He pointed to two key principles that these systems need to have to learn solutions, based on observations from biology:
- Meaningful variation - Variations can't just be random, the mutations and selections have to produce meaningful effects in the domain.
- Heritability - children need the ability to inherit desirable features from the parent without being clones.
I think there's still interesting work combining GP with IR. For example, one problem is that collections and users evolve over time, but most ranking functions are static.