You're nitpicking. GP said: > If objects are mutable then the order of execution matters, and you have to trust the programmer to get the data flow and control

You're nitpicking. GP said: > If objects are mutable then the order of execution matters, and you have to trust the programmer to get the data flow and control flow to agree My point is that, even in FP, as soon as you hit sequential operations (in your example, side effects), you're still bound by the execution order and the programmer getting it right (and how that is completely orthogonal to OOP or FP). Order-dependent sequential operations are the programmer's responsibility regardless of paradigm. I don't think OOP is inherently sequential. Your post made me realize GP is conflating OOP and imperative programming and his post makes sense if :%s/oop/imperative programming/.