donald davidson - lawa and causes

7/30/2019 Donald Davidson - Lawa and Causes

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Laws and cause*Donald DAYIDSON..

AbstractAnomalous Monism is the view that mental entities (objects and events) are identical withphysical entities, but that the vocabulary used to describe, predict and explain mental events isneither definitionallynor nomologically reducible to the vocabularyof physics. The argumentfor Anomalous Monism rests in part on the claim that everytrue singular causal statement re-lating two events is backed by a law that covers those events when those events are appropri-ately described. This paper attempts to clarify and defend this claim by tracing out some con-ceptual relations among the concepts of event, law, and object.

In her inaugural lecture as Professor of Philosophy in the University ofCambridge,G.E.M. nscombe examined the often declared or evidentlyassumed view thatcausalityis some kind of necessary connection, or alternatively, hat being causedis- on-trivially- nstancing some exceptionlessgeneralizationsaying that such an eventalways follows such antecedents.

She complained that the truth of thisconception ishardly debated, andsurveyed its history from Aristotle to the then present to make her point.I have the honor of bringing up the rear: even Davidson, she remarks in herlast paragraph,

will say, without offering any reason at all for saying it, that a singular causal state-ment implies that there is such a true universal proposition.I offer this paper as part of the much deserved celebration in honor of Henri Lauener,valued contributor, and formidable champion of, international philosophy, thoughtful andwtty companion, steadfast and affectionate friend.I wish to thank David Albert and,Noa Latham for their help. The central idea in this paperhasa Kantian ring, and wasused by Gordon Brittan in his Kants Theoryof Science, PrincetonUniversitv Press. 1978. As he Eenerouslv notes, he first heard the idea in mv classes at Stand-ford U$iersity. IThe Universitv of California at Berkelev, USACuusuiityan8Determination,Cambridge University Press, Cambridge, 1971, p. 1.Ibid., p. 29.

Dialectica Vol. 49, No -4 (1995)


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264 Donald DavidsonIn the paper to which Anscombe refers,3 I offered no reason for sayingtrue singular causal statements (like The eruption of Vesuvius in 79 A.D.

caused the destruction of Pompeii) imply the existenceof laws that cover thecase, nor did I offer any in my subsequent article Mental Events. I wrotethere that I was treating this relation between the concepts of law and cause asan assumption, observing that even someone who was dubiousof the assump-tion might be interested in an argument claiming to show that the assumption,along with other commonly held (though debated) premisses, implied a formof monism - what I called Anomalous Monism.Various critics have joined me in noting that if the assumed relation be-tween laws and causality (which in Mental Events I called, rather windily,The Principle of the Nomological Character of Causality) s false, the argu-ment for anomalous monism fails, and some have enjoined me to produce areason to accept the assumption. Others, like Anscombe, have expresseddoubt that the assumption is true. I have to doubt Davidsons. . .premise,that all pairs of events related by cause are subsumed under laws, writesJennifer Hornsby.s Ernest Sosa asks, Why must there always be a law tocover any causal relation linking events x and y? What enables us to assumesuch a general truth?6 Qler Burge is more skepticalstill: I do not think it apriori rue, or even clearly a heuristic principle of science or reason, that cau-sal relations must be backed by any particular kind of law.Burge is right that if there is a reason for holding the cause-law thesis, theargument must in some sense be a priori, for the thesis clearly is not a pro-nouncement of ordinary logic, nor can it be established empirically,anegativepoint on which Hume and Kant were agreed. To say the cause-law thesis is apriori is not, of course, to say that particular causal laws are a priori. If thethesis s true, what we know in advance of evidence is that if a singular causalclaim is true, there is a law that backs it, and we can know this without know-ing what the law is.

Causal Relations,The Journal of Philosophy, 64(1967 ): 691-703 . Reprinted in Es- irst published in Experience and Theory, L. Forster and J.W. Swanson, eds.,TheWhich Mental Events are Physical Events?,Proceedings of the Aristotelian Society,Ernest Sosa, Mind-Body Interaction and Supervenient Causation, in Midwest

Philosophy of Language and Mind: 950-1990, in The P hilosoph ical Review, 101

says on Actions and Events, Oxford University Press, 1980.University of Massachusetts Press, 1970; reprintedin Essays on Actions and Events.1980-81, p. 86.Studies in Philosophy, IX , 1984, p. 278.(1992), p. 35.


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Laws and cause 265I.

