 Function is a salient feature of artifacts. Clearly there would be no good reason to keep so many of them around unless they did something for us. Function is also a salient feature of biological traits. Accounts of biological function, which now comprise a large literature, have inspired many accounts of artifact function. But unlike organisms, artifacts are made to serve human purposes, so human intentional states must be considered. Accounts of artifact function can be usefully categorized in terms of the role they give to intentions in the establishment of functions (Preston 2009; Houkes &amp; Vermaas 2010). At one end of the spectrum are accounts that revolve around human intentions, while at the other end are accounts that focus on non-intentional factors; in between are a variety of accounts that mix intentional and non-intentional factors in various proportions.