Top-down vs. bottom-up — whole vs. parts

In the beginning, I was approaching The Nature of Order with this question in mind: “Is this theory a top-down or is it a bottom-up approach?”. Some aspects look clearly like a top-down approach. You keep looking at the whole and differentiate the parts more and more. But other aspects look more like bottom up: you take one step at a time, making decisions based on the current environment.

When Alexander later talks about the unfolding process and even more specifically in Book 3 about how to “reconcile two systems” of solids and voids or matter and space and achieve deep interlock between them, it became clear to me that he is talking about both at the same time.

Splitting solutions into either “top-down” or “bottom-up” is an analytical step itself deeply rooted in the mechanical worldview that everything is a machine-like mechanism that can be broken down into parts to be better understood, or organized into distinct categories which allow us to focus on parts in isolation.

Alexander’s critique applies to something rather specific such as building as much as it does to the meta-level of cognition and sense-making.