 Neander’s starting point is the notion of a response function (Neander 2013; 2017, ch. 6). She claims that sensory-perceptual systems have such response functions, where to ‘respond’ to something is to be caused by it to do something else. For example, a visual system might be caused by a red instantiation to change into a RED state, and it might have been selected (in part) for being disposed to do so. This means, according to Neander, that the system has the function to respond to red instances by changing into a RED state.