I think the point here is that we don't need to define a fitness function for "good music", but a fitness function for e.g. "reconstruction error" for auto-enco

I think the point here is that we don't need to define a fitness function for "good music", but a fitness function for e.g. "reconstruction error" for auto-encoders. While the latter is still challenging, it seems slightly easier, although I'm not sure that it's significantly easier than general manifold learning...