Procesos técnicos del sistema de abastecimiento

It is important to bear in mind just how far Cartwright is prepared to push her opposition to fundamental laws. The best way to make the point needed here is to take a short look at an example, discussed by Cartwright (1994). 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,15 where what is dropped is a $1000 bill, and where, for good measure, it is dropped on a windy day in St. Stephen’s Square. 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 emphasis added). The fundamentalist might rejoin at this point that the credentials of mechanics are well established in a range of other situations, and that this justifies any claim to their applying in the case of the banknote, but Cartwright urges as follows:

14 _{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.

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).

Here too, a fundamentalist rejoinder is likely. Surely, one feels tempted to insist, the note undergoes accelerations, a succession of rapidly varying ones to be true, but a real observable sequence of changes in velocity. And if this is so, then it is subject to forces, which are what cause accelerations. Cartwright has an answer to that line of thinking too:

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. When we have a good-fitting molecular model for the wind, and we have in our theory (either by composition from old principles or by the admission of new principles) systematic rules that assign force functions to the models, and the force functions assigned predict exactly the right motions, then we will have good scientific reason to maintain that the wind operates via a force (1994: 285 emphasis added).

Before long I turn to the question of what criticisms might be raised against this line of thinking, but for the time being need to emphasise that from Cartwright’s point of view any confidence in the general validity of some supposed law of nature outside the domains in which it can be justified by prediction is question begging. In case there is any doubt about how strictly she draws the line between cases where we do and do not have credentials for some kind of realism, her recent spin on Hacking’s experimental realism is worth bearing in mind:

Ian Hacking is famous for his remark, ‘If you can spray them, they exist.’ I have always agreed with that. But I would now be more cautious: ‘When you can spray them, they exist.’ (1994: 291-2)

If this remark is to count as drawing a distinction between her position and that of Hacking, the most likely interpretation of it is as saying that we are only justified in making claims about the reality of entities in cases where we are in suitable causal contact. Just as thinking that a law applies outside the conditions of its empirical adequacy is question begging, so too is confidence in the existence of things outside cases where suitable causal contact takes place.

If Cartwright’s 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, although further detail will be added in the

course of developing criticisms of it. 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 in some sense 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 a number of key points, and permits the Completeness Thesis to be sustained.

Before doing that I want to spend a little time making more clear what the implications of Cartwright’s position for the Completeness Thesis are.

4.

Consequences for the Completeness Thesis

In the sense already noted in connection with Dupré, one way of reading Cartwright’s position is as a general rejection of the notion of any causally complete model, theory or form of description.16 _{From this both} conclude that there is no ontological causal closure which we are justified in holding to obtain. Matters are not quite so straightforward, though, since unlike Dupré, Cartwright does not directly deny either any general thesis of causal completeness, or that specifically concerning the physical. It has been reported to me that in debate and conversation she is willing to defend the view that some material changes happen for, e.g., economic rather than any other causes,17 which would by implication deny the Completeness Thesis, but I have been unable to find any direct endorsement of such a position in her published work.

Despite this, there is a clear sense in which her work has significant implications for the Completeness Thesis, and no attempt to treat the credentials of that thesis within the broad scope of the philosophy of science can afford to ignore her challenge. I suggest that there are two central aspects to this challenge for my purposes:

In the first place a very natural way of thinking of the Completeness Thesis is as a claim about some set of laws, the physical laws, to the effect that they can account for the likelihood of all physical occurrences. If Cartwright is correct about the status of physical laws, then it would seem that any version of the Thesis framed in terms of laws would have to be false.

A further aspect of the point at stake here, is that in Cartwright (1989) and related material (1994, 1995a, 1995b) Cartwright makes no concessions to the view that some capacities might be more fundamental

16 _{Some opponents of physicalism have drawn on Cartwright’s criticisms of fundamental laws, for example} Wagner (1993: 133-135).

17

David Papineau (pers. comm. 1999). The case under discussion was the movement of some gold bars from one bank vault to another, and I understand Cartwright’s position on the matter to have been that economic forces (in some less-than-usually metaphorical sense of that term) are properly regarded as the real and irreducible cause of the physical motion of the gold.

than others, or that any could be genuinely fundamental at all. That electrons are the cause of the tracks in the bubble chamber, that aspirins are the cause of the relief of headaches, that economic factors are a cause of some social unrest, are all simply well-established claims about the existence and operation of some causal capacity. I have already noted her image of the patchwork of laws. What is important to realise is that not all of the patches are, on Cartwright’s view, to be regarded as physical.

In the second place the ways in which the Completeness Thesis is used in various debates18 _{relies on the} notion of the physical as being fundamental, that is as that which, no matter what else any material thing has, it has to have in virtue of being a material thing. Physicalist theses about the relationship between non-physical and physical properties typically rely on the idea that the physical properties are ontologically more basic. The notion that anything could be in this position is seriously threatened by Cartwright’s anti-fundamentalism, since she attacks the grounds which are typically used to justify the claim that physical things have this status. I should note here that in some ways her more recent work (1989, 1995a) grants far greater significance and generality to capacities, suggesting a line of defence for completeness. Further below I pursue just this line of thinking, for the time being I note only that even in recent defences of capacities Cartwright remains uncompromisingly opposed to fundamentalism (e.g. 1995a: 155).

The two aspects of Cartwright’s thought just noted come together, of course, in her rejection of fundamental laws. Before turning to the criticism of her views, a quotation from a recent paper will help fix the nature of her challenge in mind:

‘...some features of systems typically studied by physics may get into situations where their behaviour is not governed by the laws of physics at all. But that does not mean that they have no guide for their behaviour, or only low-level phenomenological laws. They could fall under a quite different set of highly abstract principles’ (1994: 189).