such as eliminativism,constitution and four-dimensionalism) will help us elucidate matters withrespect to our initial issue. Furthermore, Galton points out a new possiblealternative, which is based on distinguishing synchronic and diachronic formsof identity. This approach, he says, has often been discarded as impracticableor bizarre, but it is worthwhile exploring especially in relation to the formalcharacterization of collections.

The article of John Bateman,Ontological Modularity: Unity in Diversity , gives us a brief tour of the type of problems computational ontologists have totackle. Bateman reports on the work of the Collaborative Research Center forSpatial Cognition, an interdisciplinary team sponsored by Bremen andFreiburg universities that investigates the acquisition, organization,utilization and revision of knowledge about spatial environments, be it real orabstract, human or machine. The range of computational systems that benefit from this type of research is quite vast: for example, we can think of softwaresfor human-robot interaction, ambient assisted living or architecture and building specifications. One of the great issues in this area, says Bateman,comes from the need to provide explicit models that do justice to a ratherdiverse set of requirements. Such requirements, in general, can be groupedunder three major headings. First, we have formal ontology, which has long been attempting to create a coherent formal characterization of the spatial properties of objects. Second, there is linguistic, which accounts for all theusage of spatial expressions in natural language. Third, we have qualitativespatial representation and reasoning, a research area in artificial intelligencethat (broadly speaking) poses the accent on the creation of decidable spatialmodels of reality, that is, models that can be used productively by computers. In


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his article, Bateman shows that too often all of these three approaches have been working in isolation, and that if confronted with each other they tend tochoose reductionist solution, so that one might arrange the three approaches hierarchically and make one set of distinctions more basic than other. Incontrast with this reductionist view Bateman advocates a radicalmultiperspectivalism , a view that does not rule out the possible incompatiblenature of different representations of space, but attempts to find the synergiesamong them. This can be achieved only if we use formal languages committedto notions of strong structuring , modularity and heterogeneity . In particular, he discusses the use of the Common Algebraic SpecificationLanguage (CASL), which embeds the principles above and therefore supportsthe creation of non-reductionist spatial ontologies.

Werner Ceusters and Barry SmithMalaria Diagnosis and the Plasmodium Life Cycle: The BFO Perspective is a good example of applied ontology in the biomedical domain. In their paper, the authors address the problem of producing a formal representation of the concepts of diagnosis, disease,symptom, disorder, pathological process and other biomedical notions. In particular, they look at the specific case of diagnosing malaria: this disease can be suspected on the basis of both symptoms reported by the patient and physical findings detected at examination; however, for a definitive diagnosis to be made, laboratory tests must demonstrate the presence within the patient of malaria parasites. To make the situation more difficult, some people areinfected but not made ill by the parasites, thus requiring a furtherdifferentiation between the concept of malarial illness and that one of malarialinfection. Ceusters and Smith show how their Basic Formal Ontology (BFO)can be used to put logical order among these concepts, so to create a coherent formal model which can support software applications in performing a numberof knowledge-intensive tasks. Another example of biomedical ontology is given by Christopher Baker and colleagues, with a paper titledLipid Ontologies . Inthis case the ontology addresses the problem that lipid research lacks a consistent nomenclature for lipids and that different lipid research groups have developed customized classifications of lipids that are relevant only for a restricted category of lipids. The authors therefore present their contributionas a rigorous formal ontology aiming at covering the subject area in a systematic and explicit way, to the aim of facilitating the process of data integration between different users.


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A more computer science perspective on ontologies has been given by Robert Meersman in hisHybrid Ontologies in a Tri-Sortal Internet of Humans,Systems and Enterprises . According to the author computational ontologiesmust be framed within an epochal change that includes the most recent technological advances in our society, such as the pervasiveness of computing devices, the participatory character of the web (the so-called Web2.0) and thetotal transformation of traditional business processes by means of the internet. Within such a scenario ontologies will achieve their intended purpose of facilitating the integration of information only if they get closer to the worldand daily practices of human beings. In other words, they must become hybridontologies, where concepts on the one hand are circu mscribed linguistically and (mostly) declaratively by agreement within (human) communities, and onthe other hand identified formally (and unambiguously) for use in computer- based information systems.

