Karen Neander

(1954 - 2020)

On dit souvent que, tandis que la biologie de l'évolution utilise un concept étiologique de fonction (la fonction d'un trait biologique n'est autre que son effet sélectionné), la physiologie prend appui sur un autre concept de fonction, celui de rôle causal. Cependant, un examen plus attentif montre que le concept non normatif de rôle causal n'est pas ce dont la physiologie générale ou la neurophysiologie ont besoin. Ces disciplines font un large usage de notions comme celles de bon fonctionnement, de fonctionnement normal, de fonctionnement perturbé ou de trouble fonctionnel. Il semble ainsi qu'un concept normatif comme le concept étiologique n'est pas seulement utile dans le contexte d'explications téléologiques ou évolutionnistes, mais aussi dans celui d'explications mécanistes ou opérationnelles telles qu'elles sont couramment proposées par la physiologie. La différence entre types d'explication n'est pas une différence entre deux concepts de fonction. En particulier, l'analyse physiologique serait une tâche impossible si elle devait prendre en compte toutes les relations causales à l'intérieur de l'organisation fonctionnelle de chaque système biologique. Pour résoudre ce problème, la physiologie doit être une analyse du fonctionnement normal du système, quelle que soit la part d'idéalisation nécessaire. La notion de bon fonctionnement, conçu comme le produit de l'histoire évolutive, nous aide en particulier à comprendre pourquoi les systèmes qui fonctionnent bien se ressemblent, et pourquoi les systèmes qui dysfonctionnent peuvent le faire de tant de façons différentes. It is often claimed that although evolutionary biology uses an etiological concept of function (according to etiological theory, the function of a biological feature is its selected effect), physiology relies on a different concept of function, the causal role concept. However, upon closer scrutiny, it appears that the non-normative causal role concept is not what is needed by physiology or neurophysiology. These disciplines make a wide use of normative notions like proper functioning, normal functioning, impaired functioning, or functional disorders. In this case, it seems that a normative concept like the etiological concept is not only useful in the context of teleological or evolutionary explanations, but also in the context of mechanical or operational explanations as they are routinely offered by physiology. The difference between types of explanations is not a difference between two kinds of concepts of function. In particular, physiological analysis would be an impossible task if it had to take into account all causal links within the functional organization of each biological system. To solve this problem, physiology has to be the analysis of the proper or normal functioning of the system, even if normal functioning is usually obtained through a process of idealization. The notion of proper functioning, conceived as the product of evolutionary history, helps us understand, among other things, why properly functioning systems tend to be similar, and why malfunctioning systems may differ in so many different ways

This article argues that at least very many judgments of homology rest on prior attributions of selected‐effect (SE) function, and that many of the “parts” of biological systems that are rightly classified as homologous are constituted by (are so classified in virtue of) their consequence etiologies. We claim that SE functions are often used in the prior identification of the parts deemed to be homologous and are often used to differentiate more restricted homologous kinds within less restricted ones. In doing so, we discuss recent criticism of this view that has been offered (especially that offered by Paul Griffiths). *Received July 2007; revised November 2008. †To contact the authors, please write to: Department of Philosophy, 201 West Duke Building, Box 90743, Durham, NC 27708; e‐mail: [email protected] or [email protected].

In this paper I defend an etiological theory of biological functions (according to which the proper function of a trait is the effect for which it was selected by natural selection) against three objections which have been influential. I argue, contrary to Millikan, that it is wrong to base our defense of the theory on a rejection of conceptual analysis, for conceptual analysis does have an important role in philosophy of science. I also argue that biology requires a normative notion of a "proper function", and that a normative notion is not ahistorical