Clark Glymour

Twenty years ago, Nancy Cartwright wrote a perceptive essay in which she clearly distinguished causal relations from associations, introduced philosophers to Simpson’s paradox, articulated the difficulties for reductive probabilistic analyses of causation that flow from these observations, and connected causal relations with strategies of action (Cartwright 1979). Five years later, without appreciating her essay, I and my (then) students began to develop formal representations of causal and probabilistic relations, which, subsequently informed by the work of computer scientists and statisticians, led eventually to a practical theory of causal inference and prediction, a theory incorporating some of the sensibilities Cartwright had voiced (Glymour et al. 1987; Spirtes et al. 1993). That theory, and ideas related to it, have become a subfield of computer science with contributions far deeper than mine from many sources, and its inferential and predictive techniques have been successfully applied in biology, economics, educational research, geology and space physics. My timing was bad. Sometime in the interim, Cartwright abandoned her earlier views. It is only natural that when a philosopher abandons an opinion, she should criticize the views of those who retain or extend it, and perhaps for that reason in recent years Cartwright has made the work of my collaborators and myself the object of repeated lengthy (but invariably courteous) criticism, first in a chapter of her second book, (most of which, she wrote, was intended to explain the “philosophical reasons” why the ideas behind our initial methods could not work), then in several papers, and soon in a chapter of a forthcoming book. With the exception of a short comment on one of her examples in Nature’s Capacities and Their Measurement, I have written nothing in response. But a decade of criticism from a source so eminent eventually demands a considered reply. I will attend to the book just mentioned, and to a chapter of the manuscript of her new book, which contains the essential content of the intervening papers.