Fundamental Laws and the Completeness of Physics[1]

David Spurrett

(Department of Philosophy, University of Natal, Durban.)

Abstract

The status of fundamental laws is an important issue when deciding between the three broad ontological options of fundamentalism (of which the thesis that physics is complete is typically a sub-type), emergentism, and disorder or promiscuous realism. Cartwright’s assault on fundamental laws which argues that such laws do not, and cannot, typically state the facts, and hence cannot be used to support belief in a fundamental ontological order, is discussed in this context. A case is made in defence of a moderate form of fundamentalism, which leaves open the possibility of emergentism, but sets itself against the view that our best ontology is disordered. The argument, taking its cue from Bhaskar, relies on a consideration of the epistemic status of experiments, and the question of the possible generality of knowledge gained in unusual or controlled environments.

Introduction

My treatment of the status of fundamental laws in this paper grows out of an ongoing interest in the problem of the completeness of physics. The thesis that physics is complete, which I will refer to as the ‘completeness thesis’ is a more modest doctrine than any particular version of physicalism, and can be glossed as the thesis that the domain of the physical is causally closed. A well known, and more precise, statement of what this completeness involves is given by Papineau (1993: 16): I take it that physics, unlike the other special sciences, is complete, in the sense that all physical events are determined, or have their chances determined, by prior physical events according to physical laws. In other words we need never look beyond the realm of the physical in order to identify a set of antecedents which fixes the chances of every physical occurrence. A purely physical specification, plus physical laws, will always suffice to tell us what is physically going to happen, insofar as that can be foretold at all. The claim of completeness is rarely made on behalf of any science or domain. Meteorology, for example, concerns phenomena which may have antecedents in vulcanology or economics, and any reasonable account of the antecedents of, say, global warming could be expected to refer, as well as to factors within the scope of meteorology, to chemistry, the history of technology, economics, geology and so on. It would clearly be ridiculous to assert the completeness of meteorology. It is worth noting, though, that completeness claims have been made from time to time on behalf of various sciences. Durkheim’s dictum that the explanation of any sociological fact is another sociological fact (1964: 95, 110) is, at least on the face of it, an example of this, and Leibniz’s metaphysics of preëstablished harmony can be seen as simultaneously making the claim on behalf of both the physical and the mental. (This clearly contrasts his position with the standard reading of Descartes’ dualism, where neither the mental nor the physical would be complete at least as long as there was one thinking thing united with a body.) In addition Papineau (1990) has explained how it might be possible to develop a completeness principle within some versions of phenomenalism. Most usually though, in contemporary discussion, the claim is made with respect to physics.

Although I will be discussing the status of fundamental laws it is worth pointing out that for present purposes I am not especially interested in many important questions concerning the nature and features of laws. It will not be my concern whether laws are ideally deterministic or probabilistic, or, if probabilistic, how such probabilities are to be interpreted. Whether laws relate events, or should be seen as ascribing capabilities of some kind to individuals or entities will, on the whole, similarly be left aside. The problem which is on centre stage here is that of the possible closure of the physical, and this question cuts across all of these issues. The way in which the completeness issue is more limited in scope than that of physicalism is simple: if physics was complete then that fact alone would not decide how things were with everything else. So there might be nothing else,[2] or whatever else there was might be epiphenomenal, or relate to the physical along the lines of one of the many theories of identity or supervenience presently on offer, and so on. Irrespective of that, though, any version of physicalism has to be committed to the completeness of physics, since without that premiss mental events would not be ‘anomalous’ (Davidson 1970), mental states would not be ‘nomological danglers’ (Feigl 1958), and there would consequently be no arguments for the identity of the mental and physical via the rejection of overdetermination (e.g. Papineau 1993). So my objective here is to consider one aspect of the debate over the completeness thesis, rather than discuss physicalism in general.

The particular line of thinking I wish to consider here, centred on Cartwright’s analysis of fundamental laws, is one which, if defensible, would have the effect of seriously undermining or even destroying the acceptability of fundamentalism and hence of forms of the completeness thesis tied to fundamentalism about laws. I propose to give reasons for rejecting that line of thinking. But my arguments will be short of decisive. Not only that, since they do not rule out emergentism, by themselves they do not amount to a defence of the completeness of physics although they make a contribution to that project.

