The Review of Metaphysics

Nancy Cartwright has held positions at Stanford University and the London School of Economics; she is currently professor of philosophy at Durham University and a distinguished professor at the University of California, San Diego. Primarily a philosopher of science, Cartwright has in recent years turned her attention to a field she dubs the “philosophy of social technology.” This field draws on the philosophies of natural, social, and decision sciences in order to increase the effectiveness of policy decisions by governments and other organizations. Nature, the Artful Modeler is comprised of seven essay-chapters, of which the first three are her Carus lectures (an invited, prestigious, biennial lecture series presented at a meeting of the American Philosophical Society) of 2017. The final four essays further develop and support the themes of the first three. These first three chapters are discussed below.

Cartwright’s first essay, “Natures’ Methods Are Our Methods,” concerns a theme that she has been developing over much of her career, beginning with How the Laws of Physics Lie. In brief, what many people consider to be the fundamental laws of physics—such as Newton’s law of gravity or Coulomb’s law of electrostatic force—apply directly to very few situations we consider, none of which occurs in our ordinary lives. What’s more, as Cartwright discusses in relation to the Millikan experiment (which measured the charge of the electron), the experimental apparatuses needed to discern the effects of even just those basic laws and particles are frequently extraordinarily elaborate; many simplifying assumptions are needed to relate data to theory. “Higher” laws of physics, such as Stoke’s formula for the calculation of the drag force on a sphere falling through a fluid, often admit of exceptions and must be modified ad hoc for changing conditions. Virtually all situations in our lives involve complexities that cannot be derived directly from physical laws; at best, a few can be modeled as confluences of disparate factors. So, Cartwright asks boldly, why should we assume that such situations are completely governed by fundamental laws? [End Page 401]

Her question is well put and congruent with other important ideas in physics. The uncertainty principle—that it is impossible to measure with complete accuracy both the position and the velocity of a particle—is said to imply that in reality the particle actually does not have a particular position or velocity. Why then think that all physical results are determined? And uncertainty certainly is not restricted to the subatomic level of nature. Chaos theory has revealed that future states of complex systems (such as, say, the weather) cannot be predicted beyond a certain point, even in principle. Even the future position of a single billiard ball rolling on a frictionless pool table is impossible to predict after a surprisingly small number of bounces off the cushions. So why think that “laws” fully specify an unpredictable outcome?

Instead of envisioning it as a deterministic taskmaster, Cartwright urges a view of Nature as an “Artful Modeler.” Just as we often attempt to navigate complex circumstances in our world by using assorted technical knowledge about divergent areas to forecast approximate outcomes (Cartwright uses a wonderfully convoluted example of the Nature Conservancy’s attempt to save the native Santa Cruz Island foxes from predation by golden eagles), so does nature itself. She writes, “Our scientific successes do not suggest that Nature operates by ‘law’ in fixing what happens; rather the world is full of possibilities and what happens is best recouped by artful modeling.”

Subsequent chapters defend and advance her ideas in detail. Chapter 2 asks: What is meant by a natural law? What are causal powers? Are possibilities real? What are we to think when multiple causes interact (such as vectors, electrical circuits, or the sounds of instruments in an orchestra)? The third chapter discusses her...