 Technical artifacts, then, are made to serve some purpose, generally to be used for something or to act as a component in a larger artifact, which in its turn is either something to be used or again a component. Whether end product or component, an artifact is ‘for something’, and what it is for is called the artifact’s function. Several researchers have emphasized that an adequate description of artifacts must refer both to their status as tangible physical objects and to the intentions of the people engaged with them. Kroes and Meijers (2006) have dubbed this view “the dual nature of technical artifacts”; its most mature formulation is Kroes 2012. They suggest that the two aspects are ‘tied up’, so to speak, in the notion of artifact function. This gives rise to several problems. One, which will be passed over quickly because little philosophical work seems to have been done concerning it, is that structure and function mutually constrain each other, but the constraining is only partial. It is unclear whether a general account of this relation is possible and what problems need to be solved to arrive there. There may be interesting connections with the issue of multiple realizability in the philosophy of mind and with accounts of reduction in science; an example where this is explored is Mahner and Bunge 2001.