 In  case (b),  (sound) waves are different from processes and are peculiar just because waves move, as individual substances do. But again, if sound waves move, the corresponding sounds are not generally heard as moving. (Contrast this case with seeing a sea wave’s phase at a particular place.) Sound waves propagate in all or most directions from a sounding object, but the corresponding sounds are not actually heard as propagating in any direction: the only moving sounds are the sounds emitted by a moving source. It follows that if sounds were sound waves in this sense, we would not be hearing them as they are.