Deterministic Core, Non-Deterministic Shell

The author discusses the concept of a deterministic core and non-deterministic shell in the context of software design, citing the example of a chess engine that uses a deterministic core to generate moves and a non-deterministic shell to make decisions based on the game state. The author argues that this architecture can provide a good balance between predictability and adaptability. The discussion also touches on the concept of a 'mixed' system, where the core and shell are intertwined, and the challenges of creating a system that combines determinism and non-determinism.