Functions, Malfunctioning, and Negative Causation

Abstract

Functional explanations apply not only in cases of normal functioning, but also in the case of malfunctioning. According to a straightforward analysis, a bearer of the function to F is malfunctioning if and only if it does not F although it should do so. This makes malfunctions and malfunctionings analogous to negative causation and thus peculiarly problematic, because they seem to involve absent dispositions and absent processes. This analysis seems also to require that the function to F cannot be identical with the disposition to F. Then we seem to be trapped in a dilemma: Either the realm of functions is separated from the realm of dispositions; then it seems that functions cannot be causally efficacious. Alternatively, functions are considered to be identical with dispositions; but then malfunctioning seems to be conceptually impossible. The paper defends and further develops the thesis of Röhl and Jansen (J Biomed Semant 5:27, 2014) that functions are not a special type of dispositions. For this purpose, it first reviews different varieties of malfunction and malfunctioning and suggests definitions of both malfunction and malfunctioning. It reviews how causal, etiological and intentional theories of functions can deal with these problems. In particular, the paper discusses the special-disposition account of the Basic Formal Ontology (BFO). Spear, Ceusters and Smith (Applied Ontology 11(2):103--128, 2016) have defended the special-disposition account of the Basic Formal Ontology (BFO) by suggesting various strategies how a special-disposition account can deal with malfunctions. On the one side, the paper evaluates these strategies and indicates several problems arising from them. On the other hand, it describes how to account for the non-optionality and the causal efficacy of functions, if functions are not dispositions. While function types are not identical to disposition types, there are important interrelations between functions and dispositions, namely (1) heuristically, (2) from a design perspective for artefact functions, and (3) from an evolutionary perspective for types of biological functions.