> I still don’t appear to be wrong. Procedures are not functions! I can understand the confusion since both Java and OCaml will let you define both. Procedures

> I still don’t appear to be wrong. Procedures are not functions! I can understand the confusion since both Java and OCaml will let you define both. Procedures have side-effects, e.g. mutating global state, (pure) functions don't. Functional programmers work with predominantly immutable values and this requires a very different style of programming - one that many people struggle with if they have not had much exposure to it. Functional programming languages also have syntax and abstractions (often taken from maths) that are not used in object oriented programming. Why program with functions and immutable data? It enables better composition.