Building on the theme of time again he quotes Frank Duffy (ex president of the Royal Institute of British Architects) "Our basic argument is that there isn't such a thing as a building. A building properly conceived is several layers of longevity of built components".
Some layers live longer than other layers.
Some layers are more stable than other layers.
Layers change at differing rates.
The rates of change over time define the layers as clearly as the individual physical changes.
Brand extends Duffy's four S's shearing classification to six S's: Site, Structure, Skin, Services, Space plan, Stuff.
Quoting Duffy again "The unit of analysis for us isn't the building, it's the use of the building through time. Time is the essence of the real design problem."
Many buildings are demolished early if their outdated systems are too deeply embedded to replace easily.
Hummingbirds and flowers are quick, redwood trees slow, and whole redwood forests even slower. Most interaction is within the same pace level.
The dynamics of the system will be dominated by the slow components, with the rapid components simply following along. Slow constrains quick; slow controls quick.
Echoing the quote from Churchill, that the building learns from it occupants and they learn from it, he provides a fascinating insight - "In classical Greece and Rome domus meant house in an expanded sense: People and their dwellings were indistinguishable: domus (as in Romanes eunt domus - Life of Brian) referred not only to the walls but also to the people within them."