 Two lines of response are open. The first appeals to the thriving empirical research program in “spatial hearing” (see, e.g., Blauert 1997). Scientists aim to discover the cues and perceptual mechanisms that ground spatial audition, such as interaural time and level differences, secondary and reverberant signals, and head-related transfer functions. Audition clearly cannot match vision’s singular acuity—vision’s resolution limit is nearly two orders of magnitude better than audition’s (Blauert 1997, 38–9). Nevertheless, this research strongly supports the claim that human subjects auditorily perceive such spatial characteristics as direction and distance.