A Selection of Worlds

What is at issue here can be made clear by considering three competing images of the world in which we find ourselves. The images in question are those of the fundamentalist, the emergentist, and what, following Dupré (1993: 18), we can call the promiscuous realist. The fundamentalist — the use of the term in this context is due to Cartwright (1994) — holds that there is some finite set of laws (however conceived) which can account for all phenomena, everywhere. A simple illustration of the spirit of fundamentalism can be seen in the wording, especially the first two words, of Newton’s first law of motion, the principle of inertia, which reads, in English, ‘Every body continues in its state of rest, or of uniform motion in a right line, unless it is compelled to change that state by forces impressed upon it’ (1934: 13). That’s the kind of law fundamentalists like: ones which, supposedly, apply to every entity, event or process of some kind, in Newton’s case to bodies with masses. (Note that I am not claiming that Newton actually was a fundamentalist, merely that his work includes examples of laws of the fundamental type.) A natural way to understand the view that physics is complete is to read it as a claim about physical laws. Note the prominent place of laws in Papineau’s formulation quoted at the beginning of this paper. In this case the thesis that physics is complete can be seen as a species of fundamentalism which holds either that there is some subset of the fundamental laws which account for all physical effects by reference to only physical factors, or, more simply, that all fundamental laws are physical. This is not the only way to understand the completeness of physics, but it is the way most relevant to the argument of this paper, so in what follows when I refer to fundamentalism I will have in mind a kind of fundamentalism which also involves commitment to the completeness of physics. Where there is a danger of ambiguity I will refer to ‘physical fundamentalism’. It is worth noting, though, that physical fundamentalism makes a stronger claim than the completeness thesis, since physics could be regarded as complete without any endorsement of fundamentalism being required for the simple reason that the completeness thesis does not entail any particular commitments about laws. It is a clear consequence of this that damage to fundamentalism need not necessarily harm the completeness thesis.

Cartwright describes the world of the fundamentalist as one where all the facts ‘belong to one grand scheme’ and hence where facts ‘legitimately regimented into theoretical schemes’ have a special status, but contends that this doctrine is one ‘we must resist’ and later offers an image of a patchwork world consisting of ‘tens of thousands of patches, cut up in no particularly logical way, exhibiting tens of thousands of different regularities of countless different forms’ (1994: 281, 298). On this view there just is no set of fundamental laws of the ‘every body’ type — merely local and perhaps transitory regions of particular kinds of order. In the essay just quoted Cartwright uses the image of a patchwork of laws, a view she calls ‘nomological pluralism’ (1994: 288). The corresponding ontology is also pluralist, the world described by a patchwork of laws is itself a patchwork. Here Cartwright is following the principle that we ‘best see what nature is like when we look at our knowledge of it’ (1983: 13). Her position is in important ways similar to that of Dupré who, in The Disorder of Things, argues for the need to recognise the ‘underlying ontological complexity of the world’ (1993: 7) and, as noted, dubs his preferred view ‘promiscuous realism’. I will adopt Dupré’s term and oppose promiscuous realism to fundamentalism in what follows.

What has been said here does not exhaust the options, though. An intermittently popular position on these questions is emergentism, which (in some versions of that doctrine) sees a hierarchy of kinds of law, typically starting with physical laws as a foundation and including, for example, biological laws for those material entities which are alive, psychological laws for those living beings which are conscious, socio-economic laws for those conscious beings which associate in certain ways, and so-on. There are many examples of emergentist theories but for my purposes here I only need to note that at least some emergentists fall, in a sense, between physical fundamentalism and promiscuous realism. The type of emergentist I am thinking of would hold that physical laws are indeed generally applicable in some sense, but they fail completely to fix the likelihood even of certain physical outcomes which are rather co-determined by both physical and non-physical laws. Bhaskar, for example, holds that some basic physical laws such as that of the conservation of mass-energy can be held to be true, but argues that such laws do not by themselves decide what will happen, only place restrictions on what can happen (1977: 109).

The in between quality of emergentism can be see from the ways in which it might appear offensive to either physical fundamentalists or promiscuous realists. From the perspective of the committed physical fundamentalist, emergentism seems like an unacceptable compromise position, raising too many difficult questions about the status of the ‘emergent’ laws, the empirical content of the claim that there even are such laws, and the proper account of the conditions under which they might be expected to arise. From the point of view of the fundamentalist who thinks that physics is complete, emergent laws are unnecessary, and also undesirable since they suggest the overdetermination of at least some physical effects.

On the other hand a serious promiscuous realist is likely to regard emergentism as similarly obnoxious for conceding too much to the fundamentalist, and creating a position amounting to a kind of hierarchical fundamentalism. Cartwright, for example, protests against the emergentist that the view that macro-properties ‘come out of nowhere’ falls afoul of the fact that there is ‘nothing of the newly landed about these properties’ (1994: 290). She also makes clear that she wishes to go beyond the simple rejection of downwards reduction typical of emergentism, and assault the possibility of ‘cross-wise reduction’ (1994: 281) in a way which directly undermines the defensibility of the view that there even are nomological or ontological foundations of a sort congenial to either physical fundamentalism or emergentism. In partial defence of the emergentist here it is worth recalling that there is some justification for thinking that there have been living things longer than there have been conscious things, and also that there have been things longer than there have been living ones. On cosmological time scales all manner of properties are likely to be very newly landed indeed, some more so than others. And emergentists of the sort at issue here, just like promiscuous realists, would deny that physics is complete, and hence have common foes in physical fundamentalism and the completeness thesis.

