I met Bill in Linz, Austria at a IFSR 
(International Federation for System Research) dialogue. For several months afterwards we tried to match up his pattern work in engineering and my work in neighborhoods. Some progress, by not a workable product, yet. Both of us are inspired by Christopher Alexander's use of patterns and pattern languages.
One of may interesting things that Bill says is that Hamilton's Laws provide the fundamental basis for system science and that the search for the unifying concept for system science is taken care of.