While all the articles presented so far have been given by invited speakers, a large portion of the conference consisted of contributed papers and researchreports. We are going to name just a few of them, as they are indicative of the broad horizons the Interontology conference usually has.Existence and Vagueness by Elisa Paganini attacks Sider s claim that the word exist is non- vague, even if intended as equivalent to an unrestricted existential quantifier.Claudio Calosi s Three-Dimensionalism and Formal Theories of Location composes and argument in favor of a four dimensional spatiotemporalontology. In DNA Sequences from Below: A Nominalist Approach , Yu Linthrows the basis for a formalization of molecular biology that does not requirethe existence of abstract objects. InBuilding up a Large Ontology from Wikipedia Japan with Infobox and Category Tree Takahira Yamaguchi andTakeshi Morita discussed how they used computational methods toautomatically extract an ontology from the community-constructed Japanese Wikipedia website. Finally, Makoto Sakai and Hiromichi Fukui have presentedOntology Study for Analysis and Anatomy of English-language News Relating to Human Security , discussing their use of ontologies to support disambiguation in a system that integrates online news articles.


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Report A School on Open Problems in Philosophy of

Sciences Cesena, 15-17 April 2010

Pierluigi Graziani * [email protected]

Philosophy, in its most serious and profound dimension, is about theconstruction of a justified solution to a particular class of fundamental problems; the philosopher is he who can argue for his answers to the problems, who knows how to put them in their place historically, who can rationally justify them and make them available for discussion and modification.

However, there are two points of view which concerns the relationship between philosophy and sciences and which does not endorse this prospect 1.

The first view rises from the fear of some philosophers that interaction between philosophy and sciences could result in an expansion of the latter anda reduction of the former; such a fear favors philosophical efforts for theconstruction of rigid boundaries between sciences and philosophy.

The second view, although allows an opening of philosophy with respect tosciences and takes scientific issues as starting points for philosophicalreflections, is however incapable of understanding the depth of those scientificissues.

Therefore, the first view transforms philosophical analysis in a mere a prioriactivity that is a sort of scholasticism; the second one, on the contrary,considers sciences, but only in an extrinsic way.

In such a context, a research school which focuses on open problems in the philosophy of sciences should be an attempt to support a more serious and profound idea of philosophy, one which, first, addresses problems from a historical point of view, by proposing solutions which are aware of thedevelopment of the debates and argued in a style as cogent as possible and,

* Urbino University 1 For a wider reflection, see Boniolo, S. (2002),Quattro questioni per ridiscutere sulla filosofia .

CxC Calls for Comments Sito Web Italiano per la Filosofia.


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second, picks the problems from the sciences and analyzes them withcompetence, care, skill, by grasping their essence and putting them in a general perspective.

With these purposes, following (mutatis mutandis ) the experience of twoschools in Francavilla al Mare organized by the Italian Philosophical Society 2,the schoolOpen Problems in Philosophy of Sciences 3 (Cesena, 15-17 April2010) has promoted and stimulated a methodologically conscious and mature philosophical analysis, capable of dealing with precision and deep culturalawareness with the problems raised by sciences.

The school, opened by such a distinguished scholar of philosophy of sciences as Evandro Agazzi, has allowed and stimulated a dialogue betweennew generationsof scholars (students close to completing their Doctors

degree, or Philosophy Doctors who have not yet achieved a permanent academic position) and distinguished professors such as Giovanni Boniolo,Mario Piazza, Alfredo Paternoster and Vincenzo Fano.

The school has fueled a dialogue open to scholars in the field, teachers of every grade and the entire civil society. Rather than talking about philosophy of science, scholars have shown how this discipline can and should be done by reflecting on important issues such as the Philosophy of the Life Sciences(Cecilia Nardini; Fridolin Gross; Fabio Lelli; Elena Casetta); the Philosophy of Mathematics (Gabriele Pulcini; Gianluca Ustori; Andrea Sereni; ValerioGiardino); the Philosophy of Mind (Maria-Erica Cosentino; Barbara Giolito;Maria Grazia Rossi; Maria Francesca Palermo); the Philosophy of Physics(Giacomo Mancin; Claudio Mazzola; Giulia Giannini; Giuliano Torrengo).

