The sickle cell allele is a pathology for the hematologist and a protective advantage for the malaria epidemiologist. The peacock's train is a sexual ornament for the evolutionary biologist and a deterrent display for the ecologist. In each case, the parties agree on what the biological process does. They disagree on its functional status because they assess it against different evaluative contexts. This paper argues that persistent debates about biological function share this structure: the parties attribute function to the same process but leave implicit the evaluative context from which they assess it. Making that context explicit yields a diagnostic distinction. Some disagreements are empirical (the parties share a context and disagree about the facts); others are evaluative (the parties assess from different contexts, and no empirical finding can settle the difference). Three cases (sickle cell hemoglobin, the peacock's train, and bacterial antibiotic resistance) illustrate the argument. The paper does not propose a new theory of function. It identifies an operation (declaring the evaluative context) that clarifies what kind of disagreement is at stake. Function is not in the hemoglobin or the tail or the gene, but in the relation that binds them to the evaluative context of their assessor.
Didier Barret (Mon,) studied this question.