The concept of biological function has been a persistent source of debate in the philosophy of biology. This is driven in part by attempts to develop a unified account of function that can be applied across diverse biological disciplines. I suggest that such attempts may motivate the extension of particular accounts of function into unsuitable domains. At the same time, adherence to a single account risks paying inadequate attention to how the concept is currently being deployed within specific fields. I use the function debate within the philosophy of psychiatry to explore how prior explanatory commitments can motivate preferences for particular theories, resulting in poor explanatory fit. Instead, I argue that function can be understood as scientifically polysemous, whereby different subdisciplines may use the concept to refer to different properties or processes that are salient within that domain. I suggest that such variation can be legitimate when anchored to the epistemic and pragmatic goals of the field in question. Finally, I explore how the framework provided by a patchwork concept might help constrain the legitimate use of the function concept across different scientific contexts (Haueis, 2024).