[adamnemecek]

> 1. Why do we like pieces when played forward but not backward or inverted?

Would you like a movie played backward?

> 2. Why do certain sounds evoke certain emotions?

Large part of this boils down to if the waves representing the sounds meet at zeroes or not.

> 3. How could you write a program to pick out music that people find especially good (versus music that has surface similarities)?

I think that this is currently impossible. The music composition search space is actually extremely large, larger than say the search space of Go. You can restrict the search space quite a bit but it's still large.

> In other words, why does a particular sequence of sounds A, B, C lead to a mental state M that has particular internal qualities?

Think of it as design. It's the same sort of problem.