What is music?

That's the question crossing my mind again and again over the last few days.

What is it? And how about those who cannot hear? Saw 'Le Pays Des Sourd' (Land of the Deaf), a French documentary by Nicolas Philibert, adding to the curiosity. The first scene was a concert sort of thing being performed in sign language. If music can be felt, as many say it can be, then surely music goes beyond hearing. And to animals? What would it mean to them?

Hope to find out someday...