We’re not fooling around today. It’s time to get to the bottom of this. Music is universal to all human cultures. And more than that, there is a broad range of agreement across cultures about what music should be made of. Some intervals of tone are considered pleasant across all cultures and some scales, ways of dividing up big intervals of tones into smaller intervals, developed independently of each other.
This is a tip off that music is made possible by the shared human physiology of pitch perception. That’s true, but it goes deeper than that, much deeper: All the way down to fundamental physics.
As usual, Vi Hart is smarter than I am and she explains this much better than I could:
There’s a lot going on here, pause and contemplate if you need to. The upshot is that the ear is evolved to hear distinct pitches and their overtones because they are a basic property of many types of physical systems that cause vibrations in the air.
But are overtones really that common in nature? Many natural sounds are “white noise”, sound smudged out across many frequencies. Rustling leaves and running water are good examples. So why have ears that can hear the overtone series and other ratios so distinctly. I can only speculate here, but perhaps hearing ratios helps an animal distinguish between running water and rustling leaves. Or maybe it’s because animals on land started intentionally making noises at each other. Most sound producing organs are simple physical systems that can clearly produce these simple ratios of frequencies.
It turns out mystics were right. The ratios of music and its periodic behavior really are the stuff of the universe. Electromagnetism can be modeled as a type of wave motion, so can gravity. The possible positions of an electron are a series of standing waves. It’s all rather eerie.
Of course, it’s possible that the facts about how our ears work caused humans to impose this type of order on the cosmos. Perhaps aquatic aliens for whom there is little distinction between sound and touch might come up with a very different way to represent to themselves the phenomena of the cosmos.
Bonus Research Links:
Some readers may know that the harmonic tuning system in Vi’s video starts to fall apart when you want to build a piano. Minute Physics explains why and what was done about it. That trick about playing Taps on bass or guitar in the link really works. Took me just a few minutes to figure it out.
Minute Physics brought up some serious math. Vi Hart makes that stuff seem so simple. I think her brain just works differently from most of ours. I think she really can smell the insides of numbers exactly as she says she can.
Bobby McFerrin schools neuroscientists on the power of the pentatonic scale.