The point of this brief survey, getting these three ontological options on the table, is to make clear what at least one of the issues hanging on the status of fundamental laws is. If such laws are philosophically respectable then we seem to have a choice between emergentism and physical fundamentalism, perhaps even in the extreme form of the completeness of physics. If, though, fundamental laws lack the required support then, to the extent that we are realists, we had better be promiscuous.

In much of the literature, especially around the middle of the twentieth century, what we are here calling fundamentalism was associated with an expectation which can be glossed as ‘order at the top: order at the bottom’. What I mean by this is that fundamentalists tended to think that order, whether taxonomic or in the form of regularities, at just about any scale in the world would stand in some kind of relatively stable, and itself law-like, relationship with the basic ontological order imagined to entail the truth of some set of fundamental laws. There are many examples of this tendency, including theories of type-type identity, causal theories of natural kinds, programmes for inter-theoretic reduction based on bridge laws and the like (e.g. Oppenheim and Putnam 1958, Putnam 1975, Kripke 1972).

This association is not, as we will see, a necessary one, but it has the effect of presenting two likely targets to the anti-fundamentalist. One approach would be to make a direct attack on the view that there is order at the bottom at all, or that there even is a coherent sense to the required notion of a ‘bottom’. Another would be to defend the view that ‘disorder at the top’ or failures of law-like relations between top and bottom, weakens any inference to order at the bottom. This second option would only help against forms of fundamentalism which hold that the truth of some set of fundamental laws entails that there be related forms of order at non-fundamental levels, though. In what follows I want briefly to explain why neither disorder at the top nor failures of tidy top-bottom relations can be decisive considerations here, and then move on to consider how Cartwright’s treatment of fundamental laws damages the fundamentalist position.

Fundamentalism with Disorder

One example of an attempt to argue from disorder at the top to disorder at the bottom can be found in the work of Dupré. In The Disorder of Things: Metaphysical Foundations of the Disunity of Science Dupré argues for a promiscuous realist position committed to recognising the ‘ontological complexity of the world’ (1993: 7). A significant part of his argument is targeted at the Kripke-Putnam theory of natural kinds (Putnam 1975, Kripke 1972) which sees natural kinds as strictly related to some definite microphysical structure or other theoretical truth which fixes the extension of the kind in question. Dupré’s major target is clearly the ‘order at the top: order at the bottom’ way of seeing things, rather than minimal order at the bottom fundamentalism.

Dupré mounts an energetic attack on the notion that there are or could be such relations, calling the Kripke-Putnam theory ‘entirely untenable’ because no possible set of experts could be expected to fix the extensions of perfectly good natural kind terms in the ways needed, and because it would be unacceptable arbitrarily to allow one theoretical orientation to trump others, not to mention allow it to trump well established and less formal ways of picking out kinds. With particular reference to biology Dupré contends that the Kripke-Putnam approach ‘founders on the complete absence of the sameness relations its application would require’ (1993: 24-25).

Dupré’s preliminary conclusion is that his survey of kinds in biology supports promiscuous realism, since nothing he has said about ‘either about scientific kinds, or about the kinds of ordinary language, suggests that these kinds are in any sense illusory or unreal’ (1993: 36). Anticipating fundamentalist resistance committed to some in principle attainable fit between order at the top and order at the bottom within scientific discourse, he extends his argument to the consideration of specifically theoretical kinds such as ‘species’ (and later to the notions of ‘gene’ and ‘sex’), arguing that biologists favouring genetic, cladistic, morphological or ecological approaches can and do disagree about the classification of creatures into species, and concludes that ‘there is no metaphysical guarantee that whatever accounts for the coherence of species and their distinction (such as it is) from other species will be the same for all living things […] Thus both ontological and pragmatic grounds support a pluralistic approach to the species question’ (1993: 51).[3]

Dupré goes further than this, arguing that if we take the pluralism he defends seriously we need to recognise causal relations between the kinds we can pick out, and that this makes ‘causal completeness at the micro level impossible’ (1993: 101). His case here is, again, made substantially through an attack on various reductionist programmes and culminates in a criticism of Davidsonian anomalous monism (1993: 159-67). Neither fundamentalism nor the completeness thesis can be expected to stand or fall with the fate of anomalous monism, though, since that is too specific a target, and the most interesting and sophisticated parts of Dupré’s argument are those concerning reductionism. They form a clear example of an argument from disorder at the top to disorder at the bottom.

An anti-fundamentalist need not attack the view that there is order at the top, though, since disorder there (assuming there to be some) could in principle be explained in various ways, including fundamentalist ones. More specifically, there are at least two types of reason why the possibility of disorder at the top, and the possibility of there being no stable or neat top-bottom relationships, cannot be decisive here, and need not in any way bother the committed fundamentalist.

