Abstract

Carl Gillett Department of Philosophy Northern Illinois University Suppose that scientists discover a high level property G that is prima facie multiply realized by two sets of lower level properties, F1, F2, …, Fn, and F*1, F*2, …, F*m. One response would be to take this situation at face value and conclude that G is in fact so multiply realized. A second response, however, would be to eliminate the property G and instead hypothesize subtypes of G, G1 and G2, and say that G1 is uniquely realized by F1, F2, …, Fn, and that G2 is uniquely realized by F*1, F*2, …, F*m. This second response would eliminate a multiply realized property in favor of two uniquely realized properties.[1] Clearly these are two logically possible responses to this type of situation, so when faced with it how do scientists respond in real cases? This is a matter of providing a descriptively adequate account of actual scientific practice. In support of the view that scientists opt for the “eliminate-and-split” strategy, one might propose that it is illustrated by the way scientists responded in the case of memory. Once upon a time, it was thought that there existed a single kind of memory. With the advance of science, however, it was discovered that it is possible to perform certain sorts of brain lesions that would lead to the selective loss of certain memory functions, while certain other sorts of brain lesions would lead to selective loss of certain other memory functions. These neurobiological dissociation experiments, one might say, support the view that, instead of a single overarching type of memory, there are distinct subtypes of memory, procedural memory and declarative memory. Thus, generalizing from this example, it might be suggested that the eliminate-and-split strategy is always the approach of scientists in such cases. We believe that this argument is based upon serious oversimplifications. To begin with, note that there is the assumption that scientists treat all discoveries about differences in realizers in the same way..