  Now, selection processes can be intentional or non-intentional. Artifacts (including words and other symbols of natural languages) derive their functions from some intentional process. While psychological mechanisms (e.g., belief-forming mechanisms) derive their proper functions from a non-intentional selection process, particular belief states have derived proper functions. The paradigmatic non-intentional process is the process of natural selection by which Charles Darwin explained the phylogenetic evolution of biological species: natural selection sorts organisms that survive. But no intentional agent is responsible for the sorting. Millikan (1984, 2004, 2005) has also extended her teleosemantic approach to the contents of intentional conventional signs (i.e. linguistic symbols). If this sort of teleosemantic proposal could be fully worked out, then it would kill two birds with one stone. On the one hand, it would point a way in which the intentionality of minds derives from the intentionality of biological things (see Rowlands 1999 for discussion). On the other hand, it would show that some of the normativity of mental states is already exhibited by biological functions (see Neander, 1995). Both questions are currently topics of much discussion in the philosophy of mind. Many philosophers such as Davidson (1980), Kripke (1982), McDowell (1994) and Putnam (1988, 1994), for example, have either expressed serious reservations about the program or provided reasons for scepticism. For further discussion, see the essays in MacDonald and Papineau (eds.) 2006, and also the entries on  teleological theories of mental content and  teleological notions in biology.  Subsequently Burge (2010)  criticized attempts to naturalize intentionality by appeal to the notion of biological function on the grounds that it is, according to him, a deep mistake to identify representational success (truth or accuracy) with fulfillment of biological function and representational failure (falsity or inaccuracy) with failure of biological function. Unlike representational (or semantic) success or failure, fulfillment or failure of a biological function is, according to Burge, practical success or failure. 