Literally the second section: > Here is the central claim: the unit of correctness in production is not the program. It is the set of deployments. The thesis

Literally the second section: > Here is the central claim: the unit of correctness in production is not the program. It is the set of deployments. The thesis essentially boils down to: functional programing paradigm, type systems, strong interfaces, etc, are all fantastic tools for ensuring the correctness of a program, but the system is not a program, and so these tools are necessary but not sufficient to ensure the correctness of a distributed application.