© 1988 by The Society for Integrative and Comparative Biology
The Nature of Explanations in Morphology1
Department of Biological Sciences, Columbia University New York, New York 10027
SYNOPSIS. Explanations in morphology can be classified into functional and evolutionary explanations which do not coincide with the limits of functional morphology and of evolutionary biology as usually recognized. Functional explanations are nomological-deductive in form and deal with many aspects of morphology such as how structures operate, correlations between form and function, and the adaptiveness of features. Evolutionary explanations cover the historical origin of features and use historical-narrative analysis as the basic method. The results of these two types of explanations are quite complementary. It is clear that functional explanations can never be complete no matter how detailed they are, and that evolutionary explanations are absolutely dependent on prior functional explanations. Functional explanations, however, can be made independently of evolutionary explanations. A case study is presented dealing with the relationships between several categories of properties in the form-function complex, namely the possibility of predicting or explaining one property of a feature given a second property under a strict functional explanation. It was shown that it is possible to predict properties of function given the form of a feature, even if the feature is a complex one. However, it is not possible to predict uniquely the properties of form of a feature given its function in a functional explanation. Nevertheless, both types of explanations are most valuable in theoretical and empirical anatomical studies, and should be used to their fullest. Predictions of possible morphological form from known properties of function is one of the most powerful research strategies in morphology in discovering new anatomical features as well as providing an essential foundation for any evolutionary explanation in morphology.