The cause-law thesis needs to be made more definite. By a singular causalstatement I mean a statement that containstwo ingular terms (names or defi-nite descriptions) referring, or purporting to refer, to events, joined by someform of the verb to cause (if the statement is expressed in Enghsh). Ofcourse other verbs can do the same work, for example produce, resultin,haveas consequence,etc. Examples of singular causal statementsare:Hislighting the match caused the explosion, The next California earthquakewill cause the destruction of the Golden Gate Bridge, The hurricane is thecause of the rise in the water level. The hurricane caused the water level torise is not, however, a singular causal statement, since the water level torise is not a singular term; this last sentence says only that the hurricane (aparticular event) caused at least one event that was a rising of the water level.The rise purports to pick out a particular event; a rise marks a generalexistential claim without implying singularity.Singular causal statements are extensional: their truth value is invariantunder the substitution of one name or description of an event for anothername or description of the same event. Thus if Socrates was Xanthippes hus-band, and Socrates drinking the hemlock resulted in Socrates death, it fol-lows that Socrates drinking the hemlock resulted in the death of Xanthippeshusband. The point may seem obvious, and indeed it is; yet it has escaped allthose who have been tempted to thi nk that if singular causal statements implythe existence of a covering law, they must imply, or somehow indicate, someparticular law that covers the case. It is easy to see why this does not follow.Given the endless possibilities for redescribing events (or anythmg else) innon-equivalent terms, it isclear that there may be no clue to the character ofan appropriate law in the concepts used on some occasion to characterize anevent. What may be the case is that if a singular causal statement is to be ex-planatory in some desired sense, it must put its hearer in mind of at least thegeneral nature of a relevant law. It also may (or may not) be the case that theonly, or best, reason for believing a singular causal statement is evidence forthe truth of some law that covers the case. But such epistemological and ex-planatory issues, however we resolve them, ought not lead us to color singularcausal statements intensional.In formulating the cause-law thesis, what should we count as a law? Lawsmust be true universally quantified statements. They also must be lawlike:they must support counterfactuals,and be confirmed by their instances (theseconditions are not independent). To quallfvas strictly lawlike, they shouldcontain no singular terms referring to particular objects, locations or times


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266 Donald Davidson(strictly lawlike statements are symmetric with respect to time and location).Strictly lawlike statements do not contain open-ended phrases like otherthings being equal, r under normal conditions. It must be admitted thatsuch phrases are, tacitly or explicitly, part of the content of many legitimatelaws; thus many laws are not strict, including the laws peculiar to such sciencesas geology, biology, economics, sociology and psychology.The distinction between strict and non-strict laws is essential to the argu-ment for Anomalous Monism. The argument for Anomalous Monism hasthreebasic premises: (1)there are causal relations between events describedasphysical and events described asmental, (2) there are no strict laws relatingevents under physical descriptionswith events under mental descriptions, and(3) if two eventsare related as cause and effect, there is a strict law coveringthe case.The first premise I took tobeevident: events in the world we describein physical terms cause and are caused by thoughts. The second premise Ihave defended at some length, mainly on the grounds of the uneliminablynormative or rational aspect of intentional idioms, and the consequent irredu-cibility of mental concepts to concepts amenable to inclusion in a closed sys-tem of laws. The argument went thisway: It is plausible that there is a set ofconcepts (perhaps there aremany suchsets) which lend themselves to the for-mulation of a closed causal system. Let us callthese concepts the concepts ofphysics. In t h i s case, for any two events related as cause and effect, therewillbea strict law, i.e., a physical law, covering the case.Since mental concepts arenot amenable to inclusion in a closed system, the strict laws covering singularcausal relations expressed in (at least partly) mental terms must also be ex-pressible in physical terms. Hence events described in mental terms must alsobe expressible in physical terms: in ontic language, mental events are identicalwith physical events. It follows that mental concepts are supervenient onphysical concepts, in this sense: if two events fail to share a mental property,they wiU fail to share at least one physical property.

Anscombe, as we have seen, attacked the view that causes necessitatetheir effects, and she explainedthisas requiring a law that isan exceptionlessgeneralization saying such an event always follows such antecedents. Thenotion of necessity comes in, I suppose, with the idea that one candeduce astatement of the existence of the effect from a statement of the cause and theappropriate law. Anscombe takes this to forbid the indeterministic laws ofquantum physics. The constraints I have put on the laws that the cause-lawthesis says exist do not, however, disallow probabilistic laws. Such laws areuniversal and are exceptionless (the probabilities they predict have no excep-tions). So it ispossible, though unlikely, that Anscornbeis not questioning thecause-law thesis as I have stated it. (We do disagree on a consequence of


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Laws and cause 267allowing probabilistic laws, since she holds that such indeterminism leavesroom for a meaningful concept of human freedom, while I thi nk the indeter-minism of quantum physics cannot facilitate, though it might conceivablysometimes frustrate, freedom of action).Since it allows probabilistic laws, the cause-laws thesis does not (in onefairly standard sense of that messy concept) imply determinism. Neither,then, does it imply complete predictability, even in principle, nor retrodicta-bility.

