juncture

The envelope is a line drawn in the sand.  Drawing that line is both a) declarative, whether it be a bold or unassuming statement, and b) a division.  The division does not need to happen all at once, it can be stretched or blurred, but it is held between a series of concepts.  

Inside/outside, private/public, context/building, systems/aesthetics/mechanics/structure/material.  Envelope is where everything collides: it is the point of juncture.  How we treat this juncture determines how our structures relate to the world and how the world relates to the functions within.  Is it literally transparent?  It is conceptual transparent? A translation of the interior? Permeable? Impermeable?  In a constant state of flux or in a state of permanence?  What are your priorities? What are you trying to communicate to the surrounding world?  Does it take on an air of composure or does it read like an open book?

Similar to architectural theory in a broad sense, all architects are making some sort of statement in the articulation of the envelope, whether they want to or not.