 The deviant paths of sound waves (in echoes) is responsible for the perceptual difficulty in locating sounds, much as the deviant path of light rays (in mirrors) is responsible for the analogous difficulty for visible objects (Casati &amp; Dokic 1994; see also O’Callaghan 2007 for a lengthy discussion of echoes, and Fowler 2013 for arguments against O’Callaghan’s view). But it is not the case that sound waves are sounds just because of their responsibility. From the fact that a subject hears something as imperfectly located, it does not follow that she hears something which is imperfectly located.