In reality, everything is an instrument; everything either makes a sound or can be interacted with so as to create a sound. Our ancestors 20,000 years ago probably had a much richer sense of this than we do, for the distinction between instrument and not-instrument is not inherent in reality itself; it is a cultural abstraction that we have imposed on reality. And this is a loss because to make sound with something is to get to know it and understand it better and perhaps even feel a sense of oneness with it. I suspect that they enjoyed reawakening us to this fact that everything in the world is teeming with vibrations that are waiting to be explored.