The first type of reason relates to the fact that over the past few decades many of those who defend the view that there is some kind of true fundamental, and usually physical, description of the world have abandoned the hope of finding bridge laws, type-type relations and other expressions of the ‘order at the top: order at the bottom’ ideal. Examples of this include Fodor’s account of the special sciences (1974), Davidson’s (1970) account of the mental as ‘anomalous’, Hellman and Thompson’s assertion that ‘the truth of physicalism is compatible with the utter absence of lawlike or even accidental generalized biconditionals connecting any number of predicates of the higher-level sciences with those of physics’ (1975: 564), and Papineau’s statement to the effect that it is in general implausible that type-type relations would hold between truths of a complete physics and other truths (1992: 12). Given all this, it is far from clear today, rather than twenty five years ago, what position is really the target of an attack on the expectation of order at the top, since by and large fundamentalists and defenders of the completeness thesis alike are no longer wedded to the ‘order at the top: order at the bottom’ ideal.

The second type of reason, parallel with the first, is that there is a growing body of evidence that simple deterministic and local interactions between simple elements can produce just the same forms of disorder, unpredictability and taxonomic undecidability celebrated by promiscuous realists. One kind of example of this is the broad area of research into cellular automata, pioneered by Conway, Wolfram and others (Wolfram 1983, 1984). A portion of this work goes on under the heading of ‘emergent’ computing (Forrest 1991, Langton 1991) where, under some interpretation, information, structure and interactions are discernible at large scales or ‘high’ levels of the computing system, yet inaccessible (or in some cases prohibitively unwieldy) at the level of the basic constituents of the system.[4] The point here is that even though it might be possible, in some cases, for initiates to argue over whether some configuration of cells in Conway’s Life is a ‘spaceship’ or a ‘puffer train’, just as biologists can dispute whether a given creature is a member or one species or another, one thing which is not in doubt in the cellular automata case is that there is a fundamental description to which any other description will stand in at least at token-token relationship.

Now neither of these two reasons can possibly show that any form of fundamentalism is true. To conclude that would be ridiculous, since such a claim would require the establishing of far more systematic and specific connections between the models just discussed and real systems and processes in the world than we are presently close to. Whether such connections can be established in any particular case is an empirical, and open, question. Rather, the effect of this brief discussion has been, I hope, to show that no argument from disorder at the top can be relied upon to count against the general thesis that there is order at the bottom. Disordered phenomena at non-fundamental scales can be saved by fundamentalists and promiscuous realists alike, which means that the proper way to proceed is directly to consider the issue of order at the bottom, and specifically for present purposes the status of fundamental laws.

What Order? What Bottom?

The broad outlines of Cartwright’s attack on fundamentalism are relatively well known. Cartwright has noted fairly recently that while How the Laws of Physics Lie (1983) was ‘generally perceived to be an attack on realism’ she has come to think that she was then ‘deluded about the enemy’ and that it is ‘fundamentalism that we need to combat’ (1994: 279). In the necessarily compressed treatment of her views in what follows I will read Cartwright’s work in the spirit suggested by these remarks: as a connected and evolving critical engagement with what she now calls fundamentalism.

In her first book Cartwright advanced the prima facie sensational thesis that the laws of physics are lies. More specifically she adopted and modified an existing distinction between theoretical laws, which are usually very abstract and general in form, and phenomenological laws, which are typically adapted to fit specific and real situations in the laboratory or in engineering work. Conceding that theoretical laws can have considerable explanatory power, she nonetheless reverses the traditional epistemological ranking of the two types of laws, favouring the empirically more successful and accurate phenomenological ones instead, and noting that ‘paradoxically enough the cost of explanatory power is descriptive adequacy. Really powerful explanatory laws of the sort found in theoretical physics do not state the truth’ (1983: 3). Phenomenological laws may have limited explanatory power, and also stand in no neat relationship with theoretical laws, but they can, in some cases, state the facts. Theoretical laws, whatever their explanatory power, cannot state the facts, and should hence be seen as ‘lies’. Her arguments for this conclusion can be separated into three main strands:

(1) The manifest explanatory power of fundamental laws does not argue for their truth.

(2) In fact the way they are used in explanation argues for their falsehood. We explain by ceteris paribus laws, by composition of causes, and by approximations that improve on what the fundamental laws dictate. In all of these cases the fundamental laws patently do not get the facts right.

(3) The appearance of truth comes from a bad model of explanation, a model that ties laws directly to reality. As an alternative to the conventional picture I propose a simulacrum account of explanation. The route from theory to reality is from theory to model, and then from model to phenomenological law. The phenomenological laws are indeed true of the objects in reality–or might be; but the fundamental laws are true only of objects in the model (Cartwright 1983: 3-4).

