In any case, the question you point to highlights the problem with a developmental line that postulates the almost sudden emergence of a new and radically different psychological agency/function. I think that’s why Klein departed from Freud on the emergence of an ego and a super-ego, for instance.

What I’m trying to do here is to take from Winnicott the idea of the found object and make something of it that doesn’t have to rely on a developmental topology/chronology. My hunch is that the other-than-me is not a quality of the object but of the subject’s relationship to that object and that the relationship itself is not necessarily bound by location (inside/outside) or sequence (pre/post).

We’ll see if this works.

On a related note, I just saw a reference this article demonstrating that magpies recognize their own reflections in a mirror.