Where does sound come from? A thought experiment.
October 10, 2018
Stranded on a dessert island.
Imagine a person born blind, living alone, on a proverbial deserted island, out of touch with society, surviving through what she can grasp with her hands. Sight has never had an influence on her notion of reality.
From a hidden vantage point we notice that a bird is singing near where she is standing. We assume she hears it; but cannot see it. For her there is only a certain quality of sound, to which only we can give the name bird. For her, it never gets beyond being just a sound, although she can distinguish one sound from another on the basis of its quality.
Thus she is someone who 1) has never seen, 2) never seen a bird, and 3) wouldn’t be able to conceive that there is something called a bird. There are simply no past connections between the sense of sound and the sense of sight. There is nothing linking the sound of the bird with the sight of a bird.
If the question “why” arises in her mind, probably in the form of “why this sound and not another sound”, the question can only be posed by her within the domain of time and not space: “why do I hear that sound now and not at another time.”
At this moment, a miracle occurs.
Our subject can now see. One of the first things that happens is that she sees a bird, although it is not at that moment singing. Thus at this point there is no reason for her to form any sort of link between the sound of the bird and the image of the bird in front of her.
Some scientists now enter the scene.
They introduce themselves, and present her with a series of pictures. Included is a picture of the same species of bird that she has been hearing. She is asked to choose from among the pictures the one she thinks would be most closely associated with the sound she already knows.
This request perplexes her. She cannot even understand the general form of the question. At this stage of the story, sight is still new to her. She knows of no reason why a sight and a sound should be related to each other, even that they could be related to each other. While the sound, for the scientists is the “sound of a bird“, she has no need to make, or even conceive, such a statement.
She has no grounds for choosing one picture as against another. This makes it arbitrary which picture she chooses. If she is “artistic” by nature, perhaps she may form an aesthetic comparison: which sight feels like it goes with this sound.
Her judgment in this matter cannot yet be based on cause and effect. And even if she has a notion of cause and effect from her previous experiences in which there was no sight, sound as far as she can tell, needs no cause.
“Excuse me”, she asks, “are you saying that a sound requires a sight to cause it? That among all the random lines and shapes I see, which seem aimlessly distributed in space, there are certain lines and shapes that for a reason I cannot conceive ‘belong’ to each other, stand out from the other lines and shapes because of a mysterious relationship, which in turn you call the cause of the sound I have been hearing – not just now, but whenever I hear it.
When you speak of this mysterious connection between just certain lines and shapes, you use the strange word ‘object’, as if by saying that word it should be obvious to me why just those lines and shapes clump together with each other. And then, now that I supposedly believe in something called ‘the object’ whatever an object is, it is also the cause for the sound – something that never seemed necessary to me for the sound to occur. Why should there be such a complicated and seemingly arbitrary way of connecting things in my mind, based on an invisible (at least to me) concept called ‘object’, without which, you say, I would not hear my sounds. Furthermore that I have to choose among several of these objects, and pronounce the words ‘this object is the cause of what I hear?’ That sounds like an enchanter’s spell. My universe was full and complete without sound requiring a cause. Being sighted is sure a complex thing.”
At last she picks one of the pictures. “If I pick this picture today can I pick another picture tomorrow to be the cause of this particular sound in my head? I ask you this because for now, none of the pictures that you show me bear any inner resemblance to the sound that I know.” The psychologists say: “No, you must believe that a sound arises in your consciousness because of a certain event happening in space, which something has to do with a particular object that you see, and always that object and not another.”
She comes to her “senses”.
She is left alone for a few days to ponder this perplexing situation, a situation that until now, without sight, had no reason or necessity to exist.
During one of these days she just happens to hear the sound of the bird at the same time that she is looking at a bird. This may have happened on the preceding days, but this time she notices that the beak of the bird moves in tandem, in time, with the occurrence of the sound. She knows this much more because of time rather than space. The togetherness of the sight and the sound is based on a common moment in time.
This forms the basis of a series of ongoing experiences by which the sound of the bird is gradually linked in her mind to the image of the bird.
As with the pictures of shown by the psychologists to the girl, sights that are visible to a growing, young child at only at certain times, during for example a concert, are only gradually coordinated by that child with something seen in space in the concert hall. It turns out that the people who are holding musical instruments in their hands seem to make motions that are most consistently synchronous in time with the changes of the qualities of the sounds.
Here’s the first important point. Once such an association is made by the child, he or she forgets that there was a time when no such association had been made.
The second point is: was either the woman on the island, or the person in the concert hall, missing anything crucial when they was unable to relate the object ‘bird’ or the object ‘violin’ with a certain specific sound quality of sound? I say no. Nothing essential to our understanding and appreciation of sound is added to by the tacking onto the sound a relationship with sight. And in the concert hall, it adds nothing important to essential qualities of the music as sound alone.*
For those of us who do not need such distractions as sight offers, and can remain glued to the sounds of the piece, we enter an ideal realm of pure relationships between pure sounds, closed off from everything else, and not lacking a thing.
* It is for some but not all of the concert goers, that visual impressions can serve as a distraction or refuge from just having to listen to sound from one moment to the next. For them there are the distractions of the appearance of the concert hall. For them, too, there is the all important information in the program notes, which they are relived to believe captures something essential that they miss in the progression of the sounds alone. But thanks to the program notes, they are able to go up to someone at intermission and say, wisely: “wasn’t it wonderful how the composer used the brass section in the second movement of the symphony to create a delicate halo of sound around the rest of the orchestra!”.