2a. The natural and proper action of anything; special activity; office, duty, calling, operation, or the like. 2b. The natural or characteristic action of any power or faculty. 10. Physiol. The normal and special action of any organ or part of a living animal or plant. According to The American Heritage Dictionary, Windows version, a function is 1. The action for which one is particularly fitted or employed. 2a. Assigned duty or activity. 2b. A specific occupation or role... 4. Something closely related to another thing and dependent on it for its existence, value, or significance". I don't know of any discussion of function in philosophy or biology that doesn't fit under one or more of these clauses. Nor is the use of the term "function " in contemporary biology tightly defined or univocal, either within or across subdisciplines. Argument over THE correct analysis of THE concept of function either in ordinary life or in biology is, I believe, quite pointless. On the other hand, questions about the applicability, clarity, determinateness, and usefulness to biology of various of Philosophy.