The Importance of Closure in Software Architectures

The closure language was really, I remember Stuart Halloway in his program in closure book called it a minor miracle. But over the 10 years of kind of using it in a company, obviously the language itself doesn't tell you how to build a software architecture. And so I've been seeking how, what is it about closure that makes it work in the small and how, which principles and properties of closure could we bring and scale up and actually influence the architectures that we build?