Sun Nov 5, 2006

More Cartwright

Following on from Omar’s post about Nancy Cartwright’s The Dappled World, I will abuse my right to post here to point to this review of the book by Laurie Paul. Paul is a very intelligent philosopher (her unwise decision to marry me was an uncharacteristic lapse), and her review gives a good sense of the response to Cartwright’s position within philosophy. I’ve found that social scientists who read Cartwright’s book are excited and interested by it. One reason for this is that her approach resonates nicely with how many researchers (and especially social scientists) feel like they do their work. This is not accidental—unlike many philosophers of science, Cartwright pays attention to the social sciences as well as the natural sciences, and has a much better feel than many philosophers of science for how work in various fields really gets done.

At the same time, philosophical readers tend to worry about the lack of detail at key points, or question what her strongest general claims really entail when you look at the details. Social scientists reading work like this tend not to go through it with such a fine-tooth comb because, frankly, we are not used to reading work all that carefully. Getting the gist of a finding or program is usually enough to be going on with. This is fine for keeping up with the literature in our own fields (where the theory is relatively simple), we may be tempted to approach the philosophy of science as we might approach lunch at a Dim Sum place: I’d like a little spicy anti-realism with a good serving of empirical regularity and a side-order of legitimation for my field, and will subscribe to any view which appears to deliver this to my table. The nitty-gritty of what’s going on in the kitchen is of less concern. As Paul comments,

In any case, it should be clear that there are some robust metaphysical assumptions here about objects, properties and powers that I think Cartwright should flesh out. The view has many virtues, but until the details are worked out it is hard to assess the overall attractiveness of the thesis. Metaphysicians interested in a realist account of laws will have many questions about this ontology, especially about the nature of the capacities or causal powers that are being relied on so heavily.

As social scientists, we might think of Cartwright’s ideas about nomological machines as providing an accurate philosophical portrait of the actual practice of model building and experimentation in the social sciences, as well as revealing its strong limitations. Perhaps all we do is, at best, construct such machines, heavily shielded from outside disturbances, in an effort to identify regularities which we then call general laws as if they were observable in ordinary situations. Or, much more often, we can’t even do this and our statistical methods are not representing any real process at all. But this is only part of her project: Cartwright is also making stronger claims about the world as such. She argues that there are parts of the world where laws do not apply, for instance, and on any realist understanding of what a law of nature is this is a difficult claim to make sense of. She emphasizes the (humanly) constructed nature of the repeatable situations that make for nomological machines, which gives the anti-realist element to her thinking. Paul construes this as follows:

[For Cartwright] … in cases where there is no natural repetition, what makes something a nomological machine, hence a situation where a law applies, is whether it is controlled by us, whether it operates in an environment shielded by us (73). … This gives us a human element in the natural and social sciences, an element reflected in what we designate as laws. But it is not entirely incompatible with realism, for laws in this sense aren’t all that we have: we also have capacities or natures, and these are robustly ontological, i.e., they exist independently of anything pragmatic. Moreover, these natures are what give rise to what we characterize by our laws, and so the world has an independent character after all. Although situations to which laws apply can be constructed by us, not just anything goes, for what can be covered by a law is constrained by the natures of objects, and even if a law fails to apply in a situation, it doesn’t mean that the interactions of the objects are random or arbitrary. If the way I’ve interpreted her view is correct, then Cartwright is indeed occupying a middle ground between realism and (at least a weak version of) antirealism, which is where she explicitly places herself.

On this interpretation, the claim that there are “parts of the world where laws do not apply” is much easier to stomach because it rests on a distinctive conception of what a law is.

A final thought—one that foreshadows the upcoming discussion of MacKenzie’s book—is that Cartwright’s nomological machines may be related in interesting ways to the performative technologies of the finance studies people. It is tempting—though here I am succumbing to just the kind of metaphorical fancy that I earlier said bugs me—to think of the performativity literature as detailing the construction and distribution of nomological machines for markets. These are the reproducible techniques, in other words, that regularize and make more law-like the settings that they initially claim to describe once they are released into them. But the possibility of such a connection should make us more rather than less careful about specifying just what it is we mean in such cases.