 Dretske’s view centers on the idea of representational systems as systems with the function of tracking features of the world (for similar views, see Millikan 1984, 2017; Neander 2017). Organisms, especially mobile ones, generally need to keep track of features of their environment to be evolutionarily successful. Consequently, they generally possess internal systems whose function it is to covary in certain ways with the environment. For example, certain marine bacteria contain internal magnets that align with the Earth’s magnetic field. In the northern hemisphere, these bacteria, guided by the magnets, propel themselves toward magnetic north. Since in the northern hemisphere magnetic north tends downward, they are thus carried toward deeper water and sediment, and away from toxic, oxygen-rich surface water. We might thus say that the magnetic system of these bacteria is a representational system that functions to indicate the direction of benign or oxygen-poor environments. In general, on Dretske’s view, an organism can be said to represent P just in case that organism contains a subsystem whose function it is to enter state A only if P holds, and that subsystem is in state A.