Looking for: complex systems that defy model reduction.
The behavior of a complex system is hard to predict from its parts alone because it follows from how the parts interact.
Model reduction is a way to capture the behavior of a complex system more simply (eg to capture the magnetism of 1g of Fe2O3, you don't have to model all 1022 molecules and their interactions). My sense is that model reduction works best when you have many repeated copies.
I'm looking for some good (ideally concrete) examples of complex systems that defy model reduction. I anticipate that they will be made of heterogeneous parts.
