Cartwright, Nancy (1944–)

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CARTWRIGHT, NANCY
(1944–)

Nancy Cartwright, as of 2005, held several academic positions, including professor of philosophy in the Department of Philosophy, Logic, and Scientific Method at the London School of Economics (since 1991); director of the LSE Centre for Philosophy of Natural and Social Science (since 1993); and professor of philosophy in the Department of Philosophy at the University of California at San Diego (since 1998). She had also served on the faculty at the University of Maryland (1971–1973) and Stanford University (1973–1991). She is the recipient of a MacArthur Fellowship and is a Fellow of the British Academy.

Cartwright first became widely known for the radical thesis, presented in her landmark 1983 collection of essays How the Laws of Physics Lie, that the fundamental laws of physics did not state truths about the world. The thesis is radical because philosophers have generally assumed that there is some set of underlying physical laws which, ultimately, describe all natural events. This is probably still a majority opinion among philosophers of science, though a much more controversial one than when Cartwright wrote these essays. At the same time she also proposed (along with Ian Hacking) a cautious realism about theoretical entities, which did not depend on people's ability to formulate true laws about them.

Cartwright's argument is based on a distinction between phenomenological and theoretical—or fundamental—laws. Phenomenological laws are, unsurprisingly, the laws that apply to actually observable phenomena. Their application is generally tightly circumscribed by detailed specification of the situations to which they apply. While fundamental laws may play an essential role in the formulation of phenomenological laws, the former are not themselves true. This is because they abstract from all the detailed ceteris paribus conditions that give phenomenological laws a chance, at least, of being true within their specific domains.

In her most recent book, The Dappled World (1999), Cartwright continues her attack on fundamentalism, the idea—from realism—that there is one unique set of laws applying to everything. The attack on fundamentalism, however, is now more uncompromising, as she has become increasingly skeptical about the usefulness of fundamental laws for deriving phenomenological laws. At the same time, a positive theme that she has developed throughout her career is increasingly emphasized: The conception of science not as searching for laws at all, but as constructing models. For models, the question of truth does not arise. They may more or less adequately represent parts of reality, and they may be more or less useful in providing understanding, explanation, and prediction.

Another theme more strongly emphasized in the later book is the disunity of science. Whereas a majority of philosophers of science accept a disunified science in the sense that laws in different domains are not reducible to laws of a more fundamental science, a majority of these philosophers see this as a consequence only of practical problems of complexity or the limited cognitive capacities of humans. Cartwright, on the other hand, is a leading advocate of a more radical position: that the autonomy of theories is indicative of what there is to know about the world. The world itself does not have a unitary underlying lawlike pattern. Its nomological structure is dappled.

The other related topic to which Cartwright has been among the most prominent contributors is the nature of causality. The decentering of fundamental laws from the vision of science naturally engenders skepticism about the Humean program of reducing causes to instances of laws. A project introduced in her first book—and developed in detail in her 1989 work, Nature's Capacities and their Measurement —is that an understanding of causality in terms of laws should be replaced with one in terms of capacities. In parallel with the emphasis on models, this move contributes to doubts as to whether laws are needed at all. The central thesis of this book is that science cannot be understood without assuming real capacities in the world. As is well known, Hume argued that positing capacities violated a proper empiricism. Cartwright, a committed empiricist, insists that capacities are as empirically accessible as laws and more specifically, that their measurement is a defining activity of science. In a further anti-Humean move, she argues that singular rather than generic causes are fundamental. A paradigm for Cartwright of causal knowledge is that aspirins have the capacity to cure headaches. Yet the canonical evidence for this claim is that on some specific occasions an aspirin actually does cure a headache.

This also connects to a central topic of her earliest work: probabilistic causality. This topic arises because capacities are to be thought of as being displayed only under specific circumstances, so that the relation between a capacity and its exercise is typically probabilistic. Conversely, Cartwright explores the question whether probabilistic relations can provide evidence for causes. Her answer is that they can, but only on the assumption that the effects are indications of real capacities in objects.

This entry has described some main themes from Cartwright's work in fairly abstract terms, but it should be emphasized that she has been a leader of the move to focus philosophy of science on detailed examination of exemplary cases of scientific work. For the earlier part of her career most of this work was addressed to physics. From the late 1980s she increasingly switched her attention to examples from economics, and is now a leading figure in the philosophy of economics. Perhaps surprisingly to those who see the sciences as hierarchically arranged with physics secure at the top of the heap, Cartwright finds many themes in common to physics and economics. A central idea linking the two is her interest in machines, which can also be seen as concrete instantiations of models. A paradigm from her earlier work is the laser. The moral of this example is that the laser concretely embodies the ceteris paribus clauses emphasized in her critical discussion of fundamental laws by a range of actual mechanisms that ensure the proper conditions for the exercising of the crucial capacity—in this case the capacity for inversion in a population of atoms. Central to Cartwright's work on economics is the idea of a socioeconomic machine. As an example, she considers the mechanism by which a central bank increases the money supply. Like the laser, this does not reflect a law of nature, but a capacity of a certain kind of money, under properly controlled conditions, to have an important economic effect.

Cartwright claims as a philosophical hero Otto Neurath, a founding member of the Vienna Circle. Her admiration is of his commitment to seeing in science the capacity to change the world. A concern with the social impact of science and philosophy of science, while often beneath the surface, has been discernible in much of Cartwright's work.

See also Laws, Scientific; Scientific Realism.