The question is raised, what is going on when there is a tendency for something to happen, but it does not happen. A conspicuous case is that in which there is an equilibrium between opposing forces. One answer, given, for example, by Anscombe and Geach, Harre, and Bhaskar, is that such tendencies are in a sense real, though not manifest. The other answer, given, for example, by Braithwaite and Mackie, is that statements of tendencies are conditional statements about what is (...) manifest but ones in which some antecedents are not specified. The first of these answers is criticized and the second defended. (shrink)

Ever since David Hume, empiricists have barred powers and capacities from nature. In this book Cartwright argues that capacities are essential in our scientific world, and, contrary to empiricist orthodoxy, that they can meet sufficiently strict demands for testability. Econometrics is one discipline where probabilities are used to measure causal capacities, and the technology of modern physics provides several examples of testing capacities (such as lasers). Cartwright concludes by applying the lessons of the book about capacities and probabilities to the (...) explanation of the role of causality in quantum mechanics. (shrink)

In this sequence of philosophical essays about natural science, the author argues that fundamental explanatory laws, the deepest and most admired successes of modern physics, do not in fact describe regularities that exist in nature. Cartwright draws from many real-life examples to propound a novel distinction: that theoretical entities, and the complex and localized laws that describe them, can be interpreted realistically, but the simple unifying laws of basic theory cannot.

The facticity view of fundamental laws of physics takes them to state facts about reality. To preserve the facticity of laws in the face of complex phenomena with multiple intervening factors, composition of causes, often by vector addition, is invoked. However, this addition should be read only as a metaphor, for only the resultant force is real. The truth and the explanatory power of laws can both be preserved by viewing laws as describing causal powers that objects possess, but this (...) view would require a new account of explanation. (shrink)