The school, organized by Gino Tarozzi, Vincenzo Fano, Mario Alai andPierluigi Graziani was made possible by a synergy between the Interuniversity Centre for Research in Philosophy and Foundations of Physics, theDepartment of Philosophy of University of Urbino, the Italian Society of Logicand Philosophy of Sciences and the Municipality of Cesena, which has beenfavoring for many years, mainly thanks to Franco Pollini, the Interuniversity Center in organizing major international events in the philosophy of sciences.

2 See: Tatasciore, C., Graziani, P., & Grimaldi, G. (Eds.) (2007),Prospettive Filosofiche 2006: Il Realismo . Napoli: Istituto Italiano per gli Studi Filosofici; Tatasciore, C., Graziani, P., & Grimaldi,G. (Eds.) (2010). Prospettive Filosofiche 2009: Ontologia . Napoli: Istituto Italiano per gli StudiFilosofici.

3 See .


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Physics and Metaphysics: Interaction or Autonomy?Mauro Dorato *

[email protected]

ABSTRACT

In this paper I will argue in favor of the view that if physics is to become a coherent metaphysics of nature, it needs an interpretation, namely (i) a clearformulation of its ontological/metaphysical claims and (ii) and a preciseunderstanding of how such claims are related to the world of our experience, which is the most important reservoir of traditional, merely aprioristicmetaphysical speculations.Such speculations especially if conducted in fullautonomy from physics, or imposed upon it from the outside risk to turnanalytic metaphysics into a rigorous but fully sterile intellectual game.

1. A N ATTEMPT AT CLASSIFYING POSSIBLE ATTITUDES

In order to defend this claim, I will begin by quoting some interesting remarksof Robert DiSallesUnderstanding Spacetime , where we find an historically grounded discussion about possible ways of characterizing the relationship between physics and metaphysics (DiSalle 2006, pp. 57-60). Some of hisremarks will be very helpful not only as a starting point to survey possible waysto characterize such a relationship in contemporary philosophy of physics, but also to understand, to a certain extent, the historical development of thisrelationship, and some future directions that it might take.

A first position that DiSalle does not discuss and that is, however, tooimportant and widespread to be neglected claims that physics and metaphysicsare to be regarded as completely independent of each other, so that they cannot conflict even in principle. This position amounts to a reciprocal attitude that when it does not amount to disrespect could be labelledTolerance .Tolerance means that the subject matter of the disciplines is to be regarded by their practitioners as completely non-overlapping, so that neither of the two

* Department of Philosophy University of Rome 3


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disciplines can claim to offer a more reliable description of the fundamentalstructure of reality. This stance is widespread among a significant number of contemporary philosophers or metaphysicians, who pursue their work without paying any attention whatsoever to what happens in the field of science, or physics in particular. Perhaps more significantly, this attitude is also advocated by the vast majority of physicists, who unconscious disciples of early neopositivism are convinced that physics has nothing to do with metaphysics.Physics is, and ought to remain, immune from metaphysics: possibly, the only metaphysical hypothesis that is needed by physics is, as Dirac used to say at the beginning of his lectures, that there exists an external world.

A second option consists in the attempt to subordinate one discipline to theother. Subordination, in its turn, here might mean two different things, asargued by DiSalle (2006, p. 57). On the hypothesis that physics andmetaphysics both try to offer a description of reality and could give conflicting claims about it, one could either claim that either physics or metaphysics iscloser to the truth than the other either on single questions or in general ortry to derive the principles of one discipline from those of the other. Let usdistinguish between these two attitudes, by naming the formerDenial and thelatter Explanatory Imperialism . Denial and Explanatory Imperialism have beenexercised much more on the part of philosophers over physics, than in theopposite direction. This asymmetry might depend on the sociological fact that in the last two centuries science has acquired much more prestige with respect to traditional metaphysics. Consequently, while physicists often implicitly believe that they can afford to ignore what happens in the field of metaphysicssince they are tracking the truth, the converse does not hold. Metaphysiciansfeel that they have to justify they own approach to things even if many of their beloved concepts (space, time, matter, number, motion, etc.) have become thesubject matter of science.

