If a Tree Falls ....

There is an old philosophical question: If a tree falls in the forest and no one is there to hear it, does it make a noise?

The subjective idealists said no. A noise is a perception, an experience in someone's mind. If there is no experience, there is no noise.

Aristotle said yes. A noise is a "potency," the physical event that has the power to create that perception. If the physical event occurs, then there is a noise. Today, of course, we know that the physical event is a vibration of the air (or of water), which our eardrums detect and our brains convert to a subjective perception of noise.

This question has always been presented as an insoluble puzzle, but the answer should be obvious: It depends on your definition of noise.

If we define noise as a subjective perception, then the falling tree that no one hears does not make a noise. If we define noise as vibrations in the air that have the power to cause this subjective perception, then the falling tree that no one hears does make noise.