The argument that the explanatory power of fundamental laws does not sustain any claim for their truth points out that, taken as descriptions, i.e. as accounts of the facts, fundamental laws are manifestly false in all or most situations. Given this it just does not help matters to appeal to the explanatory power of such laws: that power, according to Cartwright, is clearly independent of their possible truth, which must be separately evaluated in each case.

The second argument complements the first by analysing the rule played by fundamental laws in explanations, and pointing out that real explanations involve major modifications to fundamental laws, including ceteris paribus clauses and the use of various other additional features, all of which are needed for descriptive accuracy. Were fundamental laws descriptively powerful to start with, i.e. were they ‘true’, none of this would be necessary, and the fact that it is indeed necessary shows quite straightforwardly the descriptive poverty of fundamental laws.

The final strand of argument completes the case in an important way, since the first two arguments alone leave open the possibility that the committed fundamentalist will just hold out for better fundamental laws in the future. Even if the explanatory of power of any given fundamental law does not argue for its truth, and if present fundamental laws can be shown to be false on the basis of the ways they have to be modified to play a role in explanations, it surely does not follow that no fundamental law could be true. That conclusion would plainly be a non sequitur. The simulacrum account of explanation meets this possible counter by arguing that the descriptive weakness of fundamental laws is something that they more or less have to possess in order to do the kind of explanatory work they do.

The argument for this conclusion begins (Cartwright 1983: 143-4) with a nod at Kuhn, who argued that certain general features of scientific practice could serve the function of keeping what would otherwise be rather disconnected and isolated enquiries in some kind of cohesion. Cartwright suggests that this might make sense of why fundamental laws tend to be few in number and also, in her sense, false. Thus the simulacrum account of explanation has it that fundamental laws play very much this role – providing a standard and partly unifying vocabulary enabling scientists to impose a kind of coherence on their heterogeneous rabble of phenomenological models. Although she sees fundamental laws as giving this kind of coherence, Cartwright is careful to make clear that she is generally opposed to any attempt to regard such laws as true, saying that ‘it usually does not make sense to talk of the fundamental laws of nature playing out their consequences in reality’ (1983: 160).

It is worth noting that the conclusion of the simulacrum account is also a non sequitur. It is one thing to shift the burden of argument onto the fundamentalist, and demand a defence of fundamental laws, but another entirely to require that accurate laws actually be produced in order to justify the belief that such laws could even possibly be true. I return to this shortly. For the time being, though, I need to note briefly some of the ways in which Cartwright is a realist. In How the Laws of Physics Lie she gives reasons for realism about both causes (1983: 74-86) and theoretical entities (1983: 91-93) subject to such causes and entities playing certain roles in explanation, and also to our not imagining that we are thereby committed to realism about the descriptions of those causes and entities in theoretical, or fundamental, laws. We can know that there is a kind of thing which can cause in certain ways without any fundamental law being true of either the thing or the cause. In Nature’s Capacities and Their Measurement (1989) Cartwright develops this view into a realism about capacities,[5] or the tendencies of things to cause in certain ways, and to respond to certain causes. I do not want to rehearse or criticise her arguments for these realisms, but do need to note her commitments, and also to emphasise that for Cartwright these are distinct from fundamentalism and furthermore can be endorsed in conjunction with anti-fundamentalism.

A short look at an example, discussed by Cartwright (1994), will make more clear what is at stake here. Having earlier used the case of being able to drop a pound coin from an upstairs window with some accuracy as an example of a kind of reliable knowledge, Cartwright considers a case, which she acknowledges as being due to Neurath, where what is dropped is a $1000 bill, and where it is dropped on a windy day. She states that mechanics ‘provides no model for this situation’ (1994: 283) but also that it is characteristic of the fundamentalist that she or he think that there is ‘in principle [...] a model in mechanics for the action of the wind [on the banknote], albeit probably a very complicated one that we may never succeed in constructing’, and further that this belief is ‘essential for the fundamentalist’ (1994: 284).

Against this faith Cartwright asserts that if ‘there is no model for the 1000 dollar bill in mechanics, then what happens to the note is not determined by its laws’ (1994: 284). The question arises, then, of whence the fundamentalist might draw his or her characteristic faith. Cartwright insists that:

The successes of mechanics in situations that it can model accurately do not support it, no matter how precise or surprising they are. They show only that the theory is true in its domain, not that its domain is universal. The alternative to fundamentalism that I want to propose supposes just that: mechanics is true, literally true we may grant, for all those motions whose causes can be adequately represented by the familiar models that get assigned in force functions in mechanics. For those motions mechanics is a powerful and precise tool for prediction. But for other motions, it is a tool of limited serviceability (1994: 284). If this line of argument goes through then the fundamentalist and emergentist alike are left in a very poor state indeed. But how should we go about evaluating this argument? Cartwright’s case is elegant, careful and detailed, far more so than the sketch just offered shows. It will certainly not do simply and dogmatically to hold out for better fundamental laws, or baldly to assert faith in their possibility. And Cartwright is surely correct to say that we ‘best see what nature is like when we look at our knowledge of it’ (1983: 13). But then the question becomes different: what is the best way to decide what the state of our knowledge tells us about what nature is like? In response to this question I think it is possible to outline a defence of what I will call moderate fundamentalism, which disagrees with Cartwright on some key points.