The historical figures of Descartes and to a lesser extent that of Leibniz represent the first clear example of Denial , namely the attempt to claim that metaphysics is closer to truth than physics.1 The reader will recall that Galileo was accused by Descartes of lacking a systematic method in his approach tonatural philosophy, and of being too absorbed by scattered and isolatedempirical questions. On the other hand, Newtons physical hypotheses wereattacked by Leibniz on the basis of metaphysical and theological principles (the

1 See also DiSalle 2006, p. 57.


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Identity of the Indiscernibles, and the Principle of Sufficient Reason applied toGods choice). Notably, in contemporary metaphysics this attitude of Denialseems lost: even those who tamper with Special Relativity for purely metaphysical reasons2, do not deny the fact that the scientific theory they consider has some claim to (approximate) truth; in the example at hand, they simply supplement it with an unobservable reference frame which, as such,does not contradict the theory, but only its spirit.3

The third possibility,Explanatory Imperialism , also grants metaphysicssome sort of superiority over physics, and according to DiSalle is exemplified by the great mathematician Euler and by the early Kant. By granting the possibility that the principles of physics may be taken at face value, and neednot be rejected in the name of metaphysics, such a third view still assignsmetaphysics the task to understandwhy those physical principles hold (DiSalle2006). In other words metaphysics has the task to explain the basic principle of physics, by deriving them from deeper aprioristic, metaphysical truths. Alsothis third attitude, in contemporary metaphysics seems completely lost. BothDenial and Explanatory Imperialism seem two attempts at resisting a fundamental change in ways of acquiring knowledge about reality: fromaprioristic analysis to empirical inquiry supplemented by mathematical models.

Interestingly, the mature Kant realised that after NewtonsPhilosophiae Naturalis Principia Mathematica traditional metaphysics had no future.Transcendentalism or Foundationalism is the attempt to using philosophy orthe theory of knowledge to inquire into the very possibility of physics (andmetaphysics), namely to dig out those apriori structures of the transcendentalsubject that make physics (and mathematics) possible. In a nutshell, according to Kants Critique of Pure Reason, Newtonian physics is a fact, and his theory of knowledge explains why it holds necessarily and universally, against thedoubts raised by Humean scepticism with respect to the universal validity of physical laws. Contemporary Neokantians give up the idea that our aprioricategories grant universality and necessity to physics, but still retain theReichenbachian view that some historically changing structure might beconstitutive of important physical theories (Friedman 2001).

According to DiSalle, this kind of Kantian Foundationalism is to beinterpreted at the same time as an inquiry into the right that physics has to

2 See Craig 2001.3 See Dorato 2001.


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address metaphysical questions (DiSalle 2006). This is why DiSalle, certainly by making some violence to Kant, also attributes him what for me should beregarded a distinct, fifth position, amounting to the claim that

physics is not a consequence of the metaphysics of nature. Quite simply it is themetaphysics of nature. The metaphysical concepts that we find in physics body, force, motion, space, time, become to us intelligible precisely, and only,as they are constructed by physics itself; physics provide us with the only intelligible notions we have on this matter. (DiSalle 2006, p. 60)

This fifth position, which we could callPhysical Autonomy , is the claim that physics, being itself a metaphysics theory of nature, does not need any metaphysical analysis or intervention from outside. The reason why physics is a metaphysical theory of nature is given by the fact that it aspires to describereality: as Einstein wrote to Schrdinger, the true difficulty lies in the fact that physics is a kind of metaphysics. Physics describes reality. But we dont know what reality is unless we describe it with physics (Allori et al. 2005, p.13).

Let us now pass to comment those options that are nowadays still regardedas alive, in particular Tolerance and Physical Autonomy.

2. TOLERANCE, DISTORTION AND THE COMPATIBILITY TEST WITH PHYSICS

2.1. Contemporary analytic metaphysic is replete with attempts at gaining some precise explications of notions like substance, event,

persistence, object, sameness, identity, becoming, properties, disposition,causation, etc. All these investigations proceed, in many cases at least, in waysthat are completely independent of what is taking place or has taken place within physics. For this reason, such investigations seem to belong to the kindof approach to metaphysics that I have named Tolerance.

