According to Blajeny, what is Metron Ariston in the novel, A Wind in the Door?

According to Blajeny, Metron Ariston is more of an idea or a postulatum than an actual place, although it looks like a physical place to the children while they are there. Within Metron Ariston, size is relative. The children are able to see the microscopic farandola, Sporos, as if he were actually their own size. Interestingly, the name the author has chosen for this place/postulatum is an actual phrase meaning "all things in moderation" or "the Golden Mean."