Moderate Fundamentalism

One important way in which the completeness question is independent of that of fundamental laws is this: to defend the closure of the physical we really only need good reason to think that physical outcomes have only physical antecedents. In Cartwright’s language we could say that what is needed is the notion of physical outcomes, or changes involving physical entities, having their likelihoods affected by only physical capacities. If, after all, we are agreed that capacities are real, then the question which capacities are generally relevant to physical outcomes is an empirical one, and the likelihood of the completeness of physics might seem like a viable topic for debate. But even to start to contest this possibility we need some reason to think that our knowledge of physical capacities can be general in its applicability, and this notion too is threatened by Cartwright’s arguments. We have seen what she says about the $1000 bill in the wind. Not only that, she notes that Hacking is well known for his remark ‘If you can spray them they exist’ (Cartwright 1994: 291) but opts herself for the option ‘When you can spray them, they exist’ saying that in doing so she is being ‘more cautious’ (1994: 292).

It has been noted already that the inference from the patchwork state of knowledge to a patchwork ontology, or to the general unacceptability of fundamental laws, is a non sequitur. But that cuts both ways, since the same point could be made against any given exhibit brandished by the persistent fundamentalist. It seems beyond argument that our present state of knowledge is on the whole more like Cartwright suggests than the standard fundamentalist would want it to be. But it is reasonable to ask whether it is really fair for Cartwright to say, as she does, towards the end of her discussion of the unpredictable wind-tossed $1000 bill:

Many will continue to feel that the wind and other exogenous factors must produce a force. The wind after all is composed of millions of little particles which must exert all the usual forces on the bill, both at a distance and via collisions. That view begs the question (1994: 285). I want to argue that it is not, and will begin by noting another statement made by Cartwright, where she concedes that there are indeed rare cases where fundamental laws can be descriptively accurate. Such a situation, she says, ‘may occur by accident, or, more likely, we may be able to construct one in a very carefully controlled experiment, but nature is not generally obliging enough to supply them freely’ (1983: 161).

So there are rare and special situations in which fundamental laws are not lies. Cartwright would say that these situations mean little or nothing about the status of fundamental laws in other contexts, the fundamentalist would not. What, then, is the relationship between these exceptional circumstances and the buzzing confusion of the world in general? Cartwright’s answer is that since belief in the veracity of laws can be justified only by descriptive accuracy, there is no significant reason to think that any law holds outside its domain of applicability. The fundamentalists answer, in contrast, will be that experimental situations are somehow indicative of general features of the world, and the fundamentalist will need some reason for thinking that knowledge of these features is somehow applicable beyond the special conditions under which fundamental laws are capable of stating the facts.

In A Realist Theory of Science (1977) Bhaskar identified and engaged with many of the same basic problems as Cartwright does in her work, and came to conclusions both similar in some respects and strikingly different in others. I want briefly to describe the core of his argument, and oppose some of its conclusions to those of promiscuous realism and nomological pluralism, or order to argue myself for the possibility of generally valid scientific knowledge in a way which is not, as Cartwright suggests, question begging. Bhaskar’s focus in his defence of what he calls transcendental realism is, to a significant degree, the scientific experiment, precisely the context in which Cartwright allows that theoretical or fundamental laws may, sometimes, state the facts. Bhaskar distinguishes between open and closed systems, where closed systems alone manifest consistent and law-like relations between events,[6] and observes that ‘an experiment is necessary precisely to the extent that the pattern of events forthcoming under experimental conditions would not be forthcoming without it’ (1977: 33). This seems difficult to argue with, and it also makes sense to think of many experiments as procedures for bringing about closure in Bhaskar’s sense. He then and argues that if ‘experimental activity is to be rendered intelligible’ then we must allow that ‘natural mechanisms endure and act outside the conditions that enable us to identify them [in order] that the applicability of known laws in open systems, i.e. in systems where no constant conjunctions of events prevail, can be sustained’ (1977: 13).

