A recent article in the New York Times, in the science section no less, addresses the connection between science and music: how scientists are "trying to understand and quantify what makes music expressive--what specific aspects make one version of, say, a Beethoven sonata convey more emotion than another." The article is entitled "To Tug At the Heart, Music First Must Tickle the Neurons.".
The focus of this article is on how particular performances of a musical piece can affect the emotional appeal of it. It demonstrates, for example, that a piece of music is often enhanced by the particular interpretation given to it by the artist.
Some of the emotional impact of a piece, however, is based on the way it is composed, including the duration of notes and rhythms, and "the element of surprise." Daniel Levitin, a professor at McGill University in Montreal, suggests that "the more surprising moments in a piece, the more emotion listeners perceive--if those moments seem logical in context."
The cellist Yo-Yo Ma elaborates on this theme of surprise. Let's say he is playing a 12-minute sonata featuring a four-note melody that recurs several times. On the final repetition, the melody expands, to six notes."
If I set it up right," he says, "that is when the sun comes out. It's like you've been under a cloud and then you are looking once again at the vista and then the light is shining on the whole valley."
He cites Schubert's E-Flat trio as an example, when it goes from "a march theme that's in minor and it breaks our into major, and it's one of those goose-bump moments."
For me, the Tchaikovsky Violin Concerto has one of those goose-bump moments, when the melody sung by the violin is suddenly interrupted by another, different, melody, on the flute.
So maybe this is the essence of beauty: something, whether visual, aural, or experiential, that gives you goosebumps. Something that touches you emotionally.
(p.s. Joe, the doubter of aural beauty, admits that Dvorak's New World Symphony gives him goosebumps!)