Are these researches relevant for a deeper understanding of physics? Theanswer seems to be in the negative, whenever these inquiries do not even feelthe need to confront their theories with physics. This autonomous

metaphysical theorizing is certainly interesting and worth-pursuing, but alsocontains the danger of sterility and isolation. Of course, I would not be ready todeny that, say, understanding the nature of causation, is important for its ownsake; what is less clear, however, and still open to philosophical debate, is whether causation has any role in theobject language of physics, rather than


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being important in a purely pragmatic or explanatory sense.4 Here is how Norton put it in 2003: Mature sciences, I maintain, are adequate to account for their realms without need of supplement by causal notions and principles(Norton 2003, p. 2). The idea here is that in physics the notion of law replacesthe notion of cause5, even though the latter notion has still an important role in helping us to recover old, approximate theories from newer ones (say, Newtons cause of free fall, invoking a force, from the contemporary geometrized theory of gravity).

In conclusion, I would like to put forward the following claim:if it is not clear yet in what sense the notion of property or cause or object can affect, and play a role in physics, a confrontation with physics looks dubious or suspicious , and this is the main reason why many metaphysical inquiries withinthe analytic tradition remain, and possibly ought to remain, safely within thetradition of aut onomy, with all the dangers that such an autonomy involves.

2.2. Another instance of tolerance, sometimes masked under theinvitation to coming to terms with real physics, is what I could calldistortion. This occurs when the confrontation with physics is only apparent ,since the kind of physics that is invoked is either distorted or highly simplified.This sort of uses of a non-actual physics on the part of the analyticmetaphysicians is what Ladyman and Ross criticize in various parts of their book, w hen they refer, for example, to the alleged physically - basedopposition between atomism and gunkism (the view that matter is infinitely divisible):

it is preposterous that in spite of the developments in the scientificunderstanding of matter that have occurred since [Descartes], contemporary metaphysicians continue to suppose that the dichotomy between [partless]atoms and gunk remains relevant, and that it can be addressed a priori.(Ladyman and Ross 2007, p. 20)

This sort of appeal to an imagined physics really counts as an instance of Tolerance, especially if the method of inquiry continues to be wholly a priori .

4 See the debate between Norton (2009) claiming that physics does not need causation andFrisch (2009) trying to argue for the opposite claim.

5 For the relation between causation and law, see, among other texts, Dorato 2005 and Psillos2002.


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2.3. One way in which a confrontation between metaphysics and physicsreally does occur, on the contrary, is when physical theories are invoked as a sort of experimenta crucis to decide between two or more competing metaphysical views: if one of the metaphysical theories is in conflict with physics, it ought to be abandoned. An instance of this use of physics within thecommunity of analytic metaphysicians is given for instance by the dispute between presentism and eternalism, namely between the view that only the present exists (presentism), and the view that past, present and future eventsexist on a par in a block universe (eternalism).

Interestingly, there are people nowadays who claim that this dispute is not genuine (Dolev 2006, Dorato 2006a, Savitt 2006). But let us assume, for thesake of the argument, that there is a genuine debate just in conceptual andmetaphysical terms, and let us assume that this holds also for another debate with respect to which the special theory has been invoked as a decisive test,namely the problem between endurantists and perdurantists. I quote from anabstract of a recent article:

There are two main theories about the persistence of objects through time:endurantism and perdurantism. Endurantists hold that objects are three-dimensional, have only spatial parts, and wholly exist at each moment of theirexistence. Perdurantists hold that objects are four-dimensional, have temporal parts, and only partly exist at each moment of their existence. In this paper weargue that endurantism is poorly suited to describe the persistence of objects ina world governed by Special Relativity. (Hales and Johnson 2003)

Clearly, the meta-philosophical principle, in both of these cases, is that if a

metaphysical theory is not compatible with, or is not properly suited to adapt itself to, a physical theory, we should abandon it. However, note that also inthese cases, the metaphysical debate is somewhat completely external to physics : the solutions to the question whether the future is real or not, or to the problem how entities persist, seem quite unrelated to what physicists nowadaysare really after. These metaphysical problems, in other words, are external to,and independent of, the issues that are really debated within physics. This is why also this type of relationship between physics and metaphysics, I take it,

fully belongs to the philosophical style that I referred to asTolerance .


