Sound
Not a lot of work has been done to develop a theory
of sounds. Of course, music theorists have studied sound’s relationship to aesthetic properties. But as far as I know, we don’t
yet have anything like axioms describing the nature of sounds and their
relationships to one another.
Sounds are like colors in
the following respects: (i) we can be directly aware of them; (ii) some sounds
are primary or fundamental building blocks of all other sounds; (iii) complex
sounds are built from various “saturations” of primary sounds; (iv) sounds are
often confused with the things that cause us to hear sounds, namely vibrations.
Although similar to colors, the nature of sounds might be less well understood
than the nature of colors.
Some might say that sounds, like colors, can only be
detected by way of a single sense perception. Shapes, by contrast, can be both
seen and felt. It seems to me, however, that there is only one kind of sense
perception, namely direct awareness. Our eyes help us become aware of colors,
though our eyes aren’t necessary for that—we can be aware of colors even while
our eyes are closed, such as when dreaming of a purple monster. Our eyes also
help us become aware of shapes. Our skin helps us to become aware of textures.
But I’m not sure we can feel shape. I suspect that instead we infer shape based
upon our tactile feelings. For example, we’ve learned to associate the feeling
of an open palm with a certain shape of the palm. Given this learned
association, when we press our palm along a surface, we infer that the surface
has an edge shaped the way our palm is shaped. So our awareness of the shape
isn’t given directly by touch. This
is just a suspicion of mine.
Sounds
vs. Vibrations
Sounds are often associated with the things that cause us to hear sounds—namely
vibrations of things (i.e., of substances),
where a vibration is a thing’s exemplifying of a dynamic
property that entails a change in a spatial relation (when I say ‘a thing’s
exemplifying P’ I mean a certain fact involving a thing
exemplifying P). It is common among scientists to identify sounds with vibrations. I believe this is a mistake. The
sounds we hear are not themselves changes in a spatial relation. This should be
no less obvious than the fact that sounds are logical relations, or that
spatial relations are themselves colors. When I focus on the shrill of her
voice, it is obvious to me that the shrill sound is not itself a change in any
spatial relation. See similar remarks regarding the relationship between colors and light reflective properties.
If
a Tree Falls…
If no one is around to hear the tree fall, does the
tree make a sound? I used to say “yes” on the grounds that sounds are
vibrations. The tree makes a vibration whether or not anyone is there to hear
it. But I believe I was confusing the cause of my hearing a sound with the
sound itself. A sound is not itself a vibration, though our hearing sounds is
often caused by vibrations of air molecules by our ear. (Note: I can hear
sounds even in my dreams when no vibrations are going on.) The question is
whether sounds get exemplified by things in the external world. To answer that,
it will help to know what sorts of things would exemplify sounds if sounds were
exemplified. My guess is that vibrations exemplify sounds and essentially so.
If that’s right, then insofar as trees cause vibrations when they fall, they do
make a sound. And that’s so even if no one is there to hear it. So my tentative
answer is still “yes”, but for a different reason.