The problem I have with this is that I haven't seen a precise definition of the difference between behavior and implementation. Another word that people use for

The problem I have with this is that I haven't seen a precise definition of the difference between behavior and implementation. Another word that people use for behavior is 'specification'. However, a spec that has been sufficiently formalized (so that it can be executed) is an implementation. Maybe an implementation with certain (desirable or undesirable) characteristics, but still an implementation. Of course there are informal, incomplete specifications that can't be executed. Those also have value of course, but I'd argue that writing those isn't programming.