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3. THE METAPHYSICS WITHIN PHYSICS AND THE NATURE OF INTERPRETATION

Taking stock from Einsteins quotation above (physics is a type of metaphysics), or DiSalle (physics is the metaphysics of nature), I would liketo sketch a view of the relationship between metaphysics and physics that regards the former as being strictly dependent on the latter. If the essential task of the philosopher of physics isinterpreting physical theories i.e., 1) coming up with a precise and exact ontology to associate to the language and formulasof physical theories and 2) relating such ontology to the world of ourexperience it then seems that 1) necessarily involves a metaphysical task,namely finding out how the world can be likeif our physical theories are at least approximately true. Note that this interpretation of the interpretation of physics (which has variously defended by van Fraassen 1980, Giere 1988 andLange 2002) does not require truth from our physical theories, but can beembarked upon also by instrumentalists, since the whole interpretative task rests on a conditional statement (if the theories are at least approximately true).

For instance, can the non-local correlations presupposed by entangledstates be interpreted as referring to some sort of causal correlations? And if theanswer is in the positive, which model of causation do they allow? When we ask such questions, it is of the utmost importance to remark that we can neverexclude that one of the novelties of the whole worldview suggested by EPR-Bohm correlations lies just in the fact that no causal explanation is really fit toexplain/interpret them, because these correlations are to be regarded asfundamental, or natural in Aristotles sense, andas such they need no causal explanation whatsoever (Fine 1989). In other words, without taking stance inthis complicated problem, here we simply want to suggest that sometimes theold, metaphysical notions (causation, property, dispositions) may be unfit to give an account of the new ontology suggested by a physical theory. In ourexample, this sort of possibility makes all attempts of looking for a causalinterpretation of the correlations in question look outdated.

The same could be true for the dispute between substantivalism andrelationism, a metaphysical debate that might have been appropriate for thetimes of Leibniz and Newton, but simply inappropriate after General Relativity, which is a theory that overcomes the distinction between empty spacetime andmatter by identifying spacetime with a gravitational field (Rynasiewicz 1996,Dorato 2008). In other words, the interpretative task must always be open to


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the possibility that no current or traditional metaphysical category is really appropriate for the new physical theory, so that, one more time, theconfrontation between metaphysics and physics is one between concepts andcategories that are imposed onto the latter from the outside.

As another example, consider the question: can the timelike-separation of events in classical spacetime theories be interpreted as giving rise to a tenselessform of local becoming ? Philosophers who have recently defended thisminimalist interpretation (Savitt 2002, Dieks 2006, Dorato 2006b) are wellaware that the question remains whether such a metaphysical reading of relativity is capable of connecting with, or explaining, the sense of passage of time typical of our experience. If this second explanatory task is not fulfilled by postulating a becoming of events defined as their timelike succession in the partial order defined by special relativity, the first ontological interpretationmust be abandoned or at least corrected. This is why the ontological question posed by 1) is relativity theory (special and general) interpretable as a theory that metaphysically admits of becoming? can never be divorced from thequestions raised by 2), namely the connection with our experience.

In conclusion, I would like to stress that it is the connection of themetaphysical interpretation of a physical theory with our experience that givesus the final test for the plausibility of a proposed metaphysical interpretation.This is particularly evident in some interpretations of quantum mechanics, in particular in the no-collapse views linked to Everetts interpretation. In a nutshell, Everetts interpretation solves the measurement problem by denying the reality of the reduction process: the metaphysical interpretation hereconsists in claiming that the fundamental equation governing the temporalevolution of a quantum system is always linear and deterministic. Obviously, inthis case one must solve two correlated problems, both involving an agreement with what we see, and therefore the relationship of the relevant metaphysical posit with our experience. The first problem is why we never perceivemacroscopic superpositions. The second problem consists in trying to explainthe origin of the notion of probability, namely theimpression that the probabilities involved by the Born-rule play a fundamental role in quantumtheory. The first problem is attacked with the theory of decoherence, whichexplains why we never perceive interferences (from within the same world)of Schrdingers infamous dea d cat with its alive counterpart, even though all possible measurement outcomes do realize. This means that there is a world in which the cat is dead and looks dead, and a world in which the cat is alive, and


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looks alive, but in any of these two worlds macroscopic interferences are neverobserved, due to decoherence processes. In other words, the final state is still a macroscopic superposition of different worlds, even though this state cannot be accessible to our experience. Whether this interpretation is satisfactory is of course dependent also on how the second difficulty is tackled, a difficulty that recently has involved attempts at explaining the notion of probability in a physical theory with decision theoretic strategies of agents (Deutsch 1999, Wallace 2007).