What Bhaskar means by a natural mechanism, or as he more often puts it a generative mechanism, is some real and causally active feature of the world. Such generative mechanisms need not generally produce consistent outcomes, though, since they may be present in various combinations and conditions. So for Bhaskar it is not generally the case that the typical activity of a generative mechanism stands in any stable relationship with the manifest flow of events, a point he marks by saying that the events are often ‘out of phase’ (1977: 13) with the mechanisms. When they are in phase (for whatever reason) we can say that the relevant system is closed. Bhaskar opts to call our knowledge of these generative mechanisms ‘laws’, but argues that laws as he sees them are generally explanatory tools, and only contingently descriptive or predictive. But then an important consequence for an influential traditional conception of laws, which sees laws as relating events, comes into the foreground. In open systems stable relations between events do not generally obtain, but ‘clearly if the law-like statements whose antecedents are instantiated in open systems are interpreted as invariant empirical regularities they must be regarded as false’ (1977: 132).

This is pretty much the point at which Cartwright would say that such laws are, in general, false, but also that no important consequences for their general applicability follow from the fact of their being true in the unusual conditions of an experiment. Bhaskar prefers to see the situation as a dilemma for anyone wedded to the notion that laws relate events:

...for to the extent that the antecedents of law-like statements are instantiated in open systems, he must sacrifice either the universal character or the empirical status of laws. If, on the other hand, he attempts to avoid this dilemma by restricting the application of laws to closed systems (e.g. by making the satisfaction of a ceteris paribus clause a condition of their applicability), he is faced with the embarrassing question of what governs phenomena in open systems (1977: 65). Bhaskar, though, opts to sustain what he calls the ‘universal character’ of laws, i.e. their general applicability, by conceding that they are not primarily empirical. This position is in some respects similar to Cartwright’s if we set aside the specific issue of which items of our knowledge we should call ‘laws’, since Bhaskar’s contentions are that we should be realists about the tendencies, or ways of acting, of things (1977: 46) just as we should be realists about the things to which we attribute causal powers, while Cartwright defends realism about capacities and entities. Although there are differences of vocabulary and detail here, the agreement is striking. What separates the two philosophers on this point is rather the issue of the generality of our knowledge. Bhaskar’s argument for generality is Kantian in form: ‘experimental activity can only be given a satisfactory rationale if the causal law it enables us to identify is held to prevail outside the contexts under which the sequence of events is generated’ (1977: 33).

Cartwright herself puts a Kantian gloss on her argument for the patchwork of laws, where the activities of planning, predicting, manipulating and so on would be impossible without the objectivity of local knowledge: ‘Unless our plans about the expected consequences of our actions are reliable, our plans are for nought. Hence knowledge is possible’ (1994: 277). But, as we have seen, she is also careful to point out that for her part the appropriate ontological caution requires that we restrict our confidence in the applicability of our knowledge to cases where that knowledge can deliver accurate descriptions, i.e. that we say only ‘when we can spray them, they exist’.

Neither Cartwright’s position nor Bhaskar’s refutes the other. Both lay claim to the same evidence, but disagree over its interpretation, or over the appropriate metaphysical commitments which do best justice to the evidence. We do not generally, at least any more, expect metaphysics to tell us what the world must be like in the same ways that Descartes, for example, argued that the most basic laws of nature, including the principle of inertia, could be deduced from reflection on the nature of God, who qua perfect being would always act consistently (1991: 57-61). Rather the job we typically demand from metaphysics these days is that it make some kind of sense of our opinions about, and knowledge of, the world, and that it do no major violence to common sense.

We have a choice here between saying, with Cartwright, that when in experimental situation(s) X we have reason to suppose a capacity or entity Y to be real, we should conclude that Y is indeed real, but only in X situations, or saying, with Bhaskar, that in such a case we could properly conclude that Y is generally real, but only manifest in X situations. A Bhaskarian, or what I am here calling a moderate fundamentalist, would say that the fact that we can make a variety of different capacities manifest in this way makes sense of the fact that systems in general are not closed: if mechanisms did not interfere, compete and reinforce in a variety of ways experiments would not be necessary, and we could read the laws of nature directly off the normal course of events.

So to say that what we do in experiments is enable preëxisting and enduring tendencies to become manifest because of the simplicity or restrictedness of the experimental situation, then there is nothing unreasonable or dogmatic about taking those tendencies to be generally active, even when the flow of events is out of phase with them. To conclude this is, in general, no less reasonable than to suppose that the light in my refrigerator retains the capacity to come on when the door is opened, during intervals when the door is in fact closed.

