What is a Biological Function?
Patricia Diaz
International Conference on Formal Ontology in Information Systems (FOIS 2006)
Baltimore, Maryland (USA), November 9-11, 2006
Abstract
The concept of biological function is fundamental not only for the philosophy of biology, but also for formal representations in biomedicine. Biologists describe the role of traits in certain organisms using functional language, and the notions of health and disease have been defined by means of functional terms. The purpose of this paper is to clarify the concepts biological function, constituent function, and functioning that are more or less explicit in recent work on formal ontology and its applications in the biomedical domain. I will review several articles by Johansson, Smith, et al. Those articles represent a “neo-Aristotelian” approach: they assume a neo-Aristotelian ontology and theory of definition. It is common to distinguish two major approaches to defining biological functions with several variants. The first major approach began with Robert Cummins’ theory and is called the ‘Causal-role’ analysis of function (CR-function). For Cummins, the function of a part of a system is its causal contribution to some activity of the system. The second approach, endorsed by authors such as L. Wright and Ruth G. Millikan, has been called the ‘etiological’ or ‘evolutionary’ analysis of function (E-function). Wright proposed that the function of an organ or artifact A are those of its effects which explain A’s presence by means of a causal history. According to more refined versions of the second approach, the (proper) function of a trait is tied to its evolutionary significance, or it is determined by natural selection. The neo-Aristotelian-function (NA-function) can be fully assimilated neither to CR-function nor to E-function. In general, the NA-function analysis attempts to capture the non-explanatory elements of functional language and is non-reductive in the sense that it admits universals. The NA-analysis provides a metaphysical account of BF, covering aspects that are not emphasized by the other approaches.