II.In the Enquiry Concerning Human Understanding,Hume defines a causeto be an object, followed by another, and where all the objects similar to thefirst are followed by objects similar to the second. If we thi nk of this as astipulative definition, then one condition for the existence of a law, gener-ality, is built into Humes definition. But if the definition is intended as ananalysis of the common onceptionof cause wecan,with Anscornbe, ask if itiscorrect. It is in any case clear that his definitionwillnot satisfy the cause-law thesis, since it fails to distinguish true but non-lawlike generalizations ofthe night-day sort from lawlike generalizations. Not that nothing Hume says

invites us to observe this distinction; his discussion of induction requires it.Humes definition of cause ust quoted says that the truth of a singular causalstatement depends on he existence of a true generalization that covers notonly the case at hand, but all other cases, observed and unobserved, past,present and future.This raises the obvious question what justifies us in be-lieving in the truth of such a generalization, and therefore in the truth of anysingular causal statement. Humes answer, as we know, is that nothing jus-tifies us in eitherbelief;but then we are left to wonder why we have any suchbeliefs. For this Hume does have an answer, the gist of which is given by hisalternative definitionof cause: a cause is an object, followed by another,and whose appearance always conveys the thought of that other. Here, asthe always makes clear, anobject stands for a classof objects. Althoughthis pronouncement has invited many interpretations, I will take it here toimply at leastthis:we believe that one event has caused another if every eventthat seems similar to the first iiasbeen followed by an event that seems similarto the second. It adds something to say (as Hume does) that this pairing ofsets of events or appearancesis a habit of the mind, for this implies a disposi-tion present even when not at work, a disposition to project the pairing be-yond what hasbeen given. We expectfire to burn and bread to nourish in thefuture.


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268 Donald DavidsonNelson Goodman, in his basic book Fact, Fiction and Forecast8,praisedHume for realizing that only human tendencies to class@ and associateinone

way rather than another could be called on to characterize inductive reason-ing, but he criticized Hume on two grounds. The first was for thinking this ap-proach is skeptical; in Goodmans opinion induction does not need justifica-tion, only a correct, naturalistic description. The second was that even takenas description, Hume missed the difficulty that lay hidden in the concept ofsimilarity. Goodman brought this out by inventing the predicate grue.Something is grue if examined before some future time t and found to begreen, and otherwise is blue. We have no trouble understanding this predi-cate; it is defined in a straightforwardway in intelligible terms. We can there-forerecognize things that are grueassimilar: the predicate grue is true of allof them; they are alike in being grue! Yet we realize that All emeralds aregreen is, if not true, at least lawlike, whileAllemeralds are grue cannotalsobe lawlike if induction is to provide any guidance to the future. Even if weabandon the search for an ultimate justificationof our inductive practices, it islegitimate to ask what those practices, at their reflective best, are.The conceptof similarity cannot, by itself, cany he burden of distinguishing the lawlikefrom the non-lawlike.Is it quite right, though, to say Hume let matters rest with the unquestionedconcept of similarity? According to Goodman,

The real inadequacy of Humes account lay not in his descriptive approach but in theimprecision of his description. Regularities in experience, according to him, give rise tohabitsof expectation; and hus it is predictions conforming to past regularities that arenormalor valid. But Hume overlooksthe fact that some regularities do and som e do notestablish such habits; that predictions based onsom e regularities are valid while predic-tions based onother regularitiesarenot. . Regularity in greenness confirmsthe predic-tion of further cases; regularityin grueness does not. . .Regularities are where you findthem, and you can find them anywhere.If we take Humes first definitionof cause,this criticism is apt. But Humesreformulation defines cause in terms of the inductions we actually make, notthose we might have made had we been differently constituted. When Hume

writes that after a repetition of similar instances, the mind iscarried by habit,upon the appearance of one event, to expect its usual attendant, and to be-lieve that it will exist o we notice that similar and usualare uncritically

First published in 1979. Page numbers here arefrom the fourth edition,Harvardbid, p. 82.A n Enquiry concerningHuman Understanding,Sect. VIII, Part 11.

University Press, 1983.


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Lawsand cause 269used. But the second definition of cause doesnt employ these words, and maybe viewed instead asdefining the relevant concept of similarity.To take one ofHumes examples: if every time we have observed a certain vibration of astring it has been followed by a certain sound, then the next time we observethat vibration, we expect that sound and not another. The phrases a certainvibration and a certain sound assume the classifications that are appropri-ate to inductions; but we may take the operative expectations to fix the classi-fications. Our expectations or projections thus distinguish the lawlike fromthe non-lawlike. It is true that this account differs from Goodmans in severalways, but not, ashe suggests, in that Hume provides no answer at all to Good-mans New Riddle of Induction.

