The so-called 'pre-conscious' (mind) is the 'BRIDGE of REASON' located between the 'un-conscious mind'; and the 'conscious mind.' It is an inter-face; a variable inter-face. And, as we already know, every 'interface' without exception has two sides. In this case an 'inner-most' and an 'outer-most.'
The 'point of meeting' is also the 'balance point' between the two sides. In the inter-human world, this is the ultimate inter-face; (or 'divide') - the ultimate 'boundary' between 'self' and 'other.'
When I speak of 'self' and 'other' in this 'inter-human' context, I am not only referring to 'inter-personal' dynamics, but also, the whole world, or 'field' of 'THE OTHER.' That is to say, whatever is perceived to be 'OTHER' than SELF. This could extend from the everyday distinction one makes between ones own body (skin of fingers and hand, e.g.); and the sharp edge of a knife that one is using to cut up vegetables or meat, etc. - to the distinction that one makes between what are perceived to be 'healthy' body cells; and what are perceived to be 'unhealthy' (diseased) cancerous cells - which are ordinarily perceived to be 'invading' ones very own body-self! Indeed, this is a pretty wide field! However, the really important (crucial) point is - where, how and why we make these distinctions.
In fact, it is such a broad field, that it is indeed necessary to take it a little bit at a time, as it were. Or, to put it another way, it is indeed necessary to view the TOTAL SITUATION, from a number of angles; and propose a number of qualitatively different LEVELS, of what is ultimately a global UNITY of some kind.
It would seem that I have diverged somewhat from my original intention of depicting as accurately as possible in essentially 'structural' terms, a specific 'location' or 'region' of the 'total mind.'