Word watch: “urban prairie.” Meaning when “vast tracts of formerly urbanized land return to nature.” Is this what should happen in Detroit? Some architects think so: “The American Institute of Architects produced a study that called for Detroit to shrink back to its urban core and a selection of urban villages, surrounded by greenbelts and banked land” (via NYTimes Ideas Blog).

This relates to something I’ve been pondering lately, which is admittedly not a new question, but basically the gist is: how will we know when we’ve overdeveloped the earth? Are we capable of that observation? Have too many of us built too much, used too much, interfered too much, taken too much? It seems like the tragedy of the commons might suggest one answer: we won’t know and won’t care. If we compare this predicament to what’s happened on Wall Street over the past year, there’s a similar human fault at work in both cases: greed. And to fix it, you’ve got to build an assumption of greed into the system. Quoting Warren Buffett: “The fact that people will be full of greed, fear, or folly is predictable. The sequence is not predictable.”

But, if I were to take a slightly more optimistic tack on this as we exit The Decade from Hell, I’d say building greed into the system is precisely where the opportunity lies for the next quantum leap in human understanding. And what’s great about that is that these sorts of leaps tend to happen precisely when we invent new ways to describe what we see. Paintings were flat, then algebra, then—boom!—Giotto. “Bad air” caused pandemics, then better maps, then—boom!—Dr. John Snow. We now have the most powerful tools for observing collective human action ever created. Let’s start using them to figure out how much is enough.