Goodmans analysis is, of course, far more explicit, detailed and precisethan Humes. It also differs in another interesting respect. Goodmans detailedaccount makes the lawlike status of a statement depend on the projectiblestatus of its individual predictions; Humes account rather treats whole state-ments (sentences) as lawlike or not (which depends on present habits asformed by past experience). Thus Humes analysis allows that a generaliza-tion of the form AllFs are Gsmay be lawlike and AllFs are Hs not,even though Hmay occur in other statements that are awlike. In other words,with respect to things that are F, G may be a projectible predicate, while withrespect to things that are F, H may not be projectible. Goodmans analysisdoes not allow such cases, since forhim projectibility is a property of predi-cates, not of predicaies relative to other predicates. In this respect I thinkHumes line superior, for reasons I shall presently discuss. l1

111.Hume says (though not with complete consistency) that we believe in acausal connection between two events only when we have experienced re-

peated conjunctions and no exceptions (Im not bothering with the furtherconditions of succession and contiguity here). It is therefore worth pointingout that the cause-law thesis is not committed to this idea. Nor is it committedto the view that the only way of supporting or confirming a singular causalstatement is by reference to relevantly similar cases. I am with those philoso-phers (for example Anscombe, Ducasse and McDowell) who th nk Humewas wrong in supposing we never directly perceive that one event has causedanother, even when we have no supporting evidence drawn from similarcases.

l1 I made this point, perhaps too crudely, in Mental Events.


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270 Donald DavidsonJohn McDowell recognizes that I do not thi nkcausal laws aremerely truegeneralizations (though as I say above, neither do I thi nk this is all there is to

Humes view), but he argues that if we give up this reduction, it is hard to seewhy we should accept the cause-law thesis, which McDowell considers part ofthe broadly Humean picture of causation.In other words, McDowell holdsthat if we give up Humes epistemic claim that the only evidence we have forcausal connections is observed regularities, it is hard to see what now holdsthe [broadlyHumean] icture of causation in place.Humes own recommendation of it is, in effect, that since singular causal relations

are not given in experience,there is nothing for causation to consist in but a suitablekind of generality. And this recommendation seems nextricably bound up with a dual-ism of scheme and content, of organizing system and something waiting to be or-ganized, the untenabilityofwhichDavidson has done asmuchasanyone to bring hometous.Without that dualism, there is no evident attraction left in the thought that singu-lar causal relations are not given in experience. 2

The connection with scheme-content dualismisobscure to me, but it is anycase irrelevant, since I have never claimed that singular causal relations arenot given in experience. The notion of being given in experienceis not onefor which I have felt much need, n this context or any other. But if it meanshere no more than that the excitation of our senses may sometimes cause uscorrectly, justifiably and without inference to believe that a particulareventhas caused another, then I certainly accept that singular causal relationsareoften given in experience. 3 McDowell apparently holds that once we grantthat it is possible to perceive that one particular event has caused anotherthere is no reason to accept the cause-law thesis. But why should we assumethis particular connection, or non-connection, between an epistemic and anon-epistemic issue?C.J. Ducasse believed that a true singular causal statement entails theexistence of a general law, and that it is possible to observe that one event hascaused another without havingany independentreason o accept a generali-zation.He held thatallknowledge of causality depends onobserving particu-lar cases, though if we knew that an event c causedan event e in a situationS,we would then know that any event exactly like cwould causeanevent exactlylike e in a situation exactly like S.Unfortunately,his argument for thisviewseems o rest on wo confusions that he elsewhere warns against: the confu-

JohnMcDowell, Functionalism nd Anomalous Monism,inActions and Events:PeRpCctiws on the Philosophy of Donald Davidron, E. -re and B.McLaughlin, eds.,Blackwell, Oxford,1985,p. 398.The innerquote from Davidson is from Znquiries into Tiuthand Interptetation,Oxford University Press, 1984,p. 189.* This has always been my view. See Actions,Reasons and Causesin Essays on Ac-tions and Events, p. 16.


