In some conditions it looks as if we perceive light rays, e.g., in a dusty room. But what is actually perceived is a set of particles of water or of dust that intercept light. In order for a light ray to be visible, it would have to send information to our eye without the mediation of interposed matter. Coming back to sounds, the argument based on the constraint of fidelity to the content of auditory perception is thus, in a compact form: in order for sound waves to be audible, they would have t