<p> <?tk 4?>Biological function ascriptions are often thought to present distinctive philosophical puzzles: they screen off a part’s purpose from merely accidental effects of its presence and they provide a certain kind of explanation. I propose a naive, ahistorical account of functions to resolve these puzzles: the function of a part is what it does. We can help ourselves to this view if we understand function statements as generics. It is, I argue, then their generic form that is responsible for screening off the purpose of a given part from accidental effects. In other words, I take it that one of the problems that function ascriptions are thought to raise is in fact a problem arising from the thorny semantics of the wider class of sentences to which they belong. I then propose a deflationary conception of their explanatory power by distinguishing two often conflated questions: how did a given part come to have the function it has, and what does the function explain. In short, functions have historical explanations but they do not provide historical explanations.<?tk 0?></p>