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Lawsand cause 271sion of particular events with events of the sametype,and the idea that theconcept of a sufficient conditioncanbe applied to eventsaswell as to senten-cesabout, and descriptions of, events. l4 What I find of interest for my presentpurpose is his definition of cause.Ducasse tells us that he performed the following experiment with hisstudents: He would put a paper-covered cardboard box on his desk, and askthe students to keep their eyeson t. He would then place hishand on he box,and the end of the parcel facing the students would instantly glow. Ducassenext asked them what caused the box o light up when it did, and they wouldall naturally answer that the glowingwas caused by Ducasses placing his handon he box. l5 Ducasse notes that the experiment was not repeated, no similarcaseswere offered for observation. He allows that the students might have thecause wrong; his point was only to establish something about their criteria forjudging what had caused the package to glow.O n he basis of a single experi-ment, they believed there was a causal connection,as,of course, there was.This leads Ducasse to the following definition of cause: if cis he only changein a situationSwhich precedes the only subsequent change e inS, hen cis thecause of e. This ormulation is mine, and it does not do full justice to Ducassesmore guarded definition. My formulation does, however, bring out a difficultyDucasse understandably overlooked. He did not pause to ask what con-stitutes a change, and therefore what sorts of entities could count as causesand effects.A natural first stab at saying what a change is goes something like this:some predicatePis true of an object or situation at a given time, t, and subse-quent to tPis no onger true of that object or situation. If somethingisgreen,and then isblue, this s a change, an event. If an emerald before oureyes wereto turnblue after being green,we would seek an explanation of such event,some other change that caused the observed change. Our first stab at defininga change or event would appear to work. But wait: if an emerald were to staygreen as time t ticked past, it would have changed from grue to bleen (some-thing is bleen if observed before time t and is blue, and otherwise is green).The predicate grue would not have stayed true of it, for it would have cometo instantiate the grue-excluding predicate bleen. Ducasse did not, as farasI know, suggest my first stab at defining a change or event, but neither didhe volunteer any altemative.16 Without some idea of what constitutes a

l4 Ducassesmostextended discussionof causality is in his Nature, Mind and Death,TheIs Ibid., p. 95.l6 Lawrence Lombarddoes seem to haveacceptedmy first stab.Seehis Events nd

Open Court Publishing Co.,La Salle, Illinois,1951.Their Subjects,Pacific PhiZosophicuZ QuarterZy 62(1981), p.138.


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272 Donald Davidsonchange,hisanalysisof cause in terms of only change leaves us up in the air.Of course one thing that is green is similar to something else that is green; theyare the same color. But this is no help. If grue and bleen arent colors, let us callthem tolors- a property is a tolor if it changes color at time t. Then onething that is grue is similar to something else that is grue; they are the sametolor.

There is an obvious correspondence between Humes problem and Du-casses problem. Humes problem was the problem of relevant generality; heneeded o be able to say when one event was relevantly similar o another inorder to distinguish lawlike generalizationsfrom non-lawlike ones. Ducassesproblem looked at first unrelated, since it apparently concerned particularcases; it arose in the courseof trying to define cause in a way Ducasse thoughtwas totally at odds with Humes approach, a way that makes no appeal toother cases. But in fact Ducasses definition of the causal relation has no con-tent unless we are able to distinguish changes form non-changes,17 and thisdistinctionturns out to involve generality in the sense that it is just the predi-cates which are projectible, the predicates or properties that enter into validinductions, that determine what counts as a change.The underlying problem is in both cases the same: neither Hume nor Du-caSse has specified when cases are relevantly similar. Hume needs to say whenone change is relevantly similar to another (Same cause, same effect); Du-casse needs to be able to say when one state is not relevantly similar to an-other, i.e., when a change or event occurs.ThusHumes and Ducasses defini-tions of cause, soapparently odds, are essentially equivalent. Hume says that ccaused eif and onlyif every event similar to cis followed by an event similar toe, that is, if and only if every event that is d ike is followed by an event that iselike. Ducasse says c caused e f and only if e is the only change that followedc, and cis the only change preceding e. Suppose the c-like event is the strikingof a particular match and the elike event the lighting of that match. A n eventis clike if it is a striking of a match and elike if it is the lighting of a struckmatch. According to Hume, c caused e if and only if every clike event is fol-lowed by an elike event. According to Ducasse, c caused e f and only if cwasthe only change in a situation in which e was the only change that immediatelyfollowed. But cwas the cause of eonly if cand ewere the relevant changes, and

l7 Ducasse ounts unchangesaswellas changesas events, but this terminological pointis unrelated to the problem he faces in distinguishing events that are changes form events thatareunchanges. In thisessay, I do not follow Ducasses terminology: I call only changes events.


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Laws and cause 273they were this only if cwas a change from not being struck to being struck, i.e.,a clike event, and e was a change from not being alight to being alight, i.e.,was an elike event.This is the case, Ducasse argues, if and only if every eventthat is clike is followed by an event that is elike. These formulations arecrude, but they serve to bring out the central fact that it is only if clike andelike are the right sort of predicates, when taken together, that the quotedgeneralization-schemata are, if true, laws.