The appropriateness of this interpretation of quantum mechanics of coursecannot be judged in this context. Here it has been presented simply in order toshow the reader how complicated the interpretation of a physical theory really is, and how far more promising a philosophical activity it is if compared withexternal metaphysical theorizing. The question of interpretation is in fact not external to physics at all, at least to the extent that in the past also physicists have asked themselves whether atoms or the ether existed or not; in any casethe need to link the physical picture of reality with the world of our experienceremains one of the main tasks of philosophy of physics (Sellars 1963).6

REFERENCES

Allori, V., Dorato, M., Laudisa, F., & Zangh, N. (2005).La Natura delle cose.Unintroduzione ai fondamenti e alla filosofia della fisica . Roma:Carocci.

Craig, W. L. (2001). Time and the Metaphysics of Relativity . Dordrecht:Kluwer Academic Publishers.

Deutsch, D. (1999). Quantum Theory of Probability and Decisions.Proceedings of the Royal Society of London, A455 (1988), 3129-3137.

Dieks, D. (2006). Becoming, Relativity and Locality. In D. Dieks (Ed.),The Ontology of Spacetime (pp. 157-176). Amsterdam: Elsevier.

Dieks, D. (Ed.) (2006).The Ontology of Spacetime . Amsterdam: Elsevier.

6 Of course, I admit that the criteria of what is internal and what is external to physics cannot be left just to the judgments of physicists. Here this difficult question of the normativity of philosophy can simply be mentioned.


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DiSalle, R. (2006). Understanding Spacetime. The Philosophical Development of Physics from Newton to Einstein . Cambridge:Cambridge University Press.

Dolev, Y. (2006). How to Square a Non-Localized Present with SpecialRelativity. In D. Dieks (Ed.),The Ontology of Spacetime (pp. 177-190). Amsterdam: Elsevier.

Dorato, M. (2001).Review of William Lane Craig. Time and Metaphysics of Relativity . Republished (2003) inStudies in History and Philosophy of Modern Physics, 34 (1), 154-158.

Dorato, M. (2005). The Software of the Universe . Aldershot, UK: AshgatePublishing.

Dorato, M. (2006a). The Irrelevance of the Presentism/Eternalism Debate forthe Ontology of Minkowski Spacetime. In D. Dieks (Ed.),The Ontology of Spacetime (pp. 93-109). Amsterdam: Elsevier.

Dorato, M. (2006b). Absolute Becoming, Relational Becoming and the Arrow of Time: Some Non-Conventional Remarks on the RelationshipBetween Physics and Metaphysics.Studies in History and Philosophy of Modern Physics, 37 (3), 559-576. Reprinted in N. Oaklander (Ed.)(2009), The Philosophy of Time , vol. IV (pp. 254-276). London:Routledge.

Dorato, M. (2008). Is Structural Spacetime Realism Relationism in Disguise?The Supererogatory Nature of the Substantivalism/RelationismDebate. In D. Dieks (Ed.),The Ontology of Spacetime II (pp. 17-37). Amsterdam: Elsevier.

Fine, A. (1989). Do Correlations Need to be Explained?. In J. Cushing & E.McMullin (Eds.),Philosophical Consequences of Quantum Theory (pp.175-194). Notre Dame, IN: Notre Dame University Press.

Friedman, M. (2001).Dynamics of Reason . Stanford, CA: CSLI Publications.

Frisch, M. (2009). Causality and Dispersion: A Reply to John Norton.The British Journal for the Philosophy of Science, 60 (3), 487-495.

Giere, R. (1988).Explaining Science . Chicago: University of Chicago Press.


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Hales, S. D., & Johnson, T. (2003). Endurantism, Perdurantism, and SpecialRelativity.The Philosophical Quarterly, 53 (213), 524-539.

Ladyman, J., & Ross, D. (2007).Every Thing Must Go: Metaphysics Naturalized . Oxford: Oxford University Press.