Not only that, we can see why Bhaskar describes the problem of explaining what happens in open systems as ‘embarrassing’ for one who thinks that laws hold only where descriptively accurate, and how it might also be awkward for one holding the simulacrum account of explanation. A moderate fundamentalist confronted with an uncrumpled $1000 bill blowing in the wind can say that we know from experiments in a vacuum that falling bodies accelerate at the same rates, from other experiments with fluids and gasses that the air can exert a force, from other still that air is composed of molecules which can be turbulent, and so on. It is fair to say that given such knowledge we can predict that the path of the note will be practically impossible to plot in advance, and explain why this is so. And our explanation will not be a high-level simulacrum which organises otherwise disunified local knowledge, but rather a true statement of the actions of real tendencies in the world which produce the forces acting on the note. There is nothing incautious about this, and no questions are being begged.[7]

Conclusions

I do not want to claim that Cartwright’s position has been shown to be seriously misguided here. Rather My conclusion is that reasoning along the lines suggested by Bhaskar shows the way to reasonable confidence in the generality of our experimentally gained knowledge, and hence provides a serious alternative to promiscuous realism. The point made earlier which I wish to return to now is that this moderate fundamentalism is enough to get the completeness thesis off the ground. The reason for this is that if we can indeed reasonably take some of our knowledge to be general, we can meaningfully ask whether only physical capacities (associated with mass, charge and the like) are relevant to physical outcomes, or whether non physical ones (for example wealth or war) sometimes play a role. We can also set about trying to establish what kinds of evidence might count either way.

Bhaskar himself, as an emergentist, would say that physics is not complete, that the generality of its laws is consistent with physical capacities being only co-determinants or constraints with respect to some outcomes. Myself, and others, would say that physics is complete. My point here is not to argue that physics is complete, though, merely to show that there is a case to be made that the question is significant, empirical, and that the nature of our knowledge is such that we can attempt to answer it.

It will help briefly to sum up. Nomological pluralism denies general knowledge of basic features of the world except where justified by descriptive success, and rejects fundamentalists who take their knowledge to extend beyond contexts where it is empirically successful. Promiscuous realism denies the ontological order fundamentalists take to prevail at some possible level of description. Both nomological pluralists and promiscuous realists reject the completeness thesis as well. The claim that physics is complete is more limited one than full blown fundamentalism, though, and the moderate fundamentalism needed to formulate and attempt to defend the completeness thesis appears on examination actually to be more cautious than the ontological pluralism to which Cartwright inclines.

Quine wrote of ‘limning the true and ultimate structure of reality’ (1960: 221). This image gives me a simple way of stating my conclusion: we may succeed or fail in the labour of limning, the result may or may not be one congenial to the ambitions of physicalists, but the outcome cannot be known in advance, and we are not making any serious mistakes if we set out to try.

Author

DAVID SPURRETT
Department of Philosophy
University of Natal
Durban
4041
South Africa
email: spurrett@nu.ac.za

Note on Contributor

David Spurrett is Lecturer in Philosophy at the University of Natal, Durban in South Africa, and Visiting Research Fellow in Philosophy at King’s College, London. Areas of active research include philosophy of science, the completeness of physics and seventeenth century natural philosophy.

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NOTES

1
This paper was presented under the title ‘Fundamental Laws’ at the 25th annual philosophy of science conference held at the Inter University Centre in Dubrovnik, Croatia, 12-17 April 1999. I am grateful to those present for their comments and criticism, especially James Robert Brown, Richard Arthur, David Davies, Andrew Reynolds and Jean-Pierre Marquise. I would also like to acknowledge the benefit of discussions of an earlier version of the paper with David Papineau and Keith Hossack at King’s College, London. [back]
2
On this point I am disagreeing with Blackburn (1993: 233) and anyone else who holds that the physics should also fix the supervenience relations as well. Although this point is not critical for my argument here, I do not regard it as a possible physical question what relation obtains between the physical and anything else, including the mental. [back]
3
Davies (1996) reads Dupré as developing a line of argument compatible with Fodor’s (1974) account of the special sciences. I think that a large part of what Dupré says can be interpreted in that way, but take his intention to be the defence of a more radical position, denying even the kind of fundamental description functionalists acknowledge to be possible, but maintain to be of little or no value for the work of the special sciences. Dupré’s subtitle is, after all ‘Metaphysical Foundations of the Disunity of Science’. [back]
4
This point is made explicitly in Cilliers (1998) and also critically discussed in Spurrett (forthcoming). [back]
5
See Cartwright (1989: 1) for an explicit statement of realism about capacities. Cartwright explains at the same point that the general argument of Nature’s Capacities and Their Measurement is not formulated in terms of capacity realism since she wished to avoid debates over realism not central to her purposes. [back]
6
Bhaskar’s specific critical target is positivism, so his typical closed system, by and large, is one in which a relationship constant conjunction obtains between events. It does no significant violence to the structure of his arguments to deploy them more generally in the way I am here. [back]
7
It might be objected at this point that much of this sounds reminiscent of things Cartwright herself says. Quite so – after all she allows that forces can be regarded as a kind of ‘trying’ even where their effects are not manifest (1994: 285-286). But what is at issue here are her claims to the effect that ‘when we can  spray them, they exist’ is more cautious a conclusion that the ‘if’ formulation, and that the view that the wind exerts a force on the banknote at any instant ‘begs the question.’ [back]