It is not surprising, then, that singular causal statements imply the exist-ence of covering laws: events are changes that explain and require such expla-nations. This is not an empirical fact: nature doesnt care what we call achange,sowe decide what countsas a change on the basis of what we want toexplain, and what we thnk available as an explanation. In deciding whatcounts as a change we also decide what generalizations to count as lawlike.If the Big Bang left behind a uniformly expanding universe, we should ex-pect that as we expand along with it, the intensity of the background micro-wave radiation will be the same in all directions. It is not; the radiation ismeasurably stronger in one direction than in others. This has been explainedby assuming that the difference is due to the motion of our galaxy relative tothe general expansion. Subsequent observations revealed, however, that overa vast area all neighboring galaxies are moving with us towards a commonspot in the sky. This was in turn explained by the hypothesisof some immensebut unobserved mass at that spot (the great attractor). In December of1993,careful studies of the motion of galaxies four times further out in spacethan had previously been studied showed that they too were travelling in com-pany with the rest through the background radiation at about 500kilometers asecond. Nothing has turned up that isnt moving with the crowd. Soeither theuniverse is uneven on a far larger scale than had been supposed or explainedby present theory, or else the background radiation does not provide a truerest frame. In that case, says Princeton astrophysicist Bohdan Paczynski,theres something wrong with our prior definitionof what is at rest and what ismoving. Exactly: if you cant explain it using one assumption of what countsas a change, adopt new categories that allow a redefinition of change.The historyof physics is replete with examples of such adjustments in thechoiceof properties to define change, thus altering what calls for a causal ex-planation. At a certain level of common-sense physics, nothing is more staticthan a rock in the desert (unless, of course, someone picks it up, at which pointthe causeof its change of position is obvious, and a rough law surfaces). Even

Asrelatedby FayeHam,Galaxies eep GoingWith the HOW,cience, 259(1993),p. 31.


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274 Donald Davidsonuntutored observation may note a change in the temperature of the rock, butthis is geared to an even more noticeable change in the relation of the sun tothe rock. More serious science discovers changes in the positions of invisibleparticles in the rock which take place independent of changes in temperature;recognition of these changes allows for the causal explanation of a fa r largerrange of phenomena.

One way science advances is by recognizing change where none was seenbefore. It can also work the other way around. Galileosparked a revolution-ary improvement in physics when he proposed that uniform rectilinearmo-tion not be treated as a change requiring an explanation, but as a steady state.The result was to give up the search for a cause of such motion and to treatonly deviations from such motion as changes. Further advances made un-form rectilinear velocity only a special case of uniform acceleration; un-changes took overaneven larger territory with the idea of not treating gravityasa force,so hat the motion of abody along geodesicsasdefined by a spacialframework determined by the distributions of masses in space became a statenot requiring a cause.l9The dispositions o which we advert to explain what happens to objects, orthe things they do, encapsulate the relation between causality and laws. Weexplain why the lump of sugar dissolved when placed in water by mentioningthat it was water-soluble; something is water-soluble if placing it in watercausesit to dissolve. We gain some understanding of why someone flew into arage over a trifle if we know he was irascible; some one is irascible if smallthingscausehim to be angry. The causal powers of physical objects are essen-tial to determining what sorts of objects they are by defining what sorts ofchanges they can undergo while remaining the same object and what sortsofchanges constitute their beginnings or ends. Our concept of a physical objectis the concept of an object whose changes are governed by laws.Itwould, as remarked before, be a large mistake to suppose that every wayof refening to a causeoreffect tells us how to characterize the change in termssuitable for incorporation in a law. Hurricane Andrew is a perfectly goodphrase for picking out aparticular event, but there isnothing in the concept ofa hurricane that allows us to frame precise general laws about the causes or ef-fects of hurricanes. If a hurricane isan event, it isa candidate for causal expla-nation; to say something caused it (the formation of a certain extreme lowpresswearea for example) is to claim that the changes involved can be de-scribed in terms that would serve to formulate a generalcausal law.

l9 My discussionhereisbased inpartonRobert Cumrmns, States, auses, and theLawof Inertia, PhilosophicalStuak, 29(1976): 21-36.