Lange, M. (2002). An Introduction to the Philosophy of Physics . Oxford:Blackwell.

Norton, J. D. (2003). Causation as Folk Science.Philosophers' Imprint, 3 (4).

Norton, J. D. (2009). Is There an Independent Principle of Causality in

Physics?. The British Journal for the Philosophy of Science, 60 (3),475-486.

Psillos, S. (2002). Causation and Explanation . Acumen & McGill-QueensUniversity Press.

Rynasiewicz, R. (1996). Absolute versus Relational Space-time: An OutmodedDebate?. Journal of Philosophy, 43 (1), 279306.

Savitt, S. (2002). On Absolute Becoming and the Myth of Passage. In C.Callender (Ed.), Time, Reality & Experience (pp. 153-167).Cambridge: Cambridge University Press.

Savitt, S. (2006). Presentism and Eternalism in Perspective. In D. Dieks (Ed.),The Ontology of Spacetime (pp. 111-127). Amsterdam: Elsevier.

Sellars, W. (1963). Science, Perception and Reality . London: Routledge andKegan Paul. Republished (1991) by Ridgeview Publishing Company.

Van Fraassen, B. (1980).The Scientific Image . Oxford: Clarendon Press.

Wallace, D. (2007). Quantum Probability from Subjective Likelihood:Improving on Deutsch's Proof of the Probability Rule.Studies in History and Philosophy of Modern Physics, 38 (2), 311-332.


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String Theory: Physics or Metaphysics?Gabriele Veneziano *

[email protected]

ABSTRACT

I will give arguments for why the enormous progress made during the last century on understanding elementary particles and their fundamentalinteractions suggests strings as the truly elementary constituents of Nature. I will then address the issue of whether the string paradigm can in principle befalsified or whether it should be considered as mere metaphysics.

1. THE CENTURY OF PHYSICS?

Very likely the 20th century will go down in history as the century of physics.In my opinion no other field of human knowledge has undergone, in that century, so much progress and so many revolutionary changes. Its very beginning was marked by three developments that shook forever as many scientific beliefs:

The belief inabsolute determinism when, in 1900, Max Planck, in orderto eliminate an infinity in the energy emitted by a black body,

introduced a constant,h , that still carries his name. This marked the beginning of the quantum revolution whose indeterminism was nicely embodied later in Heisenbergs uncertainty principle,

, (1)that bounds from below the product of position and momentumuncertainties.

The belief inabsolute time when, in 1905, Albert Einstein, starting

from the invariance of the speed of light in vacuum,c , introducedSpecial Relativity and his much celebrated relation between mass andenergy:

* Collge de France, Paris; Theory Division CERN, Geneva


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= 2 (2) The belief in anabsolute geometry when, only ten years later, again

Einstein formulated the theory of General Relativity according to whichmatter curves spacetime and bodies simply move along geodesics(i.e., minimal-length paths) in the ensuing non-trivial geometry. InGeneral Relativity Newtons consta nt, G , controls the amount by whichmass and energy affects the surrounding geometry of spacetime.

These three breakthroughs fed all subsequent developments of that branchof 20th century physics that aims at uncovering the laws of physics at theirdeepest level. In particular, the efforts made in the twenties and thirties tocombine Quantum Mechanics and Special Relativity led physicists toformulate, in the forties, a very successful framework known as Quantum FieldTheory (QFT). The first successful application of QFT was QuantumElectrodynamics (QED for short), a theory describing electromagnetic phenomena at the quantum level with incredible accuracy (better than 10 partsin a billion in the case of the anomalous magnetic moments of the electron andthe muon).

During the fifties and the sixties physicists tried to extend that framework to the description of two of the other known forces, the strong (or nuclear)force, responsible for binding protons and neutrons inside the atomic nuclei,and the weak force, responsible for radioactivity. Such experimental andtheoretical effort was rewarded in the early seventies when physicistsformulated the so-called Standard Model of elementary particles, a milestonethat will certainly stay in the books of physics. Many tests of the StandardModel, carried out in the seventies, eighties, and nineties, have so farconfirmed the validity of the Standard Model with no exception (the discovery that neutrinos do have mass can be easily incorporated in the S

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Humana_Mente 13 Physics and Metaphysics