 One aspect of Millikan’s theory that has received much attention in the literature is the fact that it entails, at least in certain cases, content ascriptions of a distinctive kind. This is well illustrated by the frog example. Let us suppose, for the sake of simplicity, that the frog’s sensory-perceptual representation belongs to a set of representations that only vary with respect to the time and place of their occurrence, and let us call this the system of ‘R-representations’. To find out what the content of the R-representations is, according to Millikan, we must first identify the proper function(s) of the frog’s prey-catching system (the consumer of the R-representations). Plausibly, the prey-catching system has the function of providing the frog with food, since there can be no doubt that the procurement of food was the fitness-enhancing effect that ancestral prey-catching systems (in ancestral frogs) had on former occasions that led to the proliferation and preservation of such systems. In a second step, we have to figure out what the correspondence relation is that has to obtain between the R-representations and the world if the prey-catching system is to perform its food-providing function in the Normal way (i.e. in the way that the ancestral systems did it). The answer is, quite obviously, that the correspondence relation has to obtain between R-representations and the presence of frog food. Hence, an R-representation occurring in location l at time t has the content there is frog food present in l at t, rather than (say) there is a fly in l at t or there is a small, dark, moving object in l at t (cf. Millikan 1991, 163). (This point will be discussed further in  section 4.1.)