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Laws and cause 275To revert now to the idea that what makes a statement lawlike is not a mat-ter of the projectible character of its individual predicates, but of the appropri-

ate pairing or matching of predicates. Let us ask how projectible Goodmansfavorite projectible predicategreen s. It picks out a class of objects we pro-ject early and easily. AU emeraldsare green is lawlike, until, of course, de-feated by counterexamples. But even if not proven false, it is not a strict law;for when is somethinggreen?We are inclined to say something isgreen f andonly if it looksgreen o normal observers under normal conditions. But looksgreenand normalarenot predicates that canbe sharply defined, and theycertainly cannot be reduced to the predicates of physics. They cannot featurein the laws of a closed system. If we imagine that a satisfactory definition ofemeraldcan be devised in the vocabulary of physics, then green s notstrictly projectible of emeralds. Of course, green s more projectible of em-eraldsthangrue;but greenand blueareonlyasprojectible of emeraldsand sapphiresas grue and bleedareof emerires and sapphalds. This dis-tinction, between predicates like green and grue on the one hand, andpredicates that togethercanfeature in strict laws,is crucial,as I said, to the ar-gument for Anomalous Monism. It is what distinguishes psychophysical lawsfrom the laws of an advanced physics.We areborn,asQuine has emphasized, O treating some pairs of thingsasmore similar than others. We react differentially to sudden loud noises, andsince we do not like such sounds, we soon earn to cringe from what has fre-quently preceded them. Thus long prior to the acquisition of language, oranything that can properly be considered concept formation, we act as if wehad learned crude laws. We are inducers from birth; if we were not, infantmortality would be the rule, if there were any infants. Concepts, concep-tualized laws, the idea of causal relations between events, build on hese foun-dations.In the course of avoiding and seeking, learning to control our envi-ronment, failing and succeeding, we build the lawlike habits that promote sur-vival and enhance life. These laws of action are highly pragmatic not only intheir conspicuous ties to action, but in their breezy disregard of the irrelevantor implausible. The generalizations on which not only the untutored infantbut also our adult selves mostly depend are geared to the normal, theusual. We dont know, and for practical purposes dont care, what wouldhappen if there wereno oxygen, temperatures were to fall to absolute zero, orthere were a black hole in the closet (Inow learn that there may be!). But prac-tical purposes can change, and the conditions at one time happily abandoned

In NaturalKinds,in Ontological Relativity and Other Essays, Columbia UniversityPress, 1969.


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276 Donald Davidsonto ceteris paribus clauses may become relevant, or come to be recognizedasrelevant. We then refine our classifications to improveour laws.

Learning laws of greater generality provides no reason for jettisoning ourproviso-laden work-a-day causal laws. When I flick on the light switch, I haveno reason to reflect on the speed of light, though I may briefly dwell on thatmagic constant when my telephone calls to Perth are relayed - and percep-tibly delayed-by satellite technology. The more precise and general laws are,the less likely it is that wewillbe in a position to employ them in predicting theoutcomes of our ordinary actions or the weather. Our intense interest in theexplanation and understanding of intentional behavior commits us irrevoc-ably to such conceptsasbelief, desire, intention and action; yet these are con-cepts that cannot, without losing the explanatory the power they have whichbindsus to them, be reduced to the concepts of an all-encompassing physics.We have interests that are not practical. There are things we want to under-stand whether or not we cancontrol them and whether or not such knowledgewill serve our mundane needs. Pursuit of the truth in such cases can in prin-ciple proceed without the constraints of practical control and gain. In thismood we can seek laws that have no exceptions.The same strategy that serves to refine our practical lore, the strategy thatleads us to adjust what countsas a change or as requiring a causal explanation,works here too, as s evidentinthe advances in physics due to Galileo, Newtonand Einstein.Robert Cummins puts it this way:

A decision about how to characterize [a statel- a choice of state variables- mposesdistinctions between states and non-states, and hence determines what is and what isnot construedas an effect. Such decisionsare not arbitrary, in part becausethey havethis consequence. Effects requi redirect causal explanation; f there is none to be hadwhich statisfies, hen we shall alter our taxonomy. Thissounds ike metaphysics, and in-deed it is. . .All this presupposes a certain explanatory strategy [which] is easy to statein outline: what requiresexplanation is change, and changes are to be explained as ef-fects, the trick being to characterizematters in a way which makes this possible, i.e., in away which distinguishes genuine changes from states. 21

Cumminsnotes that physics leading up to and including classical mechan-ics and its kin has followed the strategy he describes and adds, somewhatglumly, thisstrategy seems to be breaking down at the quantum level. I amnot up to evaluating every implication of this last suggestion, but I do notthink quantum physics poses a threat to the cause-law thesis. If what Cum-m i n s means is that the ideal of a completely deterministic theory must be

21 bid., p. 33.


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Laws and cause 277given up if quantum physics is the last word, he is of course right. But hisstrategy would seem to apply to quantum physics if we delete the word di-rect from the requirement that effects require direct causal explanation, andunderstand the changes that are to be explainedas sometimes being changesin probabilities.

