Theories of causal ordering: Reply to de Kleer and Brown

摘要

In their reply to our paper, “Causality in Device Behavior,” de Kleer and Brown seek to establish a clear product differentiation between the well-known concepts of causal ordering and comparative statics, on the one side, and their “mythical causality” and qualitative physics, on the other. Most of the differences they see, however, are invisible to our eyes. Contrary to their claim, the earlier notion of causality, quite as much as the later one, is qualitative and “derives from the relationship between the equations and their underlying components which comprise the modeled system.” The concepts of causal ordering and comparative statics offer the advantage of a formal foundation that makes clear exactly what is being postulated. Hence, they can contribute a great deal to the clarification of the causal approaches to system analysis that de Kleer and Brown are seeking to develop.In this brief response to their comments, we discuss the source of the structural equations in the causal ordering approach, and we challenge more generally the claim that there are inherent differences (e.g., in the case of feedback) between the “engineer's” and the “economist's” approach to the study of system behavior.