Bateson does in fact define his use of logical levels (and they are logical levels of learning) I am not sure what you mean by Bateson having defined them, "in the way mentioned in that article" as I don't know the article to which you refer. However, you can find Bateson's discussion in one of: "Mind & Nature" or "Steps to an Ecology of Mind" I don't recall which, but try "mind and nature" first. Sorry I can't be more specific, but I don't have access to the bookcase at the moment... These are both a good read on some of the 'ground' out of which NLP grew. This relationship will be fairly translucent to those who know the new coding. bye for now, Todd