Thisis the view promoted many years ago by Henry Margenau. He formu-lates what he calls the Principleof Causalityas follows: causality is viol-ated when a given stateA is not always followed by that same state B.22 LikeCummins,he notes that without an understandingof what constitutes a state,this tells us nothing; but that, on he other hand, once we decide what con-stitutes a state, we have decided what counts as a causal law. Why, though,should we count on he there being a way of specifying states that allows theformulation of exceptionless laws? Here is Margenaus answer:

[Wlhenever a physical system does not appear to be closed, that is when the dif-ferential equations describing it contain the time explicitly. ..,we conclude that thevariables determining the statein question are not completely known. We then look im-mediately for hidden properties whose variation may have produced the inconsisten-cies, and whose inclusionin the analysis would eliminate them; moreover if we do notfind any we invent them. This procedure is possible because. . . he term state is un-defined. .. t seems, then, that the causality postulate reduces to a definition of what ismeant by state. 3Forthisreason, Margenau says, physicscannever inform usof a failure ofthe causality principle. Quantum mechanics, he concludes, poses no hreat

to the causality principle; it just once again redefines the concept of a state.Margenau could not, of course, have known about Bells inequality theo-rem, nor the experiments hat made useof it to prove that therecanbe no localhidden variable theory. But Margenau did not understand the Principle of

Causation to require a deterministic physics: he required only that the notionof a state be formulated in such a way as to insure that the laws be strict. Thepoint comes out clearly in a recent discussion of the philosophical fallout fromthe experimental proof of the impossibility of a hidden variable theory:

Complete knowledge of the state of a classical system at a given time is synonymouswith exact knowledge of allobservables at that time. Complete knowledge of the stateof a quantum mechanical system is ensured by the exact knowledge of only a subset ofallobservables at the same time. ..Only when one asks for the value of an observablenot in the complete set of observables that are knowable simultaneously does one en-counter the probabilistic nature of QM. In this sense the probabilistic element enters

22 Meaning nd ScientificStatus ofCausality,PhilosophyofScience, 1(1934), .140.23 hid., pp. 144,5.


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278 Donald DavidsonQM through the measurement process, which is bound to change the observed sys-tem. . .The variouspossible outcomes of such a measurement occur with probabilitiesthat canbe predicted exactly. The outcome of any one such measurement. . . annotbepredicted.

Thus Margenau is borne out: the conceptof a state of a quantum mechan-ical system has been defined to ensure that all that canbeknown about it at amoment completely determines the state. The identity of a quantum state issensitive, in a way that states in classical systems are not, to the effect ofmeasurements. In a classical system, it is assumed that the effectof measure-mentscan in principle be reduced to an arbitrarily high degree, while in quan-tum physics the effect of measurementsis integral to the theory: the measur-ing device becomes part of the same physical systemaswhat is measured, andsubject to the same laws. Quantum mechanics sacrifices determinism as thecost of gaining universality. It states beautifully what iscompletely ignored inclassical physics: through man naturecan observe itself.25 Far from challeng-ing the cause-law thesis, quantum physics exemplifies it.

v.Quantum physics may not, of course, be the last word. It is not only Ein-

stein who dreamedof a theory that would supersede quantum theory, or in ef-fect make quantum theory deterministic. Steven Weinberg, for example, notonly dreamsof aunifiedTheoryof Everything, but speculates that such a the-ory might be completely deterministic. 6 But it is hard to thi nk that the ques-tion whether such a theory exists is a purely conceptual question, at least atheory human beings could, even in principle, invent and test. Surely we mustallow that the best physics that is possible for us is irreducibly probabilistic.Does thismean the cause-law thesis is not tenable? I thi nk not. MargenausPrinciple, essentially Humes samecause,same effect principle, put us onthe track of the idea that natural and devised standards of similarity play afundamental role both in the notion of change and the notion of law.Thispro-vided a legitimate connection between the concept of causality and the con-cept of a law. We can imaginethis connection being tight enough to supportcompletely deterministic laws. Indeed, this is how classical mechanics as-sumed things were. But if physics cannot be made deterministic, if the ulti-

FritzRohrlich, FacingQuantumMechanicalReality, cience,221 (1983),p. 1254.25 Ibid., p. 1253.26 InDreanzrof a Final Theory,Hutchinson,asreportedby JohnLeslie, The Times Llte -mry Supplement,Jan. 29, 1993, p. 3.


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Laws and cause 279mate laws of the universe, so far as we willever know, are probabilistic, thenwe must thinkof causalityas probabilistic. Singular causal statementswill stillentail the existence of strict laws, even at the quantum level, but the lawswillnot m eet Humes or Kants or Einsteins standards.

Dialectics Vol. 49, No 2-4 (1995